Pumped Hydro Energy Storage for Hybrid Systems 0128188537, 9780128188538

Citation preview

Pumped Hydro Energy Storage for Hybrid Systems

This page intentionally left blank

Pumped Hydro Energy Storage for Hybrid Systems Edited by

AMOS T. KABO-BAH Civil and Environmental Engineering Department, University of Energy and Natural Resources (UENR), School of Engineering, Sunyani, Ghana

FELIX A. DIAWUO School of Energy, University of Energy and Natural Resources (UENR), Sunyani, Ghana; Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana

ERIC O. ANTWI School of Engineering, University of Energy and Natural Resources (UENR), Sunyani, Ghana; Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana

Academic Press is an imprint of Elsevier 125 London Wall, London EC2Y 5AS, United Kingdom 525 B Street, Suite 1650, San Diego, CA 92101, United States 50 Hampshire Street, 5th Floor, Cambridge, MA 02139, United States The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, United Kingdom Copyright © 2023 Elsevier Inc. All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Details on how to seek permission, further information about the Publisher’s permissions policies and our arrangements with organizations such as the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website: www.elsevier.com/permissions. This book and the individual contributions contained in it are protected under copyright by the Publisher (other than as may be noted herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary. Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using any information, methods, compounds, or experiments described herein. In using such information or methods they should be mindful of their own safety and the safety of others, including parties for whom they have a professional responsibility. To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any liability for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the material herein. ISBN: 978-0-12-818853-8 For Information on all Academic Press publications visit our website at https://www.elsevier.com/books-and-journals

Publisher: Charlotte Cockle Acquisitions Editor: Peter Adamson Editorial Project Manager: Howi M. De Ramos Production Project Manager: Prasanna Kalyanaraman Cover Designer: Greg Harris Typeset by MPS Limited, Chennai, India

Contents List of contributors Foreword Preface Acknowledgments

1. Energy storage technologies

xi xiii xvii xxi

1

Ebenezer Nyarko Kumi 1.1 Introduction 1.2 Energy storage classifications 1.2.1 Mechanical energy storage systems 1.2.2 Thermal storage systems 1.2.3 Chemical energy storage 1.2.4 Electrochemical energy storage 1.2.5 Electrical energy storage 1.3 Emerging energy storage technologies 1.3.1 Tesla powerwall and powerpack 1.3.2 Vanadium redox-flow battery 1.3.3 Solid-state batteries 1.4 Case study applications of energy storage solutions 1.4.1 Off-grid school lighting in Angola 1.4.2 Off-grid frequency response in Alaska 1.4.3 Time shift and ancillary services case study in China 1.5 Barriers and challenges in energy storage technologies 1.5.1 Cost 1.5.2 Market risk and business model 1.5.3 Modeling challenges 1.5.4 Technology risk 1.5.5 Regulatory barriers 1.6 Conclusions References

2. Need for pumped hydro energy storage systems

1 2 4 8 9 11 13 14 15 15 16 16 16 17 17 18 18 18 19 19 19 20 20

23

Felix A. Diawuo and Roland Teye Amanor 2.1 Introduction 2.2 Benefits of pumped hydro energy storage

23 27

v

vi

Contents

2.2.1 Load balancing and peak shaving 2.2.2 Grid stabilization- voltage and frequency regulation 2.2.3 Fast and flexible ramping 2.2.4 Black start 2.3 Hybrid pumped hydro energy storage designs and applications 2.3.1 Off-grid/standalone applications 2.3.2 Grid application 2.4 Climate change impact on pumped hydro energy storage and its infrastructure 2.4.1 Climate adaptation and mitigation options 2.5 Conclusions References

3. Characteristic features of pumped hydro energy storage systems

27 29 31 31 32 32 35 37 38 38 39

43

Felix A. Diawuo, Eric O. Antwi and Roland Teye Amanor 3.1 Introduction 3.2 Description of pumped hydro energy storage systems 3.2.1 Classification of pumped hydro energy storage 3.3 Pumped hydro energy storage characteristics and configuration schemes 3.3.1 Pumped hydro energy storage designs and configuration schemes 3.3.2 Advantages and disadvantages of pumped hydro energy storage 3.4 Conclusions References Further reading

4. Impact of market infrastructure on pumped hydro energy storage systems

43 44 45 50 53 55 57 57 58

61

N.S.A. Derkyi, J.Y. Kusi, M.A.A. Derkyi and Martin Kyereh Domfeh 4.1 Introduction 4.2 Current market overview and future trends 4.3 Existing market infrastructure and their impact on pumped hydro energy storage 4.3.1 Electricity market for pumped hydro energy storage 4.3.2 Types of market infrastructure for pumped hydro energy storage 4.3.3 Market structure of pumped hydro energy storage at the time of commissioning 4.3.4 Impact of market Infrastructure on pumped hydro energy storage 4.4 Conclusion References

61 64 66 66 67 68 68 70 71

Contents

5. Case studies on hybrid pumped hydro energy storage systems

vii

73

Mathew Anabadongo Atinsia, Williams Amankwah, Emmanuel Yeboah Asuamah and Felix A. Diawuo 5.1 Introduction 5.2 Configurations of hybrid systems 5.2.1 Hybrid pumped hydro energy storage-wind 5.2.2 Hybrid pumped hydro energy storage-solar photovoltaic 5.2.3 Pumped hydro energy storage-solar-wind hybrid systems 5.3 Existing cases of pumped hydro energy storage hybrid systems 5.3.1 Pumped hydro energy storage-wind and pumped hydro energy storage-solar photovoltaic hybrid systems 5.3.2 Other cases of pumped hydro energy storage system 5.4 Future hybrid pumped hydro energy storage systems 5.4.1 Case study 1: Pumped hydro energy storage coupled with the onshore wind in Gaildorf Germany 5.4.2 Case study 2: Pumped hydro energy storage coupled with solar photovoltaic technology, Hatta, United Arab Emirates 5.4.3 Case study 3: Pumped hydro energy storage coupled with floating solar photovoltaic technology, Kruonis, Lithuania 5.4.4 Case study 4: Pumped hydro energy storage coupled with solar photovoltaic technology in the Atacama Desert, Chile 5.4.5 Case study 5: Pumped hydro energy storage coupled with wind and solar photovoltaic technology, Kidston, Australia 5.5 Conclusion References

6. Concept for cost-effective pumped hydro energy storage system for developing countries

73 75 75 77 78 80 80 81 84 84 85 85 85 86 86 87

89

Emmanuel Yeboah Asuamah, Williams Amankwah, Mathew Atinsia Anabadongo, Martin Kyereh Domfeh and Felix A. Diawuo 6.1 6.2 6.3 6.4

Introduction Overview of cost-effective analysis Project viability factors Financial and economic assessment indices of pumped hydro energy storage projects 6.4.1 Performance metrics for determining cost-effectiveness of pumped hydro energy storage plants 6.4.2 Cost comparison of energy storage technologies based on decision maker’s definition of cost-effectiveness 6.4.3 Pumped hydro energy storage financing models

89 91 91 92 93 95 96

viii

Contents

6.4.4 Issues related to pumped hydro energy storage financing and the way forward 6.5 Conclusion References

7. Technological advances in prospecting sites for pumped hydro energy storage

101 101 102

105

Komlavi Akpoti, Salomon Obahoundje, Eric M. Mortey, Felix A. Diawuo, Eric O. Antwi, Samuel Gyamfi, Martin Kyereh Domfeh and Amos T. Kabo-bah 7.1 Introduction 7.2 Pumped hydro energy storage 7.3 Potential sites for pumped hydroelectric energy storage 7.3.1 Traditional (conventional) river-based pumped hydroelectric energy storage 7.3.2 Off-river (closed-loop) pumped hydro systems 7.4 Factors to consider in the pumped hydroelectric energy storage site selection 7.4.1 Geographic and engineering factors 7.4.2 Environmental factors 7.4.3 Economic factors 7.4.4 Social factors 7.5 Models for pumped hydroelectric energy storage suitability modeling/mapping 7.6 Environmental impacts of pumped hydroelectric energy storage on prospective sites 7.6.1 Land requirements 7.6.2 Water requirements 7.6.3 Impact on fishery industry and aquatic habitat 7.6.4 Cultural, historical, and scenery impacts 7.6.5 Other environmental factors 7.7 Addressing the environmental impacts 7.8 Conclusion References

8. Techno-economic challenges of pumped hydro energy storage

106 107 109 109 109 109 109 110 111 112 112 115 115 115 115 116 116 116 117 117

119

Samuel Gyamfi, Emmanuel Yeboah Asuamah and John Ansu Gyabaah 8.1 Introduction 8.2 Overview of pumped hydro energy storage 8.3 The main driver for some existing pumped hydro energy storage plants

119 121 123

Contents

8.3.1 Europe 8.3.2 Japan 8.3.3 China 8.3.4 United States 8.3.5 India 8.4 Barriers to deployment 8.4.1 Technical and geographical barriers 8.4.2 Economic barriers 8.4.3 Unfavorable policies for pumped hydro energy storage in the electricity market 8.4.4 Environmental barriers 8.4.5 Other barriers 8.5 The way forward 8.6 Conclusion References

9. Lessons for pumped hydro energy storage systems uptake

ix 123 124 124 125 125 125 126 126 128 130 131 131 133 133

137

Martin Kyereh Domfeh, Felix A. Diawuo, Komlavi Akpoti, Eric O. Antwi and Amos T. Kabo-bah 9.1 9.2 9.3 9.4 9.5

Introduction Classifications of pumped hydro energy storage Site considerations for pumped hydro energy storage development Climate change impact on pumped hydro energy storage Drivers and barriers to pumped hydro energy storage 9.5.1 Classification of pumped hydro energy storage drivers 9.5.2 Classification of pumped hydro energy storage barriers 9.6 Market overview and future trends of pumped hydro energy storage 9.6.1 Financial and economic assessment indices of pumped hydro energy storage projects 9.6.2 Pumped hydro energy storage financing models 9.7 Key factors for pumped hydro energy storage uptake 9.7.1 Investing in public-private research, development and deployment 9.7.2 Instituting regulatory frameworks that stimulate innovative operation of pumped hydro energy storage 9.7.3 Increasing digital operation of pumped hydro energy storage systems 9.7.4 Retrofitting pumped hydro energy storage facilities 9.8 Conclusion References Index

137 139 140 141 141 141 144 148 148 149 149 149 150 150 151 151 151 155

This page intentionally left blank

List of contributors Komlavi Akpoti Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; International Water Management Institute (IWMI), Accra, Ghana Williams Amankwah Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana Roland Teye Amanor Department of Chemical Engineering, Budapest University of Technology and Economics, Budapest, Hungary Mathew Atinsia Anabadongo Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana Eric O. Antwi Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; Department of Civil and Environmental Engineering, School of Engineering, UENR, Sunyani, Ghana Emmanuel Yeboah Asuamah Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; School of Energy, UENR, Sunyani, Ghana Mathew Anabadongo Atinsia Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; School of Energy, UENR, Sunyani, Ghana M.A.A. Derkyi School of Energy, Department of Renewable Energy Engineering, UENR, Sunyani, Ghana N.S.A. Derkyi School of Energy, Department of Renewable Energy Engineering, UENR, Sunyani, Ghana Felix A. Diawuo Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; School of Energy, UENR, Sunyani, Ghana; Renewable Energy Engineering Department, UENR, Sunyani, Ghana Martin Kyereh Domfeh Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; Earth Observation Research and Innovation Center (EORIC), UENR, Sunyani, Ghana; Department of Civil and Environmental Engineering, School of Engineering, UENR, Sunyani, Ghana; School of Energy, Department of Renewable Energy Engineering, UENR, Sunyani, Ghana

xi

xii

List of contributors

John Ansu Gyabaah Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; School of Energy, UENR, Sunyani, Ghana Samuel Gyamfi Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; School of Energy, UENR, Sunyani, Ghana Amos T. Kabo-bah Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana; Earth Observation Research and Innovation Center (EORIC), UENR, Sunyani, Ghana; Department of Civil and Environmental Engineering, School of Engineering, UENR, Sunyani, Ghana Ebenezer Nyarko Kumi Department of Mechanical and Manufacturing Engineering, UENR, Sunyani, Ghana; Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana J.Y. Kusi Ho Technical University, Ho, Ghana Eric M. Mortey Earth Observation Research and Innovation Centre (EORIC), UENR, Sunyani, Ghana; Faculty of Science and Techniques, Doctoral Research Program in Climate Change and Energy (DRP-CCE) of the West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), Université Abdou Moumouni, Niamey, Niger Salomon Obahoundje LASMES-African Centre of Excellence on Climate Change, Biodiversity and Sustainable Development, Université Félix Houphouët Boigny, Abidjan, Ivory Coast; International Joint Laboratory on Climate, Water, Agriculture, and Energy Nexus and Climates Services (LMI NEXUS), Université Félix Houphouët Boigny, Bingerville, Ivory Coast

Foreword Coming from a country that has increasingly felt the brunt of the effects of climate change, such as flood events and heat waves, it is difficult not to be excited at the mention of any possible solution to climate change problems. The floods and heat waves, which have recently become even much more frequent, are linked with increased warming of the earth’s climate, which, in turn, is due to an increase in the concentration of atmospheric carbon dioxide (CO2) in the atmosphere, which forms a blanket in the atmosphere, holding in heat, and thus warming the planet. The burning of fossil fuels is one of the chief contributors of CO2 in the atmosphere. When fossil fuels, which consist mainly of carbon and hydrogen, are burnt, the carbon reacts with the oxygen in the air to form CO2, while hydrogen combines with oxygen to form water. Unfortunately, up to 63% of our energy is generated by burning fossil fuels (especially natural gas and coal), one of the major causes of climate change and global warming. Therefore any opportunity to bring in alternatives to the present energy supply sources should be welcomed with great excitement, and that is what this book is about. In this book, experts in energy and environmental engineering research, who are very knowledgeable about alternative sources of energy, especially renewable energy, extensively discuss practical ways by which renewable energy sources could be incorporated into the electrical grid. Until recently, there had been a reluctance shown by a part of the electrical-production community towards incorporating renewable energy sources into the power grid. This is mainly because of the variable nature of the energy generated by renewable energy sources, especially wind and solar energy. The quantity of energy they generate throughout the day varies and is also affected by seasonal variations. This implies that to make optimum use of these renewable sources, one would have to store the energy generated at peak times for use in off-peak seasons. However, fossil fuels are capable of meeting the energy demands almost instantaneously, and the current electrical grids are built to be suitable for renewable energy sources. Could this be the reason why there is a general reluctance to transit from fossil fuel energy sources to renewable energy sources? Fortunately, energy storage systems have come into existence and are continuously being researched for further improvements. xiii

xiv

Foreword

Electrical energy storage systems can be used to incorporate renewable energy sources into power grids. These systems consist of a unit for storing the energy and another for converting power. The energy storage unit of the system is operated by the direct current voltages, in conjunction with an inverter, and transforms the direct current into alternating current. This alternating power can then be added to the grid with the help of an alternating current transmission system. Some electrical energy storage systems make use of rectifiers to convert the alternating current into direct current for the storage systems. These energy storage systems can make power grids suitable for operation with renewable energy sources. Based on their performance, energy storage systems can improve the efficiency of the electric grid. One of the ways by which they improve the grid’s efficiency is by storing energy. This helps ensure the baseload power is put to use efficiently, especially during off-peak periods, thus reducing the cost of power generation significantly. Additionally, the introduction of energy storage systems in power grids facilitates the supply of electricity to customers located far away from the power grid. Electricity, which is usually generated far away from urban areas, experiences losses during transmission. Sometimes, the load demand or the generated power exceeds the grid’s transmission capacity. This leads to either curtailment of excess energy or a need to improve the grid’s system to accommodate the changes. However, with energy storage systems incorporated into the grid, it will be possible to store the excess generated energy, so that it can be returned to the grid when the delivery capability is restored. Also, when there is an increase in demand, the presence of energy storage systems reduces the burden on the transmission lines, as the delivery of power will simply be shifted from on-peak to off-peak times. This would help improve the utilization factor of the power grid, preventing the need for frequent upgrades. Despite the many advantages of energy storage systems, only a handful of countries are implementing these systems in their power generation and supply. Not surprisingly, countries with a high implementation of energy storage systems in power grids have recorded a steady generation and supply of energy. For instance, China has the highest installed capacity, and most of its installed capacity comes from pumped hydrogen storage. Pumped hydroenergy storage system is one of the most widely used energy storage systems. It is a large-scale energy storage system that can provide capacity enhancing the daily capacity factor of the grid. This commercially available technological system makes use of two water reservoirs at different heights

Foreword

xv

for storing and generating power, and accounts for more than 99% of the installed energy storage system capacity. The possibility of incorporating energy storage systems into electrical grids is being increasingly researched, and systems like pumped hydroenergy storage system have already been implemented in many countries. However, the implementation of this technology is not yet as widespread as expected, considering its numerous benefits. Therefore this book enlightens the reader on energy storage systems. This book discusses what energy storage systems are and also elucidates upon the wide range of grid services they can provide. It extensively discusses the concept, history, and global perspectives of energy storage systems. Finally, it introduces the pumped hydroenergy storage system, which has the potential to aid grid operational flexibility, stability, cost-effectiveness, and, most importantly, supports the deployment of other renewable sources such as solar and wind. In essence, this book is highly recommended for energy economists, energy managers, engineers, designers, policy and decision makers, corporate planners, energy industries, and students enrolled in energy-related courses. Academic and research scientists will also greatly benefit from reading this book, as it gives a detailed account of the progress made so far in the development of energy storage systems. This book will give them a fair idea of research areas yet to be explored. There is still enough room available for the improvement of the already existing systems, especially in coming up with cost-effective and yet utility-scale alternatives. Furthermore, this book will be of great benefit to electricity authorities and decision makers, facilitating them in making informed choices on improving their country’s/organization’s electrical energy generation system. Based on information gathered from this book, they will be able to figure out which energy storage system will be best suited to meet their community/organization’s needs. In all, this book is key for everybody, and is a must-read for anyone who would like to make a career in any energy-related field in the 21st century. There is an ongoing paradigm shift towards the generation of environmentally friendly energy systems and you wouldn’t want to be left behind. Anthony Boye Osafo-Kissi Former Deputy CEO, Bui Power Authority, Accra, Ghana

This page intentionally left blank

Preface Advancements in technology and population explosion have led to an unprecedented growth in the world’s energy demand. To meet this increasing energy demand, fossil fuel reserves are being rapidly depleted, especially coal, gas, and oil, which have been the most utilized fuels until now. So, there is an urgent need of finding alternative sources of energy before the fossil fuel reserves run out completely. Moreover, societies also have an important role to play here through transforming ways of generating and consuming energy in the face of severe threats posed by combustion of fossil fuels, for example, anthropogenic climate change. As a result of all these, research on alternative energy sources has gained momentum. These include solar photovoltaic, solar thermal, wind power energy, geothermal power energy, hydroelectric, biofuels, biomass, and tidal energy. Of all these energy sources, wind and solar energy are increasingly being explored and utilized because of their commercial acceptance and technological advancements. Unfortunately, there are some limitations associated with the use of renewable energy sources, especially solar and wind energy. For example, the power grid continuously produces electrical power to meet the energy demand constantly, whereas solar and wind power sources are not available throughout the day and are affected by day-to-day seasonal variabilities. For example, in Texas, where the use of air-conditioners consume a large share of energy demand, it was observed during one early evening in the month of August that heavy usage of air-conditioning systems placed a high demand of electricity. However, at that time of the day, there was no solar power and the weak wind currents could generate very little electricity as compared to the demand. To overcome such problems, energy storage systems have been developed. Energy storage systems consist of systems that can store energy safely for use when needed. These systems are very crucial to the operation of power systems, as they help achieve continuity of the power supply, and improve the system’s reliability, efficiency, and cost of operation. Moreover, the use of energy storage systems reduces transmission curtailment and transmission and distribution deferrals. By so doing, it becomes possible to produce and distribute electricity to consumers located far from the grid. Several types of energy storage systems have been xvii

xviii

Preface

developed, depending on the type of use, initial capital requirement, operational cost, and the system’s required capacity. In addition to these considerations, researchers are also paying attention to developing energy storage systems that are largely environmentally friendly. Generally, energy storage systems can be classified based on several factors. The form of the energy to be stored determines the cost, size, and scalability of the energy storage system. While some forms of energy storage like chemical batteries in wristwatches or computers are better suited for small-scale applications, others such as pumped hydropower storage can only be used for large-scale applications. Based on the type of storage, energy storage systems can be classified into four main categories: • Mechanical energy storage: pumped hydro storage, compressed air energy storage, and flywheel energy storage. • Electrochemical energy storage: battery storage, capacitor storage, and electromagnetic energy storage (SMES). • Chemical energy storage: hydrogen storage (hydrogen gas etc.) and biofuel. • Thermal energy storage: sensible heat storage and latent heat storage. Of all these several types of energy storage systems, pumped hydro energy storage (PHES) has been the most commonly used energy storage system. As of 2018, energy storage systems had been capable of generating 175,823 MW of energy. Of this, PHES accounted for 169 557 MW, which is approximately 96% of the total energy produced by energy storage systems installed globally. PHES is used for utility-scale electricity storage because of its operational flexibility, grid stability, costeffectiveness, and support for the deployment of other renewable sources such as solar and wind. This book provides useful insight into the need and use of PHES in the electrical power systems of today and the future. In this book, PHES is considered to be a critical component of the electricity system, which plays several roles, depending on the economic, environmental, and technical conditions. Only a homogeneous storage rumination will lead to accurate and veritable placement of energy storage systems in future electrical systems. PHES can help achieve the goals related to climate change and energy security by delivering valuable services in energy systems of the present and future. This systematic approach to energy system design can lead to the development of an energy system that is more integrated and optimized to play a critical role in energy decarbonization and become part of the global pathway to net-zero emissions by 2050.

Preface

xix

The book is organized as follows: Chapter 1 looks at energy storage systems where the methods and techniques of storing energy are discussed. The criteria for selecting a particular storage system such as energy requirement, energy storage efficiency, storage cost, storage infrastructure, and other factors are presented. Some of the main energy storage techniques available and discussed include electrochemical systems such as batteries and supercapacitors; mechanical systems such as flywheels; pneumatic systems such as air compressors; and hydro systems such as PHES. Chapter 2 systematically presents the importance of PHES and its role in load balancing, peak load shaving, grid stability, etc. It additionally discusses the important role of PHES in deploying hybrid systems. Chapter 3 describes the different PHES schemes while looking at their main features, performance characteristics, commercial maturity, cost, and other operational characteristics. The chapter further discusses the advantages and disadvantages of PHES and issues of sustainability in relation to its application. Chapter 4 broadly presents the existing market structure for PHES and how the market responds to the scheme of pricing relative to the levelized cost of supplying electricity from PHES. Chapter 5 provides some applications of PHES and its integration with other intermittent renewable energy sources such as solar and wind. The chapter also looks at hybrid PHES configurations and presents some existing and future case studies. Most of the hybrid PHES case studies presented are largely centered on photovoltaic (PV) PHES hybrid systems, PHES wind hybrid systems, and PHES PV wind hybrid systems. Chapter 6 broadly looks at the economic indicators needed in the assessment of PHES such as net present cost (NPC), net present value (NPV), levelized cost of energy or electricity (LCOE), pay back period, internal rate of return (IRR), avoided cost of energy, and benefit cost ratio. It presents an economic analysis according to different concepts and defines economic indexes. Further, the existing financing models available for PHES projects are also discussed. Chapter 7 looks at the technological advancements in prospecting sites for PHES where contents relating to design parameters for PHES, factors considered in selecting PHES sites, environmental impacts of PHES prospecting sites, and others are discussed. Chapter 8 focuses on technological, economic, social, and regulatory barriers toward the deployment of PHES at various utility scales and Chapter 9 subsequently discusses the way forward to addressing the challenges in order to boost its deployment.

xx

Preface

The era of rhetoric and the business-as-usual approach toward energy planning is long gone, and, therefore, decision makers must realize that long-term planning goes far beyond the abrupt concerns of quarterly and/or annual reports and legislative periods. In this generation of substitute facts and fictitious news, this book is intended to provide a solid basis for cogent policy deliberations. We anticipate that this book will serve as a valuable resource for a variety of people, including policy/decision makers, engineers, developers, practitioners, academics researchers, and students who are involved in the ongoing global energy transition and those who need a reference on the subject relating to PHES. Amos T. Kabo-bah Felix A. Diawuo Eric O. Antwi

Acknowledgments We are indebted to the Almighty God for good health and knowledge to edit this valuable piece of work. We are grateful to the authors and anonymous reviewers for their related criticisms, suggestions, and comments on various chapters. We are also grateful to the School of Energy and the Regional Centre for Energy and Environmental Sustainability (RCEES) at the University of Energy and Natural Resources (UENR), Energy Commission of Ghana, Bui Power Authority and Instituto Superior Técnico, and Universidade de Lisboa for the technical support provided throughout the writing phase of the book. We will be eternally thankful to all prospective readers, scholars, researchers, and engineers who would take some time off to read these valuable chapters. We believe that each chapter would help shape our minds and attitude towards creating a renewable energy mix system for meeting the ever-growing demands of energy in Africa and the rest of the world. Finally, we are grateful to our families, Kabo-Bah's, Diawuo's, and Antwi’s, for the valuable resource support and companionship during the whole phase of editing and putting up this book. Amos T. Kabo-bah Felix A. Diawuo Eric O. Antwi

xxi

This page intentionally left blank

CHAPTER 1

Energy storage technologies Ebenezer Nyarko Kumi1,2 1

Department of Mechanical and Manufacturing Engineering, UENR, Sunyani, Ghana Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana

2

Contents 1.1 Introduction 1.2 Energy storage classifications 1.2.1 Mechanical energy storage systems 1.2.2 Thermal storage systems 1.2.3 Chemical energy storage 1.2.4 Electrochemical energy storage 1.2.5 Electrical energy storage 1.3 Emerging energy storage technologies 1.3.1 Tesla powerwall and powerpack 1.3.2 Vanadium redox-flow battery 1.3.3 Solid-state batteries 1.4 Case study applications of energy storage solutions 1.4.1 Off-grid school lighting in Angola 1.4.2 Off-grid frequency response in Alaska 1.4.3 Time shift and ancillary services case study in China 1.5 Barriers and challenges in energy storage technologies 1.5.1 Cost 1.5.2 Market risk and business model 1.5.3 Modeling challenges 1.5.4 Technology risk 1.5.5 Regulatory barriers 1.6 Conclusions References

1 2 4 8 9 11 13 14 15 15 16 16 16 17 17 18 18 18 19 19 19 20 20

1.1 Introduction Energy storage technologies are critical components of contemporary electrical power networks, with uses in both traditional and renewable energy. The main uses of energy storage systems include balancing the changing load impacts of renewable energies, offering extra services such

Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00002-9

© 2023 Elsevier Inc. All rights reserved.

1

2

Pumped Hydro Energy Storage for Hybrid Systems

as frequency and voltage stability, maintaining a stable energy supply, and increasing dependability and spread. It provides a lot of cost savings to the electricity grids as well as firms deploying storage technology. Large-scale energy storage also enables modern electrical systems to work more effectively, and higher efficiency implies cheaper prices, reduced emissions, and more stable electricity. Energy storage may be a critical aspect in enabling effective renewable energy integration and reaping the benefits of local generation and a clean, reliable energy supply. The technology continues to prove its relevance to grid operators worldwide that must manage intermittent energy generation from wind and solar. In the absence of energy storage devices, power supply issues such as abrupt blackouts might arise because of unstable sunlight-dependent electricity supply in the case of solar electricity generation. With global energy consumption expected to double by 2050 and triple by the end of the century, minor modifications to existing networks will be unable to service this vast demand in a sustainable manner (IRENA, 2018). Despite significant gains in renewable energy generation in recent years, finding adequate supply of clean energy for the future remains one of society’s most difficult challenges. With the increase in renewable energy production, there comes the urgent need for energy storage techniques for this energy. It is a critical component in the integration of renewable energy sources, as well as in maintaining a stable and dependable modern energy system. Conventional energy sources, including coal and other crude oil-based plants, must be turned on and off as demand changes, and almost never operate at peak efficiency. Energy storage systems are primarily used to offer electrical energy decoupling between the supply and demand sides, with the goal of constantly ensuring stable power. Demand-side management refers to power balancing methods used on the load side.

1.2 Energy storage classifications Energy storage solutions include a wide range of systems that could be divided into five major categories:mechanical, thermal, chemical, electrochemical, and electrical storage technologies illustrated in Fig. 1.1 (India Energy Storage Alliance (IESA), 2020). These technologies include capacitors (often referred to as electrostatic storage systems), inductors (also known as electrodynamic magnetic storage systems), as well as thermal storage technologies that may store electricity directly for relatively short periods of time using heating resistors as electro-thermal converters; steam turbines

Energy storage technologies

3

Figure 1.1 Energy storage system classifications (Larsen & Sønderberg Petersen, 2013).

that convert thermal energy into electricity, despite significant efficiency losses in the overall process; electrochemical storage which predominantly covers different battery technologies; chemical storage technologies that use electricity to produce hydrogen for energy storage purposes; fuel cells that, in turn, convert the stored energy back to electricity utilizing hydrogen as fuel. Kinetic energy in flywheels and potential energy in pumped storage hydroelectric systems (PSH) make use of electromechanical converters such as motors, pumps, turbines, and generators to store and release energy accordingly. Another type of mechanical energy storage in the form of potential energy is compressed air energy storage (CAES). Electricity may be stored in thermal energy storage devices for a limited time and can be used for hot water, space heating, or as a thermal

4

Pumped Hydro Energy Storage for Hybrid Systems

agent for industrial processes. The reverse recovery of the heat into electricity, however, has extremely poor efficiency and is not popularly employed in industrial applications. An invention known as pumped heat electricity storage has the potential to improve the status of nonreversible heat storage systems (Roskosch & Atakan, 2017). As a massively invertible gas cycle machine, it may function as a heat engine or a heat pump. This storage system consists of two enormous vessels that store cold and heat in gravel as the storage medium, resulting in a cold and hot container. The heat is then transferred from one vessel to the other using electricity (National Renewable Energy Laboratory NREL, n.d.). This technology is promising and offers a wide range of applications with high efficiency at cheap prices. The growing need for energy storage is further heightened by the fact that as projections of the output of wind and solar power get more exact, these forecast errors become more visible by their very nature. Electricity storage technologies are getting to a point where they may have an impact on markets. To meet these demands, storage engineers are continuing to develop a wide range of possible solutions, including kinetic, electrochemical, and thermal technologies. Each of these categories is now in use in the commercial sector and offers potential grid-scale solution in the future. Energy storage solutions are categorized based on their storage capacity and operational timeframe (Fig. 1.2).

1.2.1 Mechanical energy storage systems Mechanical energy storage uses heat, water, or air in conjunction with compressors, turbines, as well as other equipments to provide reliable energy storage alternatives. Although the basics of these storage systems are quite simple, the technologies that support the effective and efficient utilization of these energy sources are highly sophisticated, necessitating the adoption of complicated novel designs to make these systems viable in practical systems. Pumped storage hydropower, compressed air storage, and flywheels are examples of storage systems for mechanical energy. 1.2.1.1 Pumped storage hydropower Pumped storage hydropower systems store excess electrical energy by harnessing the potential energy stored in water. Fig. 1.3 depicts PSH, in which surplus energy is used to move water from a lower reservoir to a higher reservoir. Once electricity demand increases, the water from the higher reservoir is discharged through turbines to create electricity, exactly

Energy storage technologies

5

Figure 1.2 Categorization of energy storage solutions using storage capacity and operational timeframe (Larsen & Sønderberg Petersen, 2013; Rastler, 2010).

Figure 1.3 Principle of pumped storage hydropower (Nikolaidis & Poullikkas, 2017).

6

Pumped Hydro Energy Storage for Hybrid Systems

like a typical hydropower plant. Energy may be released on demand and turned into electrical power in a short amount of time. PSH has the potential to balance demand and supply by narrowing the difference between peak and off-peak times, levelling other generating units, and safeguarding the power system. PSH has a roundtrip efficiency of 70% to 80%. The lifespan of PSH is projected to be between 40 and 60 years. 1.2.1.2 Compressed air energy storage CAES, like PSH, uses excess electricity to fill a physical reservoir. Fig. 1.4 depicts compressed air being utilized to fill the reservoir, which is often an underground cavern, which is subsequently released to power turbines. In the few commercial implementations of CAES to date, stored air is released and combined with natural gas to produce power. Researchers are working on CAES without the use of hydrocarbons, as well as more efficient heating and pressurization systems, although this technique has not yet been commercialized. 1.2.1.3 Flywheel energy storage Flywheel energy storage (FES) devices, which generally operate in a vacuum, store energy as kinetic energy in a high-speed rotor coupled to either a motor or generator (Brown & Chvala, 2009). Flywheels, as seen

Figure 1.4 Illustration of compressed air energy storage (Donadei & Schneider, 2016).

Energy storage technologies

7

Figure 1.5 Flywheel energy storage (Luo, Wang, Dooner, & Clarke, 2015).

in Fig. 1.5, are composed of a rotating mass that is propelled by a motor, and when demand for energy increases, the rotational force drives a device similar to a turbine to generate power. Electricity is converted into kinetic energy using FES systems. Kinetic energy can be described as energy in motion, especially the motion of a rotating object known as a rotor spin in a virtually frictionless environment. In discharge mode, the flywheels decelerate and are perfect for short-duration, fast-response backup power. The notable advantages of flywheel storage include the following: 1. High power density: This is most distinctive advantage. They may be charged at extremely high rates and give extremely high powers. This feature of flywheels is exploited fully in some machines that need short bursts of high power. One of the promised applications is fast battery charging. 2. Non-polluting: Another advantage of FESs is their absence of pollution of all forms: chemical, thermal, or acoustical. The only instances at which flywheels can cause pollution are during their construction, in the case where some plastics are used. 3. High efficiency: The flywheel has a very high efficiency, especially when used for short-time storage. In advanced systems where magnetic bearings are employed, the systems can maintain high efficiencies for longer periods although such systems have not yet been developed to an operational stage. 4. Long life: A 20-year operating life and thousands of charge/discharge cycles can be expected. 5. Climate/weather: Flywheels are unaffected by extreme conditions

8

Pumped Hydro Energy Storage for Hybrid Systems

1.2.2 Thermal storage systems Thermal energy storage is the process of storing heat utilizing various technologies for use in heating, cooling, and power production applications. Water, bedrock, deep aquifers, thin-walled pits filled with water and gravels with insulations at the top, as well as eutectic solutions and phase-change materials are examples of heat storage media. In general, heat storage may be classified into sensible heat storage (SHS), phase change (latent heat) storage (LHS), and chemical reaction storage (thermochemical). 1.2.2.1 Sensible heat storage The simplest method of storing heat energy is by sensible heat, which involves heating or chilling a solid or liquid storage medium such as rocks, sand, water, or molten salts. The most widely used heat storage medium is also commercially accessible, having a several domestic and commercial application. Large-scale applications also make use of underground heat storage in both liquid and solid mediums. SHS is inexpensive and avoids the hazards associated with the use of toxic chemicals. SHS makes use of the change in temperature as well as the heat capacity of the storage medium in determining the quantity of heat stored. 1.2.2.2 Latent heat storage In LHS, a considerable portion of the collected heat is discharged or taken up during the change of phase of the heat storage medium. A phase change medium is able to absorb and release energy with a change in its physical state. In the case of LHS, the energy storage density improves with a decrease in the volume of the system. The high energy density of the LHS system, as well as the isothermal nature of the storage process, makes it an effective method of storing heat. The ability to retain heat at nearly comparable temperature ranges is the primary advantage of LHS over SHS. Initially, these materials behave like standard SHS media seeing as how the temperature rises linearly with the system enthalpy; however, when the physical state changes, heat is absorbed or released at virtually constant temperature. The heat absorption or release that happens as a storage media transits from one phase to the other. 1.2.2.3 Thermochemical energy storage Thermochemical heat storage works on the notion that all chemical reactions either absorb or release heat; hence, a reversible process that absorbs

Energy storage technologies

9

heat while running in one way would release heat when running in the other direction. Thermochemical energy storage stores energy by using a high-energy chemical process. Heat is applied to material A during the charging process, resulting in the separation of two portions, B and C. The resulting reaction products are readily isolated and kept until the discharge procedure is required. The two portions B and C are subsequently combined under optimal pressure and temperature conditions, resulting in the release of energy. Heat losses from storage units are limited to sensible heat effects, which are often negligible in comparison to the heat of reaction. The thermal breakdown of metal oxides has been researched for energy storage applications. These reactions may be advantageous since the emitted oxygen could be reused or disposed of and the oxygen from the atmosphere could be utilized in the reverse operations. Potassium oxide decomposes at temperatures between 300°C and 800°C while releasing 2.1 MJ/kg of heat in the process, whereas lead oxide, on the other hand, decomposes at temperatures between 300°C and 350°C, releasing 0.26 MJ/kg of heat in the process (Sarbu & Sebarchievici, 2018).

1.2.3 Chemical energy storage Chemical energy is held in chemical compound bonds and may be released during chemical processes, notably as heat. The common forms of chemical energy discussed are stored in hydrogen, hydrocarbons, and ammonia. 1.2.3.1 Hydrogen Hydrogen is a vital enabler for the advancement of fuel cell technology in areas such as electricity production and transportation. Despite having the highest energy density per unit mass than any fuel, hydrogen has the lowest energy density per unit volume owing to its low ambient temperature, necessitating the development of innovative storage methods with the potentially higher energy density (Osman et al., 2021). Hydrogen generated from the electrolysis of water can be stored for later use as feedstock for ammonia and other chemicals, as well as a direct process heat fuel. The stored hydrogen can be burned in a turbine or combined with oxygen in a fuel cell to generate electricity. Hydrogen storage as illustrated in Fig. 1.6 involves either the physical storage in the form of gas or liquid or combined with other materials.

10

Pumped Hydro Energy Storage for Hybrid Systems

Figure 1.6 Various forms of hydrogen storage (Department of Energy, n.d.).

1.2.3.2 Hydrocarbons Hydrocarbons are organic, chemical molecules that occur spontaneously and are mostly made of hydrogen and carbon atoms. However, when hydrocarbons are discharged into the environment, they can pose a number of health risks (Perera, 2018). Their highly flammable nature, toxicity, and widespread distribution as greenhouse gases endanger humans and the environment. It is for these reasons that adequate storage of hydrocarbons must be addressed when working with them. 1.2.3.3 Ammonia Ammonia is held in a tank and converted to electricity as needed, either using standard combustion techniques or by breaking it into nitrogen and hydrogen (Fig. 1.7). Ammonia, like fossil fuels, is both a chemical energy storage system and a fuel, releasing energy through the formation and breakdown of chemical bonds (Valera-Medina, Xiao, Owen-Jones, David, & Bowen, 2018). The net energy gain for ammonia is due to the

Energy storage technologies

11

Figure 1.7 Generation of electricity from ammonia (Lovegrove, Lavine, Aryafar, & Chen, n.d.).

breakdown of nitrogen hydrogen bonds, which results in the formation of nitrogen and water when mixed with oxygen. Ammonia, which is usually stored in a tank, can be converted to electricity either through combustion or by splitting it into nitrogen and hydrogen. The hydrogen produced in the latter approach may subsequently be utilized in hydrogen fuel cells to power devices such as electric vehicles.

1.2.4 Electrochemical energy storage Electrochemical energy storage includes various types of secondary batteries in which the oxidation-reduction reversal process, which transforms the chemical energy in its active components into electrical energy (Krivik & Baca, 2013). Examples of these include standard batteries such as lead-acid and nickel-cadmium; modern batteries including lithium-ion, lithium polymer, and nickel metal hydrides; special batteries such as silverzinc and nickel hydrogen; flow batteries including vanadium flow and zinc-bromide as well as high temperature batteries including sodiummetal chloride and sodium-sulfur. These examples fall under two categories of batteries: secondary and flow.

12

Pumped Hydro Energy Storage for Hybrid Systems

1.2.4.1 Secondary batteries Secondary batteries can be recharged by sending an electric current to the cell, which reverses the chemical reactions (Luo et al., 2015). The original chemical reactants are regenerated, allowing them to be used, recharged, and reused several times. Due to active material dissipation, electrolyte loss, and internal corrosion, secondary batteries do not appear to be eternally rechargeable. For many individuals, it is pretty straightforward; limit energy consumption from the power grid and store alternative energy for later use; nonetheless, there are other strong reasons stated below. 1. Reduce energy costs by using less grid electricity. 2. Reduce pollution from coal/nuclear/gas power generation through lowering emissions. 3. Have electricity available in the event of a power outage or an emergency. 4. Become self-sufficient in terms of energy by operating off-grid whenever possible. 5. Reduce peak consumption through peak lopping and grid optimization. 1.2.4.2 Flow batteries Flow batteries, like ordinary batteries and fuel cells, are electrochemical devices that directly convert the chemical energy in electroactive materials directly into electricity (Nguyen & Savinell, 2010). A flow battery produces chemical energy by mixing two chemical constituents that are dissolved in liquids contained within the device with a membrane separating them. Ion exchange occurs via the membrane, accompanied by the passage of an electric current, while both liquids circulate at their own speeds. The electrolytes are kept in external reservoirs before being allowed to flow through the cell, which directly transforms its energy to electricity. Redox-flow batteries and hybrid flow batteries (HFBs) are the two types of flow batteries. In redox-flow batteries, two electrolyte solutions referred to as catholyte and anolyte are forced to opposing ends of an electrochemical cell as shown in Fig. 1.8. Anolyte and catholyte flow between permeable electrodes is separated by a membrane that permits protons to pass through while electron transfer occurs. In a HFB, one of the active masses is kept within the electrochemical cell, while the other is kept in the electrolyte and stored outside in a tank (Badwal, Giddey, Munnings, Bhatt, & Hollenkamp, 2014). As a consequence, HFB cells contain features of both typical secondary batteries and redox-flow batteries: the capacity of the battery is governed by the size of the electrochemical cell. Zn-Ce and Zn-Br systems are two examples of HFBs.

Energy storage technologies

13

Figure 1.8 Redox-flow battery schematic (Nguyen & Savinell, 2010).

1.2.5 Electrical energy storage Electrical energy storage (EES) serves three purposes: it lowers cost of power supply by storing electricity at off-peak rates, it improves dependability in the event of unforeseen breakdowns or disasters, and it maintains and improves power quality (frequency and voltage) (Giddey, Badwal, & Ju, 2018). The two forms of EES systems include supercapacitors (electric double-layer capacitor) and superconducting magnetic energy storage (SMES). 1.2.5.1 Electric double-layer capacitor Supercapacitors, also known as electric double-layer capacitors, are energy storage devices with a higher energy density than standard capacitors and batteries. A double-layer capacitor has a higher electric capacity than a conventional capacitor because an electric double layer, which is a layer with the opposite polarity to the electrode, is generated around the electrolyte’s

14

Pumped Hydro Energy Storage for Hybrid Systems

Figure 1.9 Electric double-layer capacitor (Energy Systems & Energy Storage Lab, n.d.).

electrode (Energy Systems & Energy Storage Lab, n.d.). It offers excellent high-current charge/discharge and repeating cycle properties, just like conventional capacitors. Fig. 1.9 illustrates an EES device that relies on a charge-discharge process in a supercapacitor on a porous electrode. 1.2.5.2 Superconducting magnetic energy storage Superconducting magnetic energy storage stores electrical energy in a magnetic field. As illustrated in Fig. 1.10, a direct current going through a superconducting coil generates this magnetic field. As electricity travels via a typical wire, some energy is wasted owing to electric resistance. In SMES systems, however, the wire is constructed of superconducting material that has been cryogenically chilled to its critical temperature. Mercury, vanadium, and niobium-titanium are examples of common superconducting materials.

1.3 Emerging energy storage technologies One of the main limitations of solar and wind power is that there is no control over when the system will be producing energy. To get a constant power output from a solar or wind power system, it is required to size the system larger and to store the surplus energy for when it is needed. The electrical grid is a complicated system that demands equal power supply and demand at all times, which is why feasible storage technologies are being developed to assist power use. To ensure stability, the grid must be constantly adjusted, and effective storage will play a vital part in the essential balancing act, providing the system with more flexibility and

Energy storage technologies

15

Figure 1.10 Superconducting magnetic energy storage (Nikolaidis & Poullikkas, 2017).

resilience. Some emerging technologies that could become viable energy storage solutions for renewable energy include the following: 1. Tesla Powerwall/Powerpack 2. Vanadium redox-flow battery 3. Solid-state batteries

1.3.1 Tesla powerwall and powerpack The Tesla Powerwall is a stationary rechargeable lithium-ion battery designed for household energy storage. It may be used for solar self-consumption, timeof-use load management, backup systems, and off-grid use (Clean Technical, 2020). The Powerpack, on the other hand, is designed for commercial or electric utility grid applications such as peak shaving, load management, backup systems, microgrids, electricity integration from renewable sources, frequency control, and voltage management. The first-generation Powerwall has a daily cycle capacity of 6.4 kWh. Users with higher energy demands can connect several Powerwalls to increase capacity even more.

1.3.2 Vanadium redox-flow battery The vanadium redox-flow battery is a novel energy storage device for power grid applications. As the catholyte or anolyte is cycled, charge is

16

Pumped Hydro Energy Storage for Hybrid Systems

added or withdrawn from the reactant tanks via a membrane. The battery makes use of vanadium’s capacity to thrive in four distinct oxidation states in solution so as to create a battery with only one electroactive component instead of two (Sánchez-Díez et al., 2021). The enormous capacity may be utilized to balance grid loads and store energy from intermittent sources like wind and photovoltaics. While it has technological advantages over standard rechargeable batteries, such as the possibility of separate liquid tanks and a near limitless lifetime, current implementations are far less powerful and need more complicated electronics.

1.3.3 Solid-state batteries A solid-state battery is a type of battery that employs solid electrodes as well as electrolyte rather than the liquid or polymer gel. Solid electrolytes are used in solid-state batteries, which offer better energy densities and are less prone to fire than liquid electrolytes. Solid-state batteries are suited for large-scale grid applications due to their reduced bulk and improved safety features. They offer substantial benefits over lithium-ion batteries in largescale grid storage, but are currently costly due to their less-developed condition (Sagadevan et al., 2021). The rapid growth of lithium-ion production has resulted in economies of scale that solid-state batteries may find difficult to match in the future.

1.4 Case study applications of energy storage solutions 1.4.1 Off-grid school lighting in Angola AllCell supplied a school in Angola, Africa, with lithium-nickel-cobaltaluminum batteries rated at 200 W/1300 Wh (Kempener & Borden, 2015). This was for off-grid illumination that was paired with solar photovoltaic energy. Previously, there was no lighting or power in the school. It may stay open longer and offer additional services by installing lights. Lighting four classes for up to 8 h per day is anticipated to cost USD $2 per day. The project was commissioned by a nonprofit organization that focuses on energy solutions in impoverished countries. The organization was looking into whether lithium-ion batteries were of better value compared to lead-acid batteries in off-grid applications in hot environments. According to AllCell, lithium-ion batteries are more resistant to high temperatures than lead-acid batteries, making them more suited to hot environments. In addition, AllCell has its own patented thermal management

Energy storage technologies

17

substance which helps to keep the battery from overheating, which is especially crucial in Africa due to the hot temperature.

1.4.2 Off-grid frequency response in Alaska The utility KEA received a 3 MW/750 kWh advanced lead-acid solution from Xtreme Power, which was bought by Younicos (Kempener & Borden, 2015). This intended to incorporate more wind power into an Alaskan island system. The KEA system has a peak load of roughly 27 MW and a baseload of about 11 MW; 4.5 MW of wind power capacity has already been incorporated into the system, with an additional 4.5 MW on the way. Aside from the installed wind capacity, the company also has 23 MW of hydropower and 33 MW of diesel generating. According to studies, current electricity assets will not be able to offer enough frequency response to compensate for the additional 4.5 MW of wind that will be installed. KEA used Xtreme Power’s battery technology to offer frequency response. The technology checks grid conditions 100 times per second and can supply 3 MW of electricity in 50 ms if grid frequency dips drastically. Every day, the system responds to an average of 285 of these occurrences. This allows for far better utilization of the wind resource. Although a huge quantity of electricity (up to 3 MW) may be required, these occurrences typically last only a few minutes. Depth of discharge (DoD) is projected to be less than 20% and, on average, approximately 5%, though this has not been precisely measured. The enhanced lead-acid battery system was thought to be well suited for this purpose. This is due to the fact that the system maintains a high state of charge and may discharge swiftly for extremely brief periods of time. Given that lead-acid has superior economics than lithium-ion, this kind was also seen as reasonably inexpensive. According to the firm, the most crucial functioning condition is temperature. The temperature within the container must be maintained between 20°C and 30°C.

1.4.3 Time shift and ancillary services case study in China Prudent Energy supplied China’s Wind Power Research and Testing Centre with a 500 kW/1 MWh vanadium redox-flow battery (Kempener & Borden, 2015). The study is being undertaken in collaboration with the China EPRI. It was finished in 2011 and is currently operational. The wind capacity at the Centre is 78 MW, while the solar photovoltaic capacity is 640 kW. More of this energy may now be fed into the grid thanks to the battery. It does this by storing power during periods of low

18

Pumped Hydro Energy Storage for Hybrid Systems

demand and surplus wind energy and releasing it when demand rises. In addition, the installation can provide services like as load following and voltage support in a quicker timeframe. The facility is also meant to analyze the battery’s performance so that the battery may be tested by the local utility, the State Grid Corporation of China. The electrolyte in the vanadium flow battery is contained in storage tanks. Pumps circulate the electrolyte through the system’s cell stack, forcing vanadium ions to react and generate a charge. This is then sent to a DC circuit, where the conditions for electrical discharge are created. The electrolyte may be injected back into the tanks since the process is reversible. This technology, unlike sodium-sulfur batteries, operates at ambient temperature and at low pressure.

1.5 Barriers and challenges in energy storage technologies Renewable energy generation, distributed generation, micro grid, grid integration, transmission and distribution smart grid, and other services are all potential applications for energy storage technologies. Energy storage technology development necessitates innovation in terms of capacity, life duration, and cost. Furthermore, cheap cost is necessary for high-efficiency physical storage technology. Secondly, research should not only focus on energy storage technology from a theoretical standpoint but rather demonstration projects with detailed evaluations should be developed to encourage the industrialization and commercialization of energy storage systems. Barriers to the deployment of electric energy storage include cost, market risks, modeling challenges, as well as technology and regulatory risks

1.5.1 Cost The enormous cost of research, permitting, licensing, planning, building, and operating new storage facilities is among the most significant hurdles to their growth (Baran, 2017). Although these costs are not prohibitively expensive, speculation surrounding the monetary value and cost recovery makes new storage facility investments riskier.

1.5.2 Market risk and business model While high cost remains the major impediment to increasing storage capacity in the electricity sector, the absence of cost recovery methods

Energy storage technologies

19

and a clear business model for storage is also crucial (Baran, 2017). Energy storage is experiencing a crisis of identity, as it finds its usage as a generating and load, transmission, and distribution asset. As a result, choosing the optimal storage value might be tricky. Energy storage is extremely valuable in two situations: energy markets with large price differentials between peak and off-peak times, and organized marketplaces with robust auxiliary service sectors.

1.5.3 Modeling challenges Current modeling approaches struggle to capture the benefits and uses of energy storage, and as a result, energy storage solutions are undervalued (Baran, 2017). Energy storage facilities, such as batteries, are challenging to model since they may function as both a load and a generator. They can ramp up fast, even cycling back and forth between charging and discharging several times within the hour; they have a finite amount of energy they can release over a period; and they take time to rejuvenate. Although these modeling techniques are methodical, their overall effectiveness is frequently insufficient. In analytic modeling, the bottom-up approach is used to investigate every aspect of the system and its contributions individually, then create the entire system from the single components.

1.5.4 Technology risk Energy storage development and implementation are further hampered by inherent technological risks. Despite the fact that storage technologies have been accessible for decades, current technological breakthroughs and the rising popularity of storage raise worries about the danger of producing extra storage capacity (Baran, 2017). These risks include worries about safety, the environment, the resource’s lifetime, and lifecycle as well as other factors.

1.5.5 Regulatory barriers Energy storage development and deployment cannot proceed at the rate required to optimize its utilization unless new rules are implemented, or existing policies are changed. Policy barriers might simply be a lack of policy that encourages the deployment of new technologies, such as energy storage, to solve emerging challenges such as increasing variable energy resources (Baran, 2017). Policy barriers might also include old laws

20

Pumped Hydro Energy Storage for Hybrid Systems

that do not necessarily represent the complex elements of energy storage, or onerous restrictions that are not integrated across the system (Baran, 2017).

1.6 Conclusions As electricity systems advance, there is a growing industry acknowledgment of the need to install further innovative and adaptable storage technologies. These adaptive solutions are crucial for meeting rising demand for a variety of uses, allowing for the reliable integration of intermittent renewables, and enabling cost-effective transitioning between supply and storage. Nonetheless, significant progress in building supporting policy and commercial frameworks for energy storage continues to be made across the world.

References Badwal, S. P. S., Giddey, S. S., Munnings, C., Bhatt, A. I., & Hollenkamp, A. F. (2014). Emerging electrochemical energy conversion and storage technologies. Frontiers in Chemistry, 2. Available from https://doi.org/10.3389/FCHEM.2014.00079. Baran, E. (2017). Barriers to utility scale electric energy storage. West Interstate Energy Board. Available from https://www.westernenergyboard.org/wp-content/uploads/2017/02/ 02-28-17-WIEB-Baran-Barriers-to-Electric-Energy-Storage-1.pdf Accessed 04.11.21. Brown, D. R., & Chvala, W. D. (2009). Flywheel energy storage: An alternative to batteries for ups systems. Energy Engineering: Journal of the Association of Energy Engineers, 102, 7 26. https://doi.org/10.1080/01998590509509440. Clean Technical. Tesla megapack, powerpack, & powerwall battery storage prices per kwh— Exclusive. (2020). ,https://cleantechnica.com/2020/10/05/tesla-megapack-powerpack-powerwall-battery-storage-prices/.. Department of Energy. Hydrogen storage. (n.d.). ,https://www.energy.gov/eere/fuelcells/ hydrogen-storage. Accessed 28.01.22. Donadei, S., & Schneider, G.-S. (2016). In T. M. B. T.-S. E. Letcher (Ed.), Chapter 6 Compressed air energy storage in underground formations (pp. 113 133). Oxford: Elsevier. Available from https://doi.org/10.1016/B978-0-12-803440-8.00006-3. Energy Systems & Energy Storage Lab. Supercapacitors. (n.d.). ,http://eseslab.com/ ESsensePages/Supercaps-page. Accessed 31.01.22. Giddey, S., Badwal, S. P. S., & Ju, H. K. (2018). Polymer electrolyte membrane technologies integrated with renewable energy for hydrogen production. Current Trends and Future Developments on (Bio-) Membranes: Renewable Energy Integrated with Membrane Operations. Available from https://doi.org/10.1016/B978-0-12-813545-7.00010-6. India Energy Storage Alliance (IESA). Classification of energy storage technologies: An overview. Emergging Technol News. (2020). ,https://etn.news/energy-storage/classification-ofenergy-storage-technologies-an-overview. Accessed 11.03.22. IRENA. (2018). Global energy transformation: A roadmap to 2050. International Renewable Energy Agency, Abu Dhabi. Kempener, R., & Borden, E. (2015). Battery storage for renewables: Market status and technology outlook. International Renewable Energy Agency.

Energy storage technologies

21

Krivik, P., & Baca, P. (2013). Electrochemical energy storage. In A. F. Zobaa (Ed.), Energy storage - Technol appl. IntechOpen. Available from https://doi.org/10.5772/52222. Larsen, H. H., & Sønderberg Petersen, L. (2013). DTU international energy report 2013: Energy storage options for future sustainable energy systems. Denmark. Lovegrove, K., Lavine, A., Aryafar, H., & Chen, C. (n.d.). Leveraging the ammonia industry for solar energy storage. CEP Magazine. Avaiable from https://www.aiche.org/resources/ publications/cep/2017/july/leveraging-ammonia-industry-solar-energy-storage Accessed 14.03.22. Luo, X., Wang, J., Dooner, M., & Clarke, J. (2015). Overview of current development in electrical energy storage technologies and the application potential in power system operation. Application Energy, 137, 511 536. Available from https://doi.org/10.1016/ J.APENERGY.2014.09.081. National Renewable Energy Laboratory (NREL). Pumped thermal electricity storage. (n.d.). ,https://www.nrel.gov/csp/pumped-thermal-electricity-storage.html. Accessed 12.03.22. Nguyen, T., & Savinell, R F. (2010). Flow batteries. Electrochemical Society Interface. Available from http://large.stanford.edu/courses/2011/ph240/garg1/docs/fal10_p054056.pdf Accessed 14.03. 22. Nikolaidis, P., Poullikkas, A. (2017). A comparative review of electrical energy storage systems for better sustainability. Journal of Power Technologies, 97(3), 220 245. Osman, A. I., Mehta, N., Elgarahy, A. M., Hefny, M., Al-Hinai, A., Al-Muhtaseb, A. H., et al. (2021). Hydrogen production, storage, utilisation and environmental impacts: A review. Environmental Chemistry Letters, 20, 153 188. Available from https://doi.org/ 10.1007/S10311-021-01322-8, 2021 201. Perera, F. (2018). Pollution from fossil-fuel combustion is the leading environmental threat to global pediatric health and equity: Solutions exist. International Journal of Environmental Research and Public Health, 15. Available from https://doi.org/10.3390/IJERPH15010016. Rastler, D. (2010). Energy storage technology options: A white paper primer on applications. Palo Alto: Costs, and Benefits. Roskosch, D., & Atakan, B. (2017). Pumped heat electricity storage: Potential analysis and orc requirements. Energy Procedia, 129, 1026 1033. Available from https://doi.org/ 10.1016/J.EGYPRO.2017.09.235. Sagadevan, S., Johan, M. R., Marlinda, A. R., Akbarzadeh, O., Pandian, K., Shahid, M. M., et al. (2021). Background of energy storage. Advanced Supercapacitor Supercapattery. Available from https://doi.org/10.1016/b978-0-12-819897-1.00003-3. Sánchez-Díez, E., Ventosa, E., Guarnieri, M., Trovò, A., Flox, C., Marcilla, R., et al. (2021). Redox flow batteries: Status and perspective towards sustainable stationary energy storage. Journal of Power Sources, 481, 228804. Available from https://doi.org/ 10.1016/J.JPOWSOUR.2020.228804. Sarbu, I., & Sebarchievici, C. (2018). A comprehensive review of thermal energy storage. Sustain, 10. Available from https://doi.org/10.3390/su10010191. Valera-Medina, A., Xiao, H., Owen-Jones, M., David, W. I. F., & Bowen, P. J. (2018). Ammonia for power. Progress in Energy and Combustion Science, 69, 63 102. Available from https://doi.org/10.1016/J.PECS.2018.07.001.

This page intentionally left blank

CHAPTER 2

Need for pumped hydro energy storage systems Felix A. Diawuo1,2 and Roland Teye Amanor3 1

School of Energy, UENR, Sunyani, Ghana Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana 3 Department of Chemical Engineering, Budapest University of Technology and Economics, Budapest, Hungary 2

Contents 2.1 Introduction 2.2 Benefits of pumped hydro energy storage 2.2.1 Load balancing and peak shaving 2.2.2 Grid stabilization- voltage and frequency regulation 2.2.3 Fast and flexible ramping 2.2.4 Black start 2.3 Hybrid pumped hydro energy storage designs and applications 2.3.1 Off-grid/standalone applications 2.3.2 Grid application 2.4 Climate change impact on pumped hydro energy storage and its infrastructure 2.4.1 Climate adaptation and mitigation options 2.5 Conclusions References

23 27 27 29 31 31 32 32 35 37 38 38 39

2.1 Introduction Fossil fuel is the go-to source of fuel for electricity generation for most residential, commercial, and industrial applications. As efficient as it may be in generating electricity, there remain concerns over the finite nature of the resource for sustainability, energy security, and most importantly the environmental impact. Fossil fuels are the major contributors to greenhouse gas (GHG) emissions and raising concerns about the climate. To address these major concerns, it is imperative to invest in renewable energy sources (RES). Integration of RES is a growing phenomenon to limit dependence on fossil fuels. However, there are problems with the intermittent nature (Ricardo, Vilanova, Thiessen, José, & Perrella, 2020; Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00001-7

© 2023 Elsevier Inc. All rights reserved.

23

24

Pumped Hydro Energy Storage for Hybrid Systems

Xu et al., 2019) of the resource as well as the dependence of the generative properties on spatial distribution as outlined by Kocaman and Modi (2017). Energy storage technologies provide an enormous potential to provide support for renewable energy systems for grid integration. This is achieved by storing and discharging energy when needed hence providing ancillary services that help maintain grid stability and security. Furthermore, Barbour, Wilson, Radcliffe, Ding, and Li (2016) discussed various importance of bulk electrical energy storage (EES) systems of which some include: • facilitating increased deployment of low-carbon generation • increasing reliability for end-users • facilitating time of use energy management • increasing system flexibility • reducing the volatility of electricity prices • reducing the need for transmission upgrades/new transmission infrastructure • reducing overall pollutant emissions. Pumped hydro energy storage (PHES) as part of the energy storage technologies is the most matured and heavily utilized for high power applications (Díaz-gonzález, Sumper, & Gomis-Bellmunt, 2016). Globally, PHES gives the largest amount of energy storage capacity and it is considered to have a weight share of 95% 99% of the total energy storage systems with an aggregated installed capacity of over 170 GW (Alhadhrami & Alam, 2015; Al Zohbi, Hendrick, Renier, & Bouillard, 2016; Benato & Stoppato, 2018; Chaudhary & Rizwan, 2018; Melikoglu, 2017; Ricardo et al., 2020). In historical context, the very first PHES system which was constructed in the world around the 1890s was located in the alpine regions of Austria, Switzerland, and Italy. The construction design had the motor-driven pump and the generator-turbine mounted separately on two shafts. This type of design was practically shelved and seldom used due to its high capital investment requirements (Komarnicki, Styczynski, & Lombardi, 2017). By the middle of the 20th century, the single reversible pump-turbine became the technology of choice and has since been dominant for PHES design. The evolution of PHES development was quite slow until the 1960s when many electric utilities across different countries visualized and started more investments in nuclear power. The PHES system then became a complementary technology to nuclear power in delivering peak load power.

Need for pumped hydro energy storage systems

25

There are currently over 340 PHES projects distributed around the globe in over 14 countries with China, United States (US) and Japan having the largest capacities. China is presently leading with over 31 GW followed by the US and then Japan as shown in Fig. 2.1. But with the US having other PHES systems contracted and announced as shown in Fig. 2.2, it is likely to surpass that of China in the near future if those projects eventually come on stream (Vasudevan, Ramachandaramurthy, Venugopal, Ekanayake, & Tiong, 2021). The second biggest gridconnected PHES in the world, popularly called the world
s largest battery is in the US located in Bath County, Virginia and it has a 3-GW generation capacity. China has recently started operating its newly constructed 3.6 GW PHES plant called Fengning which is located in the Hebei Province is now the world’s biggest pumped storage facility (Letcher, 2018). Within these countries with high PHES capacity, the main reason for the use of PHES beside the orographic rationale is the decoupling of generated power by nuclear plants from loads (Komarnicki et al., 2017). Within the European Union (EU) enclave, there is a projected new PHES installation of over 7.4 GW which is equivalent to about 20% increase in its installed capacity (Díaz-gonzález et al., 2016). It is also worth noting from Fig. 2.1 that except for South Africa and Morocco,

Figure 2.1 Global distribution of pumped hydro energy storage PHES with capacities (Vasudevan et al., 2021). PHES, Pumped hydro energy storage.

26

Pumped Hydro Energy Storage for Hybrid Systems

Figure 2.2 New PHES units announced and contracted by different countries (Vasudevan et al., 2021). PHES, Pumped hydro energy storage.

the rest of the African continent has neither announced nor contracted pumped hydro systems. Renewable energy systems on the African continent are constantly increasing and with these renewable sources being intermittent, pumped hydro storage systems can be developed to help stabilize generation and shave off peaks from the demand curve. The critical policy drivers for the development of PHES are based on the type of regulations and financial regimes instituted, which are mostly influenced by national policies. Prior to China becoming the lead in PHES, Japan was leading. This was because, over the years, the Japanese electricity sector operated a vertically integrated market structure, where utilities build, own, and operate PHES. This provided a stable and formularized business atmosphere that was favorable to PHES investments. Japan is the leader in employing seawater PHES and variable PHES. The 30-MW seawater PHES is first constructed in the world and has been in operation since 1999 (Komarnicki et al., 2017; Yang, 2018). China, a blow-in in global PHES deployment though with first PHES construction in 1968, has undergone several meandering regulatory policies spanning over the last two decades. Initially, the construction of PHES was done by both the local government authorities and the local grid utilities but the two bodies had completely different pricing models, which later became counter-productive (Yang, 2018). In the year 2014, a new regulation was promulgated which gave sole proprietorship to the grid companies to construct and manage PHES, as PHES stations were considered as part of transmission facilities. The construction and operation costs were

Need for pumped hydro energy storage systems

27

then incorporated as part of the operation costs of the grid companies (Yang, 2018). This regulation became the impetus for the fast expansion and development in the deployment of PHES in China.

2.2 Benefits of pumped hydro energy storage Pumped hydro energy storage is beneficial to the energy sector in many ways. This technology generates clean energy and contributes little or nothing to carbon footprint. The PHES technology has enormous opportunities in contributing to achieving, in particular, the sustainable development goal 7 (SDG 7) target. Its coupling with other renewable sources provides stability on the transmission network in the power system. Some of the benefits in relation to load balancing, peak shaving, fast and flexible ramping, black start, and grid stability are discussed next.

2.2.1 Load balancing and peak shaving Usually, in power generation systems, baseload technologies such as nuclear or coal power plants operate economically if their generation output is fixed at its optimum value. Any attempt to alter their output to equate or balance the load tends to make their operation inefficient. To address this issue, PHES can be used to requite their inflexibility. PHES, therefore, provides load-levelling or load shifting services for the utilities and it does so by consuming energy during low-price (off-peak) periods and generating at high-price (peak demand) periods. This means that excess nighttime generation is used to pump water into the upper reservoir so that it could be released for generation in the daytime. This decreases the overall cost of production of the system by avoiding costly peak generation during peak demand periods and increasing the use of cheap baseload generation during off-peak periods (Torrealba, 2016). In similar settings for intermittent technologies, during the day solargenerated electricity can be used for charging the PHES which can then deliver electricity during the evening or cloudy periods. In so doing, any unexpected outage or curtailment is assuaged through the storage of electricity surplus, which is then used during high demand periods. Fig. 2.3, for example, shows the supply and demand balance based on the complementary activity of solar and PHES at the Kyushu plant in Japan. The 8.07 GW solar photovoltaic (PV) plant, on May 3, 2018, reached an output of 6.21 GW which represented 81% of the day’s peak demand at around noontime (IRENA, 2020). The excess electricity generated was

28

Pumped Hydro Energy Storage for Hybrid Systems

Figure 2.3 Load balancing at Kyushu plant, Japan (IRENA, 2020).

used to pump water to the upper reservoir, and the thermal generation was reduced to accommodate the huge amount of energy from the solar plant. In this instance, the PHES prevented a shutdown of the thermal stations by utilizing the surplus energy from the solar plant. The PHES was used to meet peak demands during lower output from the solar plant. In a similar case as shown in Fig. 2.4, the demand and wind generation together with PHES activity for a day at the La Muela PHES facility in Spain is presented. When wind generation is relatively higher and demand is lower, the PHES pumps water into the higher reservoir and then delivers power in the evening when demand is higher and wind generation is lower. This complementarity improves flexibility while the efficiency of the overall system is positively impacted. Some case-based benefits of PHES related to load balancing and peak shaving have been discussed in other related studies. Torrealba (2016), for example, emphasized that for peaks and troughs of net-demand which mostly last for a few hours or even a very long time, PHES is able to smoothen these peaks and troughs. This then leads to a substantial reduction of stress on thermal generation, the numbers of starts and stops, and the quantity of renewable energy lost during production. At this stage, thermal generation is able to run close to maximum efficiency, thereby saving cost and reducing emissions. Notton, Mistrushi, Stoyanov, and Berberi (2017) further confirmed that PHES systems are the best option for smoothing electric power production at the cheapest cost and prevent imbalances caused by wind energy, thus reducing prediction inaccuracies. A model was developed for

Need for pumped hydro energy storage systems

29

Figure 2.4 Wind and PHES complementarity for load balancing at La Muela PHES facility, Spain (IRENA, 2020). PHES, Pumped hydro energy storage.

solar PV, wind energy, and pumped hydro storage hybrid system with the objective of verifying whether the system could shave peak demand to replace costly and polluting thermal plants. The simulation results indicated that the hybrid system could cover up to 80% of the peak demand on an annual basis, thereby jettisoning the use of fossil-based combustion turbines.

2.2.2 Grid stabilization- voltage and frequency regulation In the grid network, frequency stability occurs when the power system is able to retain steady frequency after system interruption or disruption, which eventually leads to an imbalance between generation supply and demand load (Yang, 2019). So typically, when demand increases above generation supply, frequency declines. The reverse happens when supply

30

Pumped Hydro Energy Storage for Hybrid Systems

Figure 2.5 System load following and frequency regulation. Frequency regulation is the fast fluctuating component that balances total load, while load following is the slower trend (Denholm et al., 2010).

is higher than demand. Fig. 2.5 highlights a situation where a quick response for frequency regulation is needed (in red color) in addition to ramping requirements in a longer term (in blue color). In this instance, the morning load rises smoothly by close to 400 MW in 2 h. At this same period, rapid short-term ramps of 6 50 MW is noticed within a few minutes. Due to these fast fluctuations, spinning reserve power plants, which are online and “spinning”, are usually required to respond quickly to regulate the frequency (Denholm, Ela, Kirby, & Milligan, 2010). On the other hand, voltage stability occurs when the power system is able to maintain a steady voltage at the various busbars after an interruption disrupts an initial operating condition. This is restored when equilibrium is established between supply and demand (Yang, 2019). PHES can provide voltage control by using the power electronics of variable-speed PHES plants that can mimic the voltage control capability of conventional generators or through the use of conventional generators in fixed-speed and ternary PHES units (Hino & Lejeune, 2012; Torrealba, 2016). As discussed previously, voltage regulation and reactive power control can be carried out using the generator’s excitation system. The automatic voltage regulator which is fitted with Proportional Integral Derivative control

Need for pumped hydro energy storage systems

31

loops is used in controlling the voltage which then assists the automatic synchronizer, thus providing the desired voltage for synchronization (Ramos, 2000).

2.2.3 Fast and flexible ramping The variable speed turbines of the PHES provide flexible ramping capacities, which allows it to increase or decrease its generating output depending on forecasted load variations. The rapid ramping response of PHES can counteract the resource fluctuations associated with variable renewable energy (VRE) sources. It can attain full capacity within less than 30 s when connected to the grid network. An example is the 1.8 GW Dinorwig PHES in Wales which can attain full load capacity within 16 s. This makes PHES suitable for assisting the penetration of VREs, while maintaining the stability and reliability of the system. PHES is being used to balance the so-called duck curve, where the difference between demanded electricity and solar energy production around sunset reaches a maximum (IRENA, 2020). The 1.8 GW Fengning 2 PHES in China is able to balance generation capacities from solar and wind to supply Beijing-Tianjin-North Hebei grid (IRENA, 2020).

2.2.4 Black start Black start refers to a unit that has the capability to start its own power without the support of the grid in a situation where is there is a major system collapse or system-wide blackout. Black start services can be provided by PHES as far as the reservoir has enough stored water to power the turbines without any unique arrangement for black start operation. Only small power is needed at the station since there is no requirement for cooling or fuel preparation. Some capacities of PHES are large enough to adequately supply power to excite the transmission system, pick up loads, and supply station power to start up other power plants. PHES is quite suitable for black start only when water is available or held in reserve for it. This is because economical dispatch may empty the upper reservoir tank (IRENA, 2020). An example is the case of the 400 MW Cruachan PHES plant in Scotland which can attain full load within 30 s and maintain generation for 16 h if needed, thus guaranteeing power stability for system operation. Aside the balancing services, the plant provides black start capability to the National Grid (IRENA, 2020).

32

Pumped Hydro Energy Storage for Hybrid Systems

2.3 Hybrid pumped hydro energy storage designs and applications RE sources such as solar and wind are intermittent in nature and do not produce continuous energy regularly. So, to connect them to a commercial grid-scale system makes it unstable, and hence an energy storage system is required. Of the renewable sources, wind is the most unstable because it is a highly fluctuating meteorological parameter. While wind energy sources cannot provide energy on demand independently, they can be used together to form a pumped storage system and meet demands collectively. PHES systems are currently being coupled with other forms of energy and numerous studies yield promising results for these novel integrated systems. Hybrid PHES designs for both grid and off-grid applications are discussed next.

2.3.1 Off-grid/standalone applications In the off-grid applications, three different proposed hybrid schemes are highlighted and discussed. 2.3.1.1 Wind-pumped hydro energy storage hybrid system Pali and Vadhera (2018) proposed a novel concept of small isolated electric power generation for remote and rural areas where open wells are available. In this proposed integrated system, wind is used as the primary source of energy combined with PHES. The upper reservoir of the pumped hydro system required is made on the ground and an appropriate well is used as the lower reservoir as shown in Fig. 2.6. The components of the system are composed of the wind turbine, upper reservoir, open well, water valves, penstock, pico-hydro turbine, hydraulic pump, and electric generator. Here, unlike other PHES designs, the wind turbine is used to drive the hydraulic pump but not the electric generator. In this architecture, both the discharge of water from the upper reservoir for electricity generation is done simultaneously and continuously with the charging of water into the upper reservoir from the open well by the wind turbine. The system has the advantage of not requiring any converter/inverter, batteries, transformer, and control circuits. The use of the wind unlike solar is present in the night, thereby helping store water continuously for day and night. Due to less design complications, the attractive features of this wind-PHES system include low cost, system

Need for pumped hydro energy storage systems

33

Figure 2.6 A novel design of an off-grid wind-PHES system (Pali & Vadhera, 2018). PHES, Pumped hydro energy storage.

reliability, and continuity in power supply at constant voltage regardless of wind speed variations. 2.3.1.2 Hybrid wind-solar-pumped hydro energy storage-battery system Shahzad, Zhong, Ma, Song, and Ahmed (2020) addressed the issue of variability and intermittency using RES for off-grid applications by proposing a hybrid pumped hydro and battery storage system as shown in Fig. 2.7 for better reliability and sustainability. The system component is composed of solar PV, wind turbine, upper and lower reservoirs, reversible adjustable pump-turbine machine, hybrid charge controller, inverter, batteries, and dump load. The proposed model uses the battery storage for low-energy shortfalls and the pumped hydro storage is used as the main storage for high-energy demand, while the wind and solar are the only sources for energy generation This means that the PHES only comes into operation to

34

Pumped Hydro Energy Storage for Hybrid Systems

Figure 2.7 Hybrid off-grid wind-solar-PHES-battery system (Shahzad et al., 2020). PHES, Pumped hydro energy storage.

shave peak power when there is a higher deficiency in the absolute power. Since the batteries have a much higher response time, it is designed to respond to any inferior power deficit. This helps avoid the PHES running at low efficiency at partial loads. This arrangement reduces the number of starts and stops of the reversible pump-turbine machine, thus improving its service life. The dump load could be, for example, a desalination plant that can be deployed with the PHES using the surplus electricity from the wind and solar sources to provide fresh water for the rural community. 2.3.1.3 Hybrid solar-wind-pumped hydro energy storage-diesel generator system Kusakana (2016) examined optimal scheduling for a distributed hybrid system with pumped hydro storage using an energy dispatch model, taking into consideration the intermittent nature of wind and solar resources. The hybrid system consisted of a solar PV, a wind turbine unit, a PHES, and a diesel generator as shown in Fig. 2.8. The energy demand required for this system is principally supplied by the solar and

Need for pumped hydro energy storage systems

35

Figure 2.8 Proposed hybrid solar-wind-PHES-diesel generator system layout and power flow (Kusakana, 2016). PHES, Pumped hydro energy storage.

wind units. When there is excess supply from these two renewable energy technologies, the surplus is used in pumping water to the upper reservoir of the PHES system. During periods of shortage supply from the solar and wind units, the stored water in the upper reservoir is discharged to drive the turbine-generator set to meet the demand shortfalls. The diesel generator is only used when the solar and wind units and the PHES are not able to respond to the demand requirements. For isolated power generation, this system arrangement can be viewed as an attractive and interesting alternative coupled with benefits such as lowered energy production cost, increased availability and reliability of electrical power supply, and lower impacts on the environment. The findings from simulation results showed that the use of PHES makes it possible to deal with any load operational constraints that normally need rapid response from the power generation.

2.3.2 Grid application In the grid application, two different proposed hybrid schemes are highlighted and discussed next.

36

Pumped Hydro Energy Storage for Hybrid Systems

2.3.2.1 Integrated fossil fuel-wind-pumped hydro energy storage system for energy supply and desalination Segurado, Madeira, Costa, Dui´c, and Carvalho (2016) proposed an integrated wind power desalination and PHES for S. Vicente Island in Cape Verde and developed a model for its optimization. In the proposed integrated system as shown in Fig. 2.9, fossil fuel and wind power are used to supply power to the grid and for the desalination plant to supply fresh water. During excess production of energy from the wind unit, the surplus is used to pump water from the lower reservoir to the upper reservoir for energy storage. During load balance situations, the PHES is used to supply power to the grid. This system has the benefit to deal with water scarcity issues, reduce power and water supply costs, and reduce the dependence on expensive fossil fuel and a significant reduction in carbon dioxide (CO2) emissions. 2.3.2.2 Double storage pumped hydro energy storage-battery powered by renewable energy sources Abdelshafy, Jurasz, Hassan, and Mohamed (2020) developed an energy management system for grid-connected double energy storage system composed of PHES and battery banks as shown in Fig. 2.10. In this architecture, the demand load is mainly supplied by RES (wind and solar) while the excess power generated is controlled by the energy management system to pump water from the lower to the upper reservoir and also charge the batteries while the remaining is fed into the electric grid. In a situation of supply deficit from RES, the PHES and/or batteries are used while the residual deficient energy is supplied by the electric grid. In

Figure 2.9 Fossil fuel-, wind-, and pumped hydro PHES integrated energy system (Segurado et al., 2016). PHES, Pumped hydro energy storage.

Need for pumped hydro energy storage systems

37

Figure 2.10 PHES-battery storage systems powered by renewable energy sources and grid connected (Abdelshafy et al., 2020). PHES, Pumped hydro energy storage.

this arrangement, the RES, PHES, and battery banks are localized in the load center in close proximity to minimize transmission losses. This system has the advantage of reducing electricity cost and minimizing energy exchanges with the grid.

2.4 Climate change impact on pumped hydro energy storage and its infrastructure Climate change has the potential to impact hydropower development through changes in rainfall, water availability, and significant variation in temperature regimes. Warmer temperatures enhance evaporation from the earth surface, making periods of low precipitation dryer than it would have been in cooler condition. This worsens drought conditions. Most early-stage technical assessments rely on historical hydrometeorological records. The long lifespan of hydropower infrastructure exposes their operationalization to severe impact of climatic and hydrological variability driven by the climate change. The climate-induced changes in river hydrology have direct impact on the various hydropower technologies, including the run-off-the-river, storage, and pumped storage plants. For instance, while development of hydropower is seen as an effective GHG mitigation strategy, smaller-scale hydropower is particularly vulnerable to

38

Pumped Hydro Energy Storage for Hybrid Systems

climate change given its dependence on water for power generation. Electricity generation of run-of-river plants is more sensitive to changes in low flows (particularly minimum flows) than storage plants because it does not have significant storage to buffer changes in flow. Though impacts to conventional storage and PHES are similar, PHES is generally less vulnerable, given its effective capture and re-use of stored water, offering additional operational flexibility. But in a long-term, large-scale reduction of stored water under drought condition for pumped hydro storage can induce significant reduction in its electricity generation.

2.4.1 Climate adaptation and mitigation options Pumped hydro energy storage should be planned and designed to absorb stress imposed by climatic and hydrological variability resulting from climate change and climate-induced disasters. Risks of climate change to PHES should be addressed by integrating climate resilience into shortand long-term hydropower development—and broader energy system— project planning, development, and Operation and Maintenance (O&M). Such planning should consider both climate risks and GHG reduction opportunities across the energy supply and demand chains, and the interrelationships and dependencies between variable renewable resources. Design should have contingencies that promote constructive, minimally destruct failure and efficient, rapid adaption to less vulnerable future state. In the planning and design stage of hydropower infrastructure, the following guidelines should be considered: project climate risk screening, initial analysis, climate stress test, climate risk management, and project monitoring reporting and evaluation (IHA, 2020). Careful implementation of the PHES projects can mitigate climate change impacts if the International Hydropower Association (IHA) hydropower sustainability assessment protocol is integrated in the entire project phases (IHA, 2018). Additionally, PHES can be integrated with the installation of floating photovoltaics (FPV) in existing PHES reservoirs. The FPV can significantly support reduction in the evapotranspiration of the reservoir, thus limiting the climate change impact.

2.5 Conclusions As the world moves with far greater capacity of renewable energy integration, the reality of affordable, reliable, secured, and sizeable scale of energy storage should be on the table. Luckily, a technology has been in

Need for pumped hydro energy storage systems

39

existence for long in delivering grid-scale energy storage at relatively lower prices: the pumped hydro energy system. Indeed, for the near future, PHES stands tall as a proven commercially available technology. This chapter provided an overview of the PHES technology, its benefits in relation to load balancing, flexible ramping, black start, and grid stability. PHES provides a unique opportunity in hybridizing with other technologies to provide tailored solutions for both grid and off-grid applications. The findings from different PHES hybrid designs show a reduction in the dependence on expensive fossil fuel, significant reduction in carbon dioxide (CO2) emissions, advantage of reducing electricity cost and minimizing energy exchanges with the grid, system reliability, and continuity in the power supply.

References Abdelshafy, A. M., Jurasz, J., Hassan, H., & Mohamed, A. M. (2020). Optimized energy management strategy for grid connected double storage (pumped storage-battery) system powered by renewable energy resources. Energy, 192, 116615. Available from https://doi.org/10.1016/j.energy.2019.116615. Al Zohbi, G., Hendrick, P., Renier, C., & Bouillard, P. (2016). The contribution of wind-hydro pumped storage systems in meeting Lebanon’s electricity demand. International Journal of Hydrogen Energy, 41(17), 6996 7004. Available from https:// doi.org/10.1016/j.ijhydene.2016.01.028. Al-hadhrami, L. M., & Alam, M. (2015). Pumped hydro energy storage system : A technological review, 44, 586 598. Available from https://doi.org/10.1016/j.rser.2014.12.040. Barbour, E., Wilson, I. A. G., Radcliffe, J., Ding, Y., & Li, Y. (2016). A review of pumped hydro energy storage development in significant international electricity markets. Renewable and Sustainable Energy Reviews, 61, 421 432. Available from https:// doi.org/10.1016/j.rser.2016.04.019. Benato, A., & Stoppato, A. (2018). Pumped thermal electricity storage: A technology overview. Thermal Science and Engineering Progress, 6, 301 315. Available from https:// doi.org/10.1016/j.tsep.2018.01.017. Chaudhary, P., & Rizwan, M. (2018). Energy management supporting high penetration of solar photovoltaic generation for smart grid using solar forecasts and pumped hydro storage system. Renewable Energy, 118, 928 946. Available from https://doi.org/ 10.1016/j.renene.2017.10.113. Denholm, P., Ela, E., Kirby, B., & Milligan, M. (2010). The role of energy storage with renewable electricity generation. Available from https://www.nrel.gov/docs/fy10osti/47187.pdf. Díaz-gonzález, F., Sumper, A., & Gomis-Bellmunt, O. (2016). Energy storage in power systems. John Wiley & Sons Ltd. Hino, T., & Lejeune, A. (2012). Pumped storage hydropower developments. Comprehensive Renewable Energy, 6. Available from https://doi.org/10.1016/B978-0-08-0878720.00616-8. IHA. (2018). Hydropower sustainability assessment protocol. Published by International Hydropower Association 2020. Available from https://assets-global.website-files.com/ 5f749e4b9399c80b5e421384/5fa7e0f0d7fd2619e365e8e5_hydropower_sustainability_ assessment_protocol_07-05-20.pdf.

40

Pumped Hydro Energy Storage for Hybrid Systems

IHA. (2020). Hydropower status report 2020. International Hydropower Association, 1 83. IRENA. Innovative operation of pumped hydropower storage. (2020). ,https://www.irena.org/-/ media/Files/IRENA/Agency/Publication/2020/Jul/IRENA_Innovative_PHS_operation_ 2020.pdf?la 5 en&hash 5 4533ABDD9EA1D0755720FF46F3241FAB56C65014.. Kocaman, A. S., & Modi, V. (2017). Value of pumped hydro storage in a hybrid energy generation and allocation system. Applied Energy, 205(June), 1202 1215. Available from https://doi.org/10.1016/j.apenergy.2017.08.129. Komarnicki, P., Styczynski, Z., & Lombardi, P. (2017). Electric energy storage systemsFlexibility options for smart grids. Springer-Verlag GmbH Germany. Kusakana, K. (2016). Optimal scheduling for distributed hybrid system with pumped hydro storage. Energy Conversion and Management, 111, 253 260. Available from https://doi.org/10.1016/j.enconman.2015.12.081. Letcher, T. M. (2018). Storing electrical energy. Managing Global Warming: An Interface of Technology and Human Issues, 365 377. Available from https://doi.org/10.1016/B9780-12-814104-5.00011-9. Melikoglu, M. (2017). Pumped hydroelectric energy storage: Analysing global development and assessing potential applications in Turkey based on Vision 2023 hydroelectricity wind and solar energy targets. Renewable and Sustainable Energy Reviews, 72 (January), 146 153. Available from https://doi.org/10.1016/j.rser.2017.01.060. Notton, G., Mistrushi, D., Stoyanov, L., & Berberi, P. (2017). Operation of a photovoltaic-wind plant with a hydro pumping-storage for electricity peak-shaving in an island context. Solar Energy, 157, 20 34. Available from https://doi.org/10.1016/j. solener.2017.08.016. Pali, B. S., & Vadhera, S. (2018). A novel pumped hydro-energy storage scheme with wind energy for power generation at constant voltage in rural areas. Renewable Energy, 127, 802 810. Available from https://doi.org/10.1016/j.renene.2018.05.028. Ramos, H. (2000). Guidelines for design of small hydropower plants. WREAN (Western Regional Energy Agency & Network) and DED (Department of Economic Development), Belfast. Ricardo, M., Vilanova, N., Thiessen, A., José, F., & Perrella, A. (2020). Pumped hydro storage plants: A review. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 0. Available from https://doi.org/10.1007/s40430-020-02505-0. Segurado, R., Madeira, J. F. A., Costa, M., Dui´c, N., & Carvalho, M. G. (2016). Optimization of a wind powered desalination and pumped hydro storage system. Applied Energy, 177, 487 499. Available from https://doi.org/10.1016/j.apenergy. 2016.05.125. Shahzad, M., Zhong, D., Ma, T., Song, A., & Ahmed, S. (2020). Hybrid pumped hydro and battery storage for renewable energy based power supply system. Applied Energy, 257(October 2019), 114026. Available from https://doi.org/10.1016/j. apenergy.2019.114026. Torrealba, P. J. R. (2016). The benefits of pumped storage hydro to the UK. Available from https://doi.org/10.13140/RG.2.2.18778.13768/1. Vasudevan, K. R., Ramachandaramurthy, V. K., Venugopal, G., Ekanayake, B., & Tiong, S. K. (2021). Variable speed pumped hydro storage: A review of converters, controls and energy management strategies. Renewable and Sustainable Energy Reviews, 135 (January 2020), 110156. Available from https://doi.org/10.1016/j.rser.2020.110156. Xu, B., Chen, D., Venkateshkumar, M., Xiao, Y., Yue, Y., & Xing, Y. (2019). Modeling a pumped storage hydropower integrated to a hybrid power system with solar-wind power and its stability analysis. Applied Energy, 248(March), 446 462. Available from https://doi.org/10.1016/j.apenergy.2019.04.125.

Need for pumped hydro energy storage systems

41

Yang, C. (2018). Pumped hydroelectric storage. Storing Energy. Available from https://doi. org/10.1016/B978-0-12-803440-8/00002-6. Yang, W. (2019). Hydropower plants and power systems-dynamic processes and control for stable and efficient operation. Spirnger.

This page intentionally left blank

CHAPTER 3

Characteristic features of pumped hydro energy storage systems Felix A. Diawuo1,2, Eric O. Antwi2,3 and Roland Teye Amanor4 1

School of Energy, UENR, Sunyani, Ghana Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana 3 UENR, Sunyani, Ghana 4 Department of Chemical Engineering, Budapest University of Technology and Economics, Budapest, Hungary 2

Contents 3.1 Introduction 3.2 Description of pumped hydro energy storage systems 3.2.1 Classification of pumped hydro energy storage 3.3 Pumped hydro energy storage characteristics and configuration schemes 3.3.1 Pumped hydro energy storage designs and configuration schemes 3.3.2 Advantages and disadvantages of pumped hydro energy storage 3.4 Conclusions References Further reading

43 44 45 50 53 55 57 57 58

3.1 Introduction Building a sustainable future requires effective management of our scarce natural resources. Modern approaches to resource management and the United Nations Sustainable Development Goals have been advocating for an optimization of the nexus between energy, water, and land to minimize environmental impact while reducing cost for the benefit of mankind and society (Hunt et al., 2020). Water resources are critical for society’s development, especially their application in the industry, hydropower generation, irrigation, recreation, transportation, etc. Competing interest for water use in different sectors in dry regions can pose a daunting challenge for water management. Storage reservoirs help manage

Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00006-6

© 2023 Elsevier Inc. All rights reserved.

43

44

Pumped Hydro Energy Storage for Hybrid Systems

water resources within the basins and across time periods. However, storage reservoirs demand the right geological formation which permits the reservoir level to greatly alter to allow significant amount of water to be stored (Hunt et al., 2020). Usually, storage reservoirs can require large land area, high investment cost, and evaporation to store some water and energy in plain regions. Balancing energy demand with supply can pose some challenges to network stability, especially with the penetration of variable renewable energy (VRE) sources such as solar and wind. This has necessitated the increasing demand for flexible solutions such as energy storage systems. These intermittent energy sources present hourly, daily and seasonal uncertainities and variations which require balancing and back-up systems to ensure supply reliability and network stability (Hunt et al., 2020). Batteries, which are short-term energy storage technologies, are being deployed to address the intermittent challenges. However, longterm energy storage technologies such as hydrogen, which could be used to resolve seasonal variations in the generation of electricity, are not presently economically competitive (IRENA, 2020). For proper optimization of the management of water, energy, and land resources in both short and long term, pumped hydro energy storage (PHES) systems could be the go-to solution. PHES stores energy by pumping water to the upper reservoir tank from the lower reservoir tank during period of low electricity demand (Hino & Lejeune, 2012). The water at the upper reservoir is then discharged to deliver energy to meet demand especially during peak periods when demand is high. PHES has an almost immediate start-up time to quickly respond to varying energy demand (IRENA, 2020). Due to its advanced technology using the power electronics of its generator’s variable-speed, PHES can provide voltage and frequency control which can support the integration of VRE without compromising the reliability and stability of the network system. This chapter presents the characterization of PHES, its design configurations, advantages, and disadvantages.

3.2 Description of pumped hydro energy storage systems PHES system is an energy generation system that relies on gravitational potential. PHES systems are designed as a two-level hierarchical reservoir system joined by a pump and generator, usually situated between the reservoirs (Kocaman & Modi, 2017). As shown in Fig. 3.1, during the period of energy storage, the water in the lower reservoir is pumped up to a higher elevation into the upper reservoir using low-cost electricity

Characteristic features of pumped hydro energy storage systems

45

Figure 3.1 Sketch of a typical PHES system. PHES, Pumped hydro energy storage system.

(power produced in off-peak times) and released down the pipe through the turbine to generate energy when required, usually during peak demand (Al Zohbi, Hendrick, Renier, & Bouillard, 2016; Hino & Lejeune, 2012; Rahman, Baseer, & Rehman, 2015; Yang, 2018). The inlet water flow to the turbine can be varied using gates to give a variable energy output. Variable speed pumps can be used as well to control water flow during charging (Rosen, 2020). Specific conditions such as a suitable geographical location with the appropriate elevation or head and availability of water are key to having a good PHES system. Since there is the requirement of some natural streamflow to the upper reservoir in some cases, PHES can work as a combination of pumped storage and conventional hydropower (Kocaman & Modi, 2017).

3.2.1 Classification of pumped hydro energy storage The PHES system can be grouped into several topologies with each classification having constructional or operational differences, as shown in Fig. 3.2. 3.2.1.1 Penstock The penstock serves as the sluice for directing or controlling the flow of water and it is designed to withstand maximum internal pressure during normal or abnormal operating conditions primarily due to water hammer phenomenon. The various materials used for the penstock design include steel and cast iron, reinforced concrete, pre-stressed concrete, plastic and glassfibre-reinforced plastic, etc. There are two penstock design and construction schemes, namely single and double. The single has only one

46

Pumped Hydro Energy Storage for Hybrid Systems

Pumped Hydro Storage

RESERVOIR CONFIGURATION

PENSTOCK

SINGLE

DOUBLE

CONVENTIONAL

OPEN WELL

OPERATION

NONCONVENTIONAL

ABANDONED MINES

CANALS AND STREAMS

VARIABLE SPEED

FIXED SPEED

SEA WATER PHS

Figure 3.2 Different classifications of PHES systems (Vasudevan, Ramachandaramurthy, Venugopal, Ekanayake, & Tiong, 2021). PHES, Pumped hydro energy storage system.

circuit for both pumping and turbining, while the double offers a separate and independent parallel circuit for pumping and turbining. The single type is comparatively much cheaper, while the double has the advantage of providing much more operational flexibility, which eventually delivers a quicker operation response whenever the turbine is needed. 3.2.1.2 Reservoir The reservoir serves as a storage of the available potential energy and provides a condition for diverting water through the intake. PHES system, with the upper reservoir physically isolated from a watercourse that only receives water from pumping, is classified as close loop PHES system, whereas those connected to a river that receives inflows from the water body are known as open loop PHES system. The upper and the lower reservoirs are normally installed in cascade of each other (Ardizzon, Cavazzini, & Pavesi, 2014; Kocaman & Modi, 2017; Ricardo, Vilanova, Thiessen, José, & Perrella, 2020). Site selection and water availability are key factors for consideration before the installation of these systems to obtain better efficiency. The conventional reservoir schemes are faced with challenges in relation to securing suitable sites—usually with large land size, high investment cost, long construction duration, and environmental issues.

Characteristic features of pumped hydro energy storage systems

47

However, several research activities have led to the development of nonconventional reservoir schemes, which have the ability to minimize environmental concerns of PHES. These include the seawater PHES, subsurface PHES, compressed air PHES, etc. For example, in the subsurface scheme, an attempt is made to position either upper or lower reservoir, or both reservoirs below the ground or subsurface. Due to underground excavation and construction costs, developers make use of existing subsurface systems for this scheme. An example is the 50 250 MW Elmhurst Quarry PHES project to be developed by DuPage County in Illinois, USA, which is tabled to use quarry and abandoned mine for both reservoirs (Akinyele & Rayudu, 2014). The seawater PHES uses the ocean as its lower reservoir. The 30 MW Okinawa Yanbaru PHES in Japan is one such example (Akinyele & Rayudu, 2014; Yang, 2018). Others are presently in proposal stage including the 480 MW seawater PHES in Glinsk, Ireland and the 300 MW one in Lanai, Hawaii (Akinyele & Rayudu, 2014). The compressed air PHES is a promising design which replaces the upper tank reservoir in PHES with a pressurized water container. The air within the container becomes pressurized when water is pumped into it. Therefore, instead of the potential energy being stored in the elevated water, the energy is rather stored in the compressed air. This design concept has the potential to free PHES from geographical requirements, thus making it conceivable in many locations with flexibility and scalable capacity (Yang, 2018). 3.2.1.3 Type of machine for operation The PHES has a powerhouse that contains turbines, generators, and motor pumps. The plant can have turbine generators and motor pumps, dedicated to power generation and pumping phases respectively or it can also have the same hydraulic component operating as a turbine or a pump, in which case it is classified as a reversible PHES plant as shown in Fig. 3.3 (Ricardo et al., 2020). The changeover mode between the turbine and the pump in the reversible PHES is achieved using the pony motor which speeds off the train from standstill to the synchronous rotational speed. In other situations, the start-up could be done in the pump mode whereby a static frequency converter is fed to the synchronous machine with variable frequency (Rufer, 2018). Conventionally, the reversible PHES is operated with constant speed but it can also be operated with variable speed.

48

Pumped Hydro Energy Storage for Hybrid Systems

Figure 3.3 A typical type of reversible pump-turbine unit (Rufer, 2018).

3.2.1.3.1 Fixed pumped hydro energy storage Fixed-speed turbines are the most widely used turbines in PHES systems across the world with the reversible single-stage Francis pump-turbine being an example. The single unit acts as a pump in one direction and as a turbine in the other direction. Fig. 3.4 shows the systemic diagram of the fixed-speed PHES plant where the synchronous machine is connected to the electricity grid through its armature and coupled to the reversible hydraulic machine. The active power is controlled by actuating the turbine control and the governor. The voltage regulation and the reactive power control is done using the excitation system of the synchronous machine (Rufer, 2018). Due to the fixed speed, it is unable to give frequency regulation support to the grid because the pump’s water flow rate is linked to the machine’s rotation speed (Akinyele & Rayudu, 2014). Also, in the turbine operation mode, the unit is unable to function at peak efficiency during part load. These limitations are some of the reasons for the development of the variable speed PHES. 3.2.1.3.2 Variable pumped hydro energy storage Variable-speed PHES systems provide fast power response when compared to the constant/fixed type PHES systems (Rosen, 2020). In the variable-speed turbines, as shown in Fig. 3.5, the power consumed in the pumping mode is varied over a range of outputs, and this allows the plant to perform at maximum efficiency for varying speeds and conditions in order to help improve grid stability (Ardizzon et al., 2014). To achieve

Characteristic features of pumped hydro energy storage systems

49

AVR EXcitor

Tm

HEAD, H

Tunnel and Penstock water Dynamics

FLOW, Q

Tem

Pump Turbine Dynamics

ωr Gate, G

Synchronous Machine

Governor Turbine Control

Grid

P mref

Figure 3.4 Fixed-speed pump-turbine system (Rufer, 2018).

these, there are principally two approaches used in converting energy from the hydraulic shaft to the grid. The simplest approach is the use of a static frequency converter to adapt the variable frequency of the synchronous machine to the frequency of the grid. The static frequency converter transforms the power of the synchronous machine’s stator side where the frequency of the stator is linked to the rotational speed of the machine to the grid with its constant frequency. The second approach used for the variable speed PHES is the doubly-fed induction motor-generator. In this set-up, the electric machine is an asynchronous type. The asynchronous machine’s wound rotor is connected to a frequency converter through the slip rings and brushes, while the stator side is directly linked to the electricity grid. This bidirectional movement, created for the machine’s rotor, makes it practicable to adjust and cover speeds in the hyper- and hypo-synchronous domains (Rufer, 2018). 3.2.1.3.3 Ternary pumped hydro energy storage The ternary PHES plant as shown in Fig. 3.6 has faster response time when compared with convention PHES plants and has a unique configuration in which the motor generator is coupled through the same shaft, either vertically or horizontally, to a separate hydraulic turbine and pump (Ricardo et al., 2020). This configuration is perhaps more expensive (about 20% higher) than the binary type (Komarnicki, Styczynski, & Lombardi, 2017). Typically, Francis and Pelton turbines are mostly used. Francis turbine is a reaction machine with radial flow and it is suitable for medium heads of up to 700 800 m. The Pelton, on the other hand, is an impulse turbine with tangential flow and covers much higher heads

50

Pumped Hydro Energy Storage for Hybrid Systems

uM1,2,3

iM1,2,3

= =

iN1,2,3

uN1,2,3

3

~

~

Grid

3 2

PWM

e-jθN

ejθN

PWM

3

2

2

n

θM

uexc

θN

Current Control

uNd , uNq V/Q Control

fN

Power Control

Current Control

e-jθM

e-jθM

iMd , iMq

uMd, uMq

iexc

=

iNd , iNq

ejθM

ud

~

PLL

DC-Link Control

Tref

ψref

Torque Control

Flux Control

iexc_ref Flux Observer

Power factor Control

Grid side control

Motor/generator side control

Figure 3.5 A schematic diagram of a grid model indicating the main part of the power system enabled by variable PHES (Rufer, 2018). PHES, Pumped hydro energy storage system.

(Rufer, 2018). The ternary PHES is activated by starting the pump, and the load is later transferred gradually to the motor-generator. Both the pump and the turbine can be regulated from 0% to 100% of unit output (Komarnicki et al., 2017).

3.3 Pumped hydro energy storage characteristics and configuration schemes The PHES units have power ratings varying between 100 and 5000 MW and energy storage capacity, which can be in excess of 1000 MWh, but has a very low energy density of 0.5 1.5 Wh/kg and self-discharge of 0.005% 0.02% per day (Benato & Stoppato, 2018). It has a low time of response—in few seconds, a relatively faster start-up time of few minutes (about 3 min) and it can ramp-up from zero to its full load

Characteristic features of pumped hydro energy storage systems

51

Figure 3.6 Example of a PHES ternary turbine (Rufer, 2018). PHES, Pumped hydro energy storage system.

(Benato & Stoppato, 2018). The lifetime of PHES is generally within the range of 30 50 years (Díaz-gonzález, Sumper, & Gomis-Bellmunt, 2016). It has a capital cost of power of 600 2000 $/kW, while the capital cost of energy ranges 5 100 $/kWh (Rosen, 2020). This cost estimate can vary depending on the topology and the orographic nature of the environment as 100 m is at least needed as the elevation requirement between the upper and the lower reservoirs (Díaz-gonzález et al., 2016). A summary of the PHES features is presented in Table 3.1. The round-trip efficiency for PHES systems in practice range between 70% and 87% (Al Zohbi et al., 2016; Rahman et al., 2015; Yang, 2018). The principal losses are generated by viscous drag, turbulence, and friction inside the penstock, pump, and turbine. Other losses are created by the kinetic energy of the water, which is not wholly recuperated in the turbine, and electricity losses in the motor and generator (Komarnicki et al., 2017). The round-trip efficiency of PHES is considered as a function of

52

Pumped Hydro Energy Storage for Hybrid Systems

Table 3.1 Features of pumped hydro energy storage (Benato & Stoppato, 2018; Rahman et al., 2015; Rodrigues, Godina, Santos, Bizuayehu, & Contreras, 2014; Rosen, 2020). S/ N

Features

1

Cost

2 3

Efficiency Electrical capacity

4

Storage/ discharge behavior

5

Lifetime

6

Environment

7

State of the art Applications

8

Value

Unit

Capital cost of power Capital cost of energy Fixed running cost Variable running cost Per-cycle cost

600 2000 5 100 3.8 0.38 0.001 0.014

Round-trip efficiency Power rating Energy storage capacity Power density Energy mass density Self-discharge Depth of discharge Storage time Response time Discharge duration Discharge cycles Lifespan Environmental hostility, pollution, safety Geological requirements Maturity

70% 87% 0.00001 5000 0.0005 24000

$/kW $/kWh $/kWh $/kWh $/kWh/ cycle % MW MWh W/kg Wh/kg % %

Short term (few seconds or minutes), long term (minutes or hours), real long term (many hours to days) Power, energy and bridging applications

0.5 1.5 0.005 0.02 Hours months Sec min 1 hour days 20,000 50,000 30 50 Reservoir

no Years

Reservoir Mature Real long term

Power and energy applications

the pump’s efficiency and the overall efficiency of the turbine as expressed in Eq. (3.1). ηR 5

E out Et 5 5 ηp ηt Ein Ep

(3.1)

Characteristic features of pumped hydro energy storage systems

53

where ηR is the PHES round-trip efficiency, E out is the output energy, E in is the input energy, E t is the energy generated (discharged) by the turbine, E p is the energy utilized by the pump during pumping (charging), ηp is the pump efficiency, and ηt is the turbine efficiency. During the charging or pumping stage, where water is pumped from the lower reservoir section to the upper reservoir, energy is consumed, which is expressed by Eq. (3.2) ρgHV Ep 5 (3.2) ηp where ρ is the density of water (kg/m3), g is the gravitational acceleration (m/s2), H is the height to which the water has to be charged or discharged (m), and V is the volumetric quantity of water to be pumped or discharged (m3). The energy generated when water is discharged through the turbine from the upper reservoir to the lower reservoir is represented by Eq. (3.3). In this situation, the maximum velocity of the mass of water going through the turbine depends on the height considering the position of the upper reservoir. This velocity can be calculated by equating the potential energy of the water in the upper reservoir to the kinetic energy during its discharge at the turbine’s inlet point. This is mathematically expressed through Eqs. (3.4 3.7) E t 5 ρgHV ηt

(3.3)

EPE 5 EKE

(3.4)

EPE 5 mgh; EKE 5 1=2mv2

(3.5)

mgh 5 1=2mv2

(3.6)

vmax 5

pffiffiffiffiffiffiffi 2gh

(3.7)

where EPE is the potential energy, EKE is the kinetic energy, v is the velocity, and m is the mass of water.

3.3.1 Pumped hydro energy storage designs and configuration schemes Pumped hydro energy storage can be integrated with irrigation projects, battery storage, or systems where the river, lake, or ocean is used as the

54

Pumped Hydro Energy Storage for Hybrid Systems

lower reservoir. Different configuration schemes of PHES exist, which allow the integration of more VRE sources into the power system. Fig. 3.7 shows some configuration schemes of PHES. 3.3.1.1 Conventional schemes The conventional PHES ensures rapid start-up with adjustable output power depending on demand requirement. It has the capacity to integrate surplus generated VRE in the power system while minimizing losses. Traditional hydropower plants can be modernized or retrofitted with pumping systems to incorporate PHES capabilities. PHES is seen as a flexible energy storage system because of its functionality over a broad timescale range (IRENA, 2020). 3.3.1.2 Hybrid or coupled schemes (pumped hydro energy storage 1 variable renewable energy) The various energy resources can be amalgamated to build a hybrid energy system, which can complement the drawbacks in each single-energy solution. Consequently, the design goals of hybrid or coupled systems include minimizing generation cost, emissions reduction, energy purchase from the grid (if connected), increasing system reliability, flexibility, and stability, minimizing total life cycle cost, etc. (Sim & Ramos, 2020). VRE technology coupled with PHES can pump water to the upper tank reservoir to minimize curtailment and in such an arrangement, the PHES could be playing a role as a

Figure 3.7 Configuration schemes for PHES. PHES, Pumped hydro energy storage system.

Characteristic features of pumped hydro energy storage systems

55

behind-the-meter battery. Different schemes of this hybrid system could be VRE with PHES as storage on site or VRE technologies incorporated into PHES facility (IRENA, 2020). VRE with PHES as storage on site: In this arrangement, a solar photovoltaic (PV) or wind power plant is installed close to a PHES plant where the PHES functions as on-site storage for the VRE plant due to the intermittency of its supply. A typical set-up of this scheme is as represented in Fig. 3.8, where PHES is coupled with both solar and wind energy system. VRE technologies integrated into PHES facilities: In this arrangement, a floating solar PV system could be installed in the lower or upper reservoir of the PHES plant, thus bringing about a hybrid or coupled system, which can utilize an existing high voltage grid network. These PV systems are installed on the water rather than on the land (see Fig. 3.9), thereby creating other benefits such as significant reduction in the evapotranspiration in the reservoir due to the shading of the reservoir, improved energy yield and cell efficiency of the PV due to the cooling effect of the water, increased productivity and efficiency of water and land use, etc. (Gonzalez Sanchez, Kougias, MonerGirona, Fahl, & Jäger-Waldau, 2021; IRENA, 2020).

3.3.2 Advantages and disadvantages of pumped hydro energy storage Pumped hydro energy storage system has many advantages as its integration in the energy system can guard against outages. It has a comparatively

Figure 3.8 A coupled wind-solar system with PHES on site (Sim & Ramos, 2020). PHES, Pumped hydro energy storage system.

56

Pumped Hydro Energy Storage for Hybrid Systems

Figure 3.9 Floating solar PV system at the Bui hydropower site in Ghana (sourced from the Bui Power Authority webpage1). PV, Photovoltaic.

low capital cost per kWh of energy storage and usually has a long lifetime, which mostly depends on the lifetime of mechanical components. PHES possesses large energy storage capacity which makes it ideal for grid-scale energy storage and could provide black start capability (able to produce energy without requiring an external source of power) as well as frequency regulation. PHES provides system flexibility and makes it easy for deployment with intermittent sources such as wind and solar. There are also drawbacks associated with PHES, which include its relatively lower energy density compared with some other energy storage systems. It is bedevilled with high construction cost and long construction time in comparison to most types of power generation plants. The conventional PHES has several environmental concerns including the destruction of terrestrial wildlife habitat prior to reservoir flooding and disruption of aquatic ecosystem. Additionally, the construction of this type of PHES inevitably destroys land vegetation and trees, especially during the creation of the reservoirs.

1

https://buipower.com/ghana-commissions-first-hydro-solar-hybrid-generating-systemand-floating-solar-pv/

Characteristic features of pumped hydro energy storage systems

57

3.4 Conclusions The utililization of VRE generated electricity requires cost-effective and efficient energy storage systems, which deliver better use of existing power systems, high power quality, and support grid stability. PHES is a matured storage technology, which is efficient and has a long lifetime. It allows the penetration of VRE without jeopardizing network security or necessitating the use of added spinning reserves while making them a competitive energy source. The development of especially nonconventional PHES such as seawater PHES, subsurface PHES, compressed air PHES, etc. has made it possible to be implemented in different geographical locations with minimal environmental concerns. This chapter provides a description of PHES working principle, its classification, characterization, configuration, and pros and cons.

References Akinyele, D. O., & Rayudu, R. K. (2014). Review of energy storage technologies for sustainable power networks. Sustainable Energy Technologies and Assessments, 8, 74 91. Available from https://doi.org/10.1016/j.seta.2014.07.004. Al Zohbi, G., Hendrick, P., Renier, C., & Bouillard, P. (2016). The contribution of wind-hydro pumped storage systems in meeting Lebanon’s electricity demand. International Journal of Hydrogen Energy, 41(17), 6996 7004. Available from https://doi.org/10.1016/j.ijhydene.2016.01.028. Ardizzon, G., Cavazzini, G., & Pavesi, G. (2014). A new generation of small hydro and pumped-hydro power plants: Advances and future challenges. Renewable and Sustainable Energy Reviews, 31, 746 761. Available from https://doi.org/10.1016/j. rser.2013.12.043. Benato, A., & Stoppato, A. (2018). Pumped thermal electricity storage: A technology overview. Thermal Science and Engineering Progress, 6, 301 315. Available from https://doi.org/10.1016/j.tsep.2018.01.017. Díaz-gonzález, F., Sumper, A., & Gomis-Bellmunt, O. (2016). Energy storage in power systems. John Wiley & Sons Ltd. Gonzalez Sanchez, R., Kougias, I., Moner-Girona, M., Fahl, F., & Jäger-Waldau, A. (2021). Assessment of floating solar photovoltaics potential in existing hydropower reservoirs in Africa. Renewable Energy, 169, 687 699. Available from https://doi.org/ 10.1016/j.renene.2021.01.041. Hino, T., & Lejeune, A. (2012). Pumped storage hydropower developments. Comprehensive Renewable Energy, 6. Available from https://doi.org/10.1016/B978-008-087872-0.00616-8. Hunt, J. D., Zakeri, B., Lopes, R., Barbosa, P. S. F., Nascimento, A., Castro, N. J. d, . . . Wada, Y. (2020). Existing and new arrangements of pumped-hydro storage plants. Renewable and Sustainable Energy Reviews, 129(June). Available from https://doi.org/ 10.1016/j.rser.2020.109914. IRENA. Innovative operation of pumped hydropower storage. (2020). ,https://www.irena.org/-/ media/Files/IRENA/Agency/Publication/2020/Jul/IRENA_Innovative_PHS_operation_ 2020.pdf?la 5 en&hash 5 4533ABDD9EA1D0755720FF46F3241FAB56C65014..

58

Pumped Hydro Energy Storage for Hybrid Systems

Kocaman, A. S., & Modi, V. (2017). Value of pumped hydro storage in a hybrid energy generation and allocation system. Applied Energy, 205(June), 1202 1215. Available from https://doi.org/10.1016/j.apenergy.2017.08.129. Komarnicki, P., Styczynski, Z., & Lombardi, P. (2017). Electric energy storage systems— Flexibility options for smart grids. Springer-Verlag GmbH Germany. Rahman, F., Baseer, M. A., & Rehman, S. (2015). Assessment of electricity storage systems. Solar Energy Storage. Available from https://doi.org/10.1016/B978-0-12409540-3.00004-9. Ricardo, M., Vilanova, N., Thiessen, A., José, F., & Perrella, A. (2020). Pumped hydro storage plants: A review. Journal of the Brazilian Society of Mechanical Sciences and Engineering. Available from https://doi.org/10.1007/s40430-020-02505-0. Rodrigues, E. M. G., Godina, R., Santos, S. F., Bizuayehu, A. W., & Contreras, J. (2014). Energy storage systems supporting increased penetration of renewables in islanded systems, 75, 265 280. Available from https://doi.org/10.1016/j.energy.2014.07.072. Rosen, M. A. (2020). A review of energy storage types, applications and recent developments. Journal of Energy Storage, 27(November 2019), 101047. Available from https://doi.org/10.1016/j.est.2019.101047. Rufer, A. (2018). Energy storage-systems and components. CRC Press. Sim, M., & Ramos, H. M. (2020). Hybrid pumped hydro storage energy solutions towards wind and PV integration: Improvement on flexibility, reliability and energy costs. Water, 12(2457). Available from https://doi.org/10.3390/w12092457. Vasudevan, K. R., Ramachandaramurthy, V. K., Venugopal, G., Ekanayake, B., & Tiong, S. K. (2021). Variable speed pumped hydro storage: A review of converters, controls and energy management strategies. Renewable and Sustainable Energy Reviews, 135 (January 2020), 110156. Available from https://doi.org/10.1016/j.rser.2020.110156. Yang, C. (2018). Pumped hydroelectric storage. Storing Energy. Available from https://doi. org/10.1016/B978-0-12-803440-8/00002-6.

Further reading Al-hadhrami, L. M., & Alam, M. (2015). Pumped hydro energy storage system: A technological review, 44, 586 598. Available from https://doi.org/10.1016/j.rser.2014.12.040. Barbour, E., Wilson, I. A. G., Radcliffe, J., Ding, Y., & Li, Y. (2016). A review of pumped hydro energy storage development in significant international electricity markets. Renewable and Sustainable Energy Reviews, 61, 421 432. Available from https://doi.org/10.1016/j.rser.2016.04.019. Chaudhary, P., & Rizwan, M. (2018). Energy management supporting high penetration of solar photovoltaic generation for smart grid using solar forecasts and pumped hydro storage system. Renewable Energy, 118, 928 946. Available from https://doi.org/ 10.1016/j.renene.2017.10.113. Dincer, I., & Abu-Rayash, A. (2020). Sustainability modeling. Energy Sustainability, 119 164. Available from https://doi.org/10.1016/B978-0-12-819556-7.00006-1. Letcher, T. M. (2018). Storing electrical energy. Managing Global Warming: An Interface of Technology and Human Issues, 365 377. Available from https://doi.org/10.1016/B9780-12-814104-5.00011-9. Liu, J., Zuo, J., Sun, Z., Zillante, G., & Chen, X. (2013). Sustainability in hydropower development—A case study. Renewable and Sustainable Energy Reviews, 19, 230 237. Available from https://doi.org/10.1016/j.rser.2012.11.036. Melikoglu, M. (2017). Pumped hydroelectric energy storage: Analysing global development and assessing potential applications in Turkey based on Vision 2023 hydroelectricity wind

Characteristic features of pumped hydro energy storage systems

59

and solar energy targets. Renewable and Sustainable Energy Reviews, 72(January), 146 153. Available from https://doi.org/10.1016/j.rser.2017.01.060. Rogner, M., & Troja, N. (2018). The world ’ s water battery: Pumped hydropower storage and the clean energy transition, December, 1 15. Way, S. N. (2019). Hydropower status report. Xu, B., Chen, D., Venkateshkumar, M., Xiao, Y., Yue, Y., & Xing, Y. (2019). Modeling a pumped storage hydropower integrated to a hybrid power system with solar-wind power and its stability analysis. Applied Energy, 248(March), 446 462. Available from https://doi.org/10.1016/j.apenergy.2019.04.125.

This page intentionally left blank

CHAPTER 4

Impact of market infrastructure on pumped hydro energy storage systems N.S.A. Derkyi1, J.Y. Kusi2, M.A.A. Derkyi1 and Martin Kyereh Domfeh1 1

School of Energy, Department of Renewable Energy Engineering, UENR, Sunyani, Ghana Ho Technical University, Ho, Ghana

2

Contents 4.1 Introduction 4.2 Current market overview and future trends 4.3 Existing market infrastructure and their impact on pumped hydro energy storage 4.3.1 Electricity market for pumped hydro energy storage 4.3.2 Types of market infrastructure for pumped hydro energy storage 4.3.3 Market structure of pumped hydro energy storage at the time of commissioning 4.3.4 Impact of market Infrastructure on pumped hydro energy storage 4.4 Conclusion References

61 64 66 66 67 68 68 70 71

4.1 Introduction The global economy thrives on electricity. However, one of the biggest hurdles faced by players in the electricity industry is maintaining the balance between the demand and supply on the grid infrastructure. If this is not properly handled, it may lead to various forms of power interruptions or even total power outages. Addressing this problem becomes particularly more difficult during peak demand periods (Anuta, Taylor, Jones, ˇ ceki´c, Mujovi´c, & Radulovi´c, 2020). McEntee, & Wade, 2014; S´ In addressing this challenge, engineers deploy electricity-generating systems that can respond rapidly to the surge in demand with minimal or no interruption to the grid supply. This response often involves the deployment of peaking units such as electrical energy storage (EES) Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00004-2

© 2023 Elsevier Inc. All rights reserved.

61

62

Pumped Hydro Energy Storage for Hybrid Systems

systems which include hydropower plants, pumped hydro energy storage (PHES), or gas/diesel power plants. These units should be capable of starting rapidly and reaching their maximum output within the shortest possible time aside from providing the needed energy reserve (Abdellatif, ˇ ceki´c et al., AbdelHady, Ibrahim, & El-Zahab, 2018; Kaplan, 2008; S´ 2020). Sometimes, operators may also balance the demand and supply shortfall by deploying vehicle-to-grid (V2G) technology or demand-side management (DSM) schemes to level the load demand (Anuta et al., ˇ ceki´c et al., 2020). The main disadvantages of gas/diesel power 2014; S´ plants are the high cost of operation and associated negative impacts on the environment (Chua, Lim, & Morris, 2013; Shirazi & Jadid, 2017). The main problems associated with EES technology are the initial installation cost as well as the financial loss incurred between the period of charging and discharging energy, which require specialized market pricing and regulations scheme to ensure value for money in the energy investment (Abdellatif et al., 2018). For over a century now, PHES, being a typical example of EES technology and also referred to as water-battery, has played a crucial role in the power industry by providing the needed demand and supply balancing. Among the EES technology, PHES is considered to be the cheapest and possesses the largest energy storage capacity along with a long lifespan, typically 50 100 years (Blakers, Stocks, Lu, & Cheng, 2021). Currently, PHES supplies about 85% of the global total installed electricity storage capacity of 190 GW (IEA, 2021). PHES plants are generally composed of two interconnected reservoirs at different altitudes. During periods of excess or cheap power, water is pumped from the lower to the upper reservoir. During peak demands, where electricity prices are high, water is made to return to the lower reservoir and by that process, power is generated from the combined operation of a turbine and a generator, as illustrated in Fig. 4.1. In some typical PHES plants, the turbine may play an additional role of a pump through a reverse spinning process (Blakers et al., 2021). Thus, this storage functionality of PHES makes them very versatile in terms of supporting variable or intermittent sources of energy such as wind and solar which are climate-dependent. Generally, PHES systems could offer energy storage support ranging from hours to weeks (Hunt et al., 2020; Koohi-Fayegh & Rosen, 2020). However, PHES has a longer payback period and just like other EES technology systems requires a high upfront investment (Modor Intelligence, 2021). Considered to be the most flexible power alternative for peak demand

Impact of market infrastructure on pumped hydro energy storage systems

63

Figure 4.1 Schematic diagram indicating how pumped hydro energy storage works (IPCC, 2011).

management, the typical efficiency of PHES ranges from 70% to 80% (IEA, 2014; IPCC, 2011; Zhang, Andrews-Speed, & Perera, 2015). The global potential of PHES is estimated to be 23 3 106 GWh in over 600,000 plants (Lu, Stocks, Blakers, & Anderson, 2018), while another study estimates the global total storage capacity of PHES to be 17,325 TWh (Hunt et al., 2020). PHES may be classified into two main groups: conventional riverbased or open-loop PHES and off-river PHES or closed-loop PHES. Conventional river-based PHES, being the commonest and most abundant type of PHES, has two closely connected reservoirs at different elevations with the lower reservoir (often the larger one) receiving river inflow. In contrast, off-river PHES do not receive river inflows though it is also composed of a pair of reservoirs. The energy storage of an off-river PHES plant is generally less than that of conventional river-based PHES; however, the off-river PHES system has other added benefits such as lower flood mitigation cost, higher heads, elimination of negative impacts of damming, rapid construction time, as well as having a greater number of potential sites compared to conventional river-based PHES. On the other hand, the open-loop PHES offers more flexibility as a result of the ˇ ceki´c et al., 2020). Generally, compared to continuous supply of inflows (S´ fossil-based power plants, PHES offers superior benefits: high stability and reliability, longer lifespan, experiences no capacity reduction associated with conventional combustion plants, etc (IRENA, 2012).

64

Pumped Hydro Energy Storage for Hybrid Systems

Due to the massive investment associated with the deployment of PHES, a rigorous and detailed plan is required to ensure its financial viability through conducive pricing in the electricity market. This notwithstanding, the prevailing electricity market is experiencing price volatility as a result of the market liberalization and the immense penetration of renewable energy sources, a situation that has necessitated several research ˇ ceki´c et al., 2020). studies into the current dynamics (S´ This chapter evaluates the varied market structures under which PHES operates with the focus of determining the impact of the market structures on PHES.

4.2 Current market overview and future trends In terms of global composition, PHES comprises about 96% and 99% of the worldwide power storage by capacity and by volume, respectively (Huff, 2015), with Japan, Taiwan, South Korea, United States, and the EU leading in terms of the capacity of installed PHES per capita, as illustrated in Fig. 4.2 (IRENA Renewable Capacity Statistics, 2020). It is forecasted that the PHES market is expected to attain a compound annual growth rate (CAGR) of more than 2% from 2020 to 2025 mainly due to the pressing need to upscale the global energy storage capacity. Closed-loop PHES is expected to dominate the market owing

Figure 4.2 Capacity of pumped hydro energy storage (Watts/person) (IRENA Renewable Capacity Statistics, 2020).

Impact of market infrastructure on pumped hydro energy storage systems

65

Figure 4.3 Projected regional growth rate for the pumped hydro energy storage market for 2020 25 (Modor Intelligence, 2021). Please see the online version to view the color image of the figure.

to its superior benefits when compared to the open-loop type. As of 2018, the Asia Pacific region was leading the PHES market with over 50% of the worldwide installed capacity. This feat is mainly being propelled by the exploits and investment of China in PHES infrastructure. Fig. 4.3 illustrates the projected regional growth rate for the PHES market for 2020 25 (Modor Intelligence, 2021). Using 2021 as the base year, PHES is predicted to constitute about 30% (65 GW) of the world’s hydropower capacity expansion by 2030. This is expected to be driven by the increased need for enhanced grid flexibility as well as higher energy storage demands. In a bid to reduce the initial capital cost linked to PHS, it is forecasted that 7% of PHES capacity additions will make use of existing infrastructure or include pumping capabilities to existing plant reservoirs. The ranking of countries and regions (from the highest to the least) to champion this course of PHS deployment is China, Asia Pacific, Europe, North America, Eurasia, the Middle East, and North Africa. China’s dominant presence in the PHES industry has been fueled by the government’s pressing need to reduce variable renewable energy (VRE) curtailment. Similar reasons have been assigned to the rapidly increasing deployment of PHES in other regions and countries such as Asia Pacific, United States, Australia, and Europe. In other countries such as the United Arab Emirates, Morocco, Egypt, and Iran, the increasing shares of other renewables (solar photovoltaic (PV), wind) is creating an enabling environment for the rapid expansion of the PHES industry across the Middle East and North Africa (IEA, 2021).

66

Pumped Hydro Energy Storage for Hybrid Systems

Though PHES plants are currently reigning in the ESS market, other energy storage technologies are also presently under development (Nadeem, Hussain, Tiwari, Goswami, & Ustun, 2019).

4.3 Existing market infrastructure and their impact on pumped hydro energy storage Researchers are of the opinion that the ability of PHES to offer the needed grid resilience is the major driver for the continuous deployment of the system in the global electricity market (Ghorbani, Makian, & Breyer, 2019). As already indicated, due to the huge capital cost associated with PHES, and also the fact that PHES often operates for a few hours, a robust and carefully designed market infrastructure is required to ensure economic gains.

4.3.1 Electricity market for pumped hydro energy storage Wholesale electricity markets generally adopt either a centralized (power pool) or a decentralized (bilateral contracts) market approach (Barroso, Cavalcanti, Giesbertz, & Purchala, 2005). Under a liberalized climate, there is the bidding for energy services based on prices that have been set after thorough demand and supply auction has been performed. The bidding is done ahead of time daily or hourly. Some advanced markets usually cooptimize the provision of procurement of energy and ancillary services, thus increasing the generator’s profitability along with reduced system cost (Dragoon, 2010; Esmaeili Aliabadi, Çelebi, Elhüseyni, & S¸ ahin, 2021). This approach requires a real-time balancing of demand and supply requirements of the grid in order to maintain system stability and this is done through the balancing and ancillary services market. This also helps to address the shortfalls in the price market (Anuta et al., 2014). Since a liberalized market environment lacks regulation and depends mainly on competition, it tends to suffer higher price volatility (Pollitt, 2007). This situation is a result of the fact that the market prices are dictated by economic and operational factors as well as the option to trade from a vast array of potential sources (Zareipour, Bhattacharya, & Cañizares, 2007). In addressing the challenges pertaining to price volatility, a price cap regulation may be used. However, this may tend to be counterproductive since it may result in imprecise price signals, thus slowing down market responses in the short term whilst hindering long-term market investment (Huneault, 2001).

Impact of market infrastructure on pumped hydro energy storage systems

67

To ensure sustainable financial returns as well as adequate flexibility, a ˇ ceki´c et al. (2020) to novel algorithm of PHES has been developed by S´ provide the needed justification for the high upfront cost of PHES. Data from the Tonstad PHES in Norway were used to assess the performance of the model. Similarly, the market requirement for PHES that can ensure sustainable economic gains during electricity market price fluctuations has been proposed by Salevid (2013). The tool could be used to evaluate the economic viability of PHES plants as well as provide future price forecasts even in a volatile electricity price market.

4.3.2 Types of market infrastructure for pumped hydro energy storage Typically, PHES may operate under any of the following market infrastructures: Liberalized, Regional Monopoly, Regional Monopoly open to Independent Power Producers (IPPs), and National Monopoly. 4.3.2.1 Liberalized market This electricity market category, also referred to as the “deregulated” market, is open to all energy service providers to participate, thus fostering competition and minimizing price hikes and monopoly in the electricity market. The process seeks to attain an overall aim of enhancing social welfare through competition (Dragoon, 2010; Esmaeili Aliabadi et al., 2021). Under a liberalized environment, PHES investors are expected to reap much returns from the provision of ancillary services compared to time-shifting energy arbitrage (Barbour, Wilson, Radcliffe, Ding, & Li, 2016). The attempts to liberate the electricity market birthed the “unbundling” intervention which seeks to detach generation and supply activities from that of the national monopolies, thereby introducing some form of regulation and control as well as enhancing competition in the market (Anuta et al., 2014; OECD/IEA, 2005). 4.3.2.2 Regional monopoly This refers to a market structure where each region is served by a sole utility firm with all the regions being interconnected (Shen & Yang, 2012). 4.3.2.3 Regional monopoly open to independent power producers This electricity market category is similar to the Regional Monopoly, with the difference that only IPPs are permitted to participate in the provision of energy service (Shen & Yang, 2012).

68

Pumped Hydro Energy Storage for Hybrid Systems

4.3.2.4 National monopoly Under this type, a sole state-owned utility company is responsible for the generation, transmission, distribution, and retail of energy services to consumers (Shen & Yang, 2012). It is the oldest and most conventional category of the electricity market until the era of electricity reforms. Pertaining to PHES, before the advent of the liberalized market, stateowned utility companies built and operated PHES to address peak load demands in the supply chain whilst low demand periods were generally catered for by baseload plants (Deane, Ó Gallachóir, & McKeogh, 2010).

4.3.3 Market structure of pumped hydro energy storage at the time of commissioning Several PHES plants have been commissioned and are operating under varied market structures depending on the prevailing electricity market conditions in the country (see Fig. 4.4). From the findings of a study by Barbour et al. (2016), the market structure with the least share of PHES as at commissioning is the Liberalized Market Structure. This is followed by the National Monopoly Market Structure which is generally dominant in Europe. The two leading market structures for the PHES are the Regional Monopoly and the Regional Monopoly open to IPP. The two “superpowers” in the PHES industry, that is China and Japan, are operating most of their PHES infrastructure under the two leading market structures as evidenced in Fig. 4.4. Cumulatively, more than 95% of PHES plants have been commissioned under the three categories of monopoly market structures: national, regional, and regional monopoly that is open to IPPs (Barbour et al., 2016).

4.3.4 Impact of market Infrastructure on pumped hydro energy storage Generally, when the electricity market is liberalized, it promotes the development of PHES projects (Deane et al., 2010), while the inability to “deregulate” or open up the market also comes with its consequences (Ali, Stewart, & Sahin, 2021). Notwithstanding the gains associated with the Liberalized Market Structure, it could as well diminish electricity ˇ ceki´c prices on the market, thus reducing the profitability of PHES (S´ et al., 2020). This is because the advantages derived from PHES extend over both the liberal and the various kinds of the monopolized market, thus making it extremely tough for appropriate incentives to be provided for PHES investors in the liberal market (Taylor, Bolton, Stone, &

Impact of market infrastructure on pumped hydro energy storage systems

69

Figure 4.4 Capacity of pumped hydro energy storage (in GW) operating under different market structures as at commissioning (Barbour et al., 2016).

Upham, 2013). For instance, currently in Germany, the high penetration of wind and solar energy into the electricity market under the liberalized market climate has reduced the wholesale electricity prices, thus hindering the growth and profitability of the PHES industry. PHES in Great Britain and Germany operate under this market environment, that is, the unbundled liberalized market. Under UK’s and Germany’s unbundled liberalized electricity, huge PHES plants are permitted to simultaneously partake in several market services, thus minimizing some potential market risks (Barbour et al., 2016). Globally, liberalization of the electricity industry is increasing (Singh & Chauhan, 2011). In a study by Deane et al. (2010) regarding PHES in the United States, Japan, and the European Union (EU), the authors reported that PHES investment in a liberalized market environment is currently going in the way of repowering, revamping, or constructing “pump-back” PHES instead of the conventional “pure pumped-storage.” This is partly

70

Pumped Hydro Energy Storage for Hybrid Systems

attributable to the fact that most of the new sites for PHES fail the test for economic viability. Again, in a liberalized PHES market setting, there are numerous avenues for remuneration: payment of ancillary services, electricity trading, and capacity payment. The continuous “deregulation” of the electricity market, as in the case of Australia, has been cited as a major driver for the huge investment in PHES. The electricity market for countries such as Switzerland, India, Japan, and China is partially liberalized, while that of the United States consists of both the liberalized markets and partially liberalized markets (Barbour et al., 2016). It has been observed that countries such as China, India, Switzerland, and Japan, which have witnessed major breakthroughs in the development of PHES, have their electricity markets being partially liberalized. In a review study on PHES development by Barbour et al. (2016), the authors revealed that, despite the extensive research and development investment in PHES and ESS as a whole, there is a limit on new investment in ESS which includes PHES. Much of the latest investment in PHES is being groomed under state ownership, that is National Monopoly. This situation is mainly a result of the financial uncertainties and risks associated with the penetration of PHES into a liberalized market. Also, when there is uncertainty regarding the market regulations, it foils investment in PHES (Ali et al., 2021). In markets such as that of Switzerland, Germany, Austria, and China, the PHES industry has seen huge investment due to the foreseable upgrade advantages (Gajic, Stevanovic, & Pejovic, 2019).

4.4 Conclusion The rapid surge in VRE penetration in the electricity market is expected to create a congenial atmosphere for the continuous deployment of PHES plants due to its superior advantage in terms of energy storage and providing grid flexibility. The findings of this chapter reveal that though the liberalized market promotes the development of PHES projects, it could as well diminish electricity prices on the market, thus reducing the profitability of PHES. Also, majority of the existing PHES plants were commissioned under some form of monopolized electricity market structure. Again, it has been observed that countries such as China, India, Switzerland, and Japan, which have witnessed major breakthroughs in the development of PHES, have their electricity markets being partially liberalized. In a nutshell, to foster the development of the PHES industry, robust, transparent, as well as detailed market regulations without any ambiguity are mandatory.

Impact of market infrastructure on pumped hydro energy storage systems

71

References Abdellatif, D., AbdelHady, R., Ibrahim, A. M., & El-Zahab, E. A. (2018). Conditions for economic competitiveness of pumped storage hydroelectric power plants in Egypt. Renewables: Wind, Water, and Solar, 5(1), 1 14. Available from https://doi.org/ 10.1186/S40807-018-0048-1. Ali, S., Stewart, R. A., & Sahin, O. (2021). Drivers and barriers to the deployment of pumped hydro energy storage applications: Systematic literature review. Cleaner Engineering and Technology, 5, 2666 7908. Available from https://doi.org/10.1016/j. clet.2021.100281. Anuta, O. H., Taylor, P., Jones, D., McEntee, T., & Wade, N. (2014). An international review of the implications of regulatory and electricity market structures on the emergence of grid scale electricity storage. Renewable and Sustainable Energy Reviews, 38, 489 508. Available from https://doi.org/10.1016/J.RSER.2014.06.006. Barbour, E., Wilson, I. A. G., Radcliffe, J., Ding, Y., & Li, Y. (2016). A review of pumped hydro energy storage development in significant international electricity markets. Renewable and Sustainable Energy Reviews, 61, 421 432. Available from https:// doi.org/10.1016/j.rser.2016.04.019. Barroso, L. A., Cavalcanti, T. H., Giesbertz, P., & Purchala, K. (2005). Classification of electricity market models worldwide. In International Symposium CIGRE/IEEE PES (pp. 9 16). Available from https://doi.org/10.1109/CIGRE.2005.1532720 Blakers, A., Stocks, M., Lu, B., & Cheng, C. (2021). A review of pumped hydro energy storage. Progress in Energy, 3(2), 022003. Available from https://doi.org/10.1088/ 2516-1083/ABEB5B. Chua, K. H., Lim, Y. S., & Morris, S. (2013). Battery energy storage system for peak shaving and voltage unbalance mitigation. International Journal of Smart Grid and Clean Energy, 2(3), 357 363. Deane, J. P., Ó Gallachóir, B. P., & McKeogh, E. J. (2010). Techno-economic review of existing and new pumped hydro energy storage plant. Renewable and Sustainable Energy Reviews, 14(4), 1293 1302. Available from https://doi.org/10.1016/j.rser.2009.11.015. Dragoon, K. (2010). Enhancing wind energy value. Valuing wind generation on integrated power systems. Elsevier Inc. Esmaeili Aliabadi, D., Çelebi, E., Elhüseyni, M., & S¸ ahin, G. (2021). Modeling, simulation, and decision support. Local electricity markets (pp. 177 197). Academic Press. Available from https://doi.org/10.1016/B978-0-12-820074-2.00017-4. Gajic, A., Stevanovic, V., & Pejovic, S. (2019). Pumped-hydro storages are balancing electric energy production of wind and solar reducing average costs and pollution. International Journal of Fluid Machinery and Systems, 12(1), 47 55. Available from https://doi.org/10.5293/IJFMS.2019.12.1.047. Ghorbani, N., Makian, H., & Breyer, C. (2019). A GIS-based method to identify potential sites for pumped hydro energy storage—Case of Iran. Energy, 169, 854 867. Available from https://doi.org/10.1016/J.ENERGY.2018.12.073. Huff, G. (2015). DOE global energy storage database. Huneault, M. (2001). Electricity deregulation: Doubts brought on by the California debacle. IEEE Canadian Review, 37, 22 26. Hunt, J. D., Byers, E., Wada, Y., Parkinson, S., Gernaat, D. E. H. J., Langan, S., . . . Riahi, K. (2020). Global resource potential of seasonal pumped hydropower storage for energy and water storage. Nature Communications, 11(1), 1 8. Available from https://doi.org/10.1038/s41467-020-14555-y. IEA. (2014). Energy storage technology roadmap technology Annex. IEA. (2021). Hydropower special market report. Available from https://doi.org/10.1787/ 07a7bac8-en.

72

Pumped Hydro Energy Storage for Hybrid Systems

IPCC. (2011). IPCC special report on renewable energy sources and climate change mitigation. IRENA. (2012). Renewable energy technologies: Cost analysis series, hydropower. International Renewable Energy Agency, 1(3/5). IRENA Renewable Capacity Statistics. (2020). No Title. ,https://www.irena.org/publications/2020/Mar/Renewable-CapacityStatistics-2020.. Kaplan, S. (2008). Power plants: Characteristics and costs. DIANE Publishing. Koohi-Fayegh, S., & Rosen, M. A. (2020). A review of energy storage types, applications and recent developments. Journal of Energy Storage, 27(101047). Available from https:// doi.org/10.1016/J.EST.2019.101047. Lu, B., Stocks, M., Blakers, A., & Anderson, K. (2018). Geographic information system algorithms to locate prospective sites for pumped hydro energy storage. Applied Energy, 222, 300 312. Available from https://doi.org/10.1016/J.APENERGY.2018.03.177. Modor Intelligence. (2021). Pumped hydro storage market|2022 27|industry share, size, growth—Mordor intelligence. ,https://www.mordorintelligence.com/industry-reports/ pumped-hydro-storage-market.. Nadeem, F., Hussain, S. M. S., Tiwari, P. K., Goswami, A. K., & Ustun, T. S. (2019). Comparative review of energy storage systems, their roles, and impacts on future power systems. IEEE Access, 7, 4555 4585. Available from https://doi.org/10.1109/ ACCESS.2018.2888497. OECD/IEA. (2005). Lessons from liberalised electricity markets. ,https://iea.blob.core.windows.net/assets/d0c52ee9-6f54-4735-81b2-6e0dd3ddbe13/LessonsNet.pdf.. Pollitt, M. G. (2007). Liberalisation and regulation in electricity systems: How can we get the balance right? [Faculty of Economics]. Available from https://doi.org/10.17863/ CAM.5500. Salevid, K. (2013). Market requirements for pumped storage profitability: Expected costs and modelled price arbitrage revenues, including a case study of Juktan. UPPSALA Universitet. ˇ ceki´c, L., Mujovi´c, S., & Radulovi´c, V. (2020). Pumped hydroelectric energy storage as S´ a facilitator of renewable energy in liberalized electricity market. Energies, 13(22), 6076. Available from https://doi.org/10.3390/EN13226076. Shen, D., & Yang, Q. (2012). Electricity market regulatory reform and competition— Case study of the New Zealand electricity market. In Y. Wu, X. Shi, & F. Kimura (Eds.), Energy market integration in East Asia: Theories, electricity sector and subsidies (pp. 103 139). Jakarta: ERIA, Issue August. Shirazi, E., & Jadid, S. (2017). Cost reduction and peak shaving through domestic load shifting and DERs. Energy, 124, 146 159. Available from https://doi.org/10.1016/J. ENERGY.2017.01.148. Singh, A., & Chauhan, D. S. (2011). Electricity sector restructuring experience of different countries. International Journal of Scientific & Engineering Research, 2(4). Taylor, P. G., Bolton, R., Stone, D., & Upham, P. (2013). Developing pathways for energy storage in the UK using a coevolutionary framework. Energy Policy, 63, 230 243. Available from https://doi.org/10.1016/J.ENPOL.2013.08.070. Zareipour, H., Bhattacharya, K., & Cañizares, C. A. (2007). Electricity market price volatility: The case of Ontario. Energy Policy, 35, 4739 4748. Available from https://doi. org/10.1016/j.enpol.2007.04.006. Zhang, S., Andrews-Speed, P., & Perera, P. (2015). The evolving policy regime for pumped storage hydroelectricity in China: A key support for low-carbon energy. Applied Energy, 150(2), 15 24. Available from https://doi.org/10.1016/j.apenergy. 2015.03.103.

CHAPTER 5

Case studies on hybrid pumped hydro energy storage systems Mathew Anabadongo Atinsia1,2, Williams Amankwah1, Emmanuel Yeboah Asuamah1,2 and Felix A. Diawuo1,2 1

Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana School of Energy, UENR, Sunyani, Ghana

2

Contents 5.1 Introduction 5.2 Configurations of hybrid systems 5.2.1 Hybrid pumped hydro energy storage-wind 5.2.2 Hybrid pumped hydro energy storage-solar photovoltaic 5.2.3 Pumped hydro energy storage-solar-wind hybrid systems 5.3 Existing cases of pumped hydro energy storage hybrid systems 5.3.1 Pumped hydro energy storage-wind and pumped hydro energy storage-solar photovoltaic hybrid systems 5.3.2 Other cases of pumped hydro energy storage system 5.4 Future hybrid pumped hydro energy storage systems 5.4.1 Case study 1: Pumped hydro energy storage coupled with the onshore wind in Gaildorf Germany 5.4.2 Case study 2: Pumped hydro energy storage coupled with solar photovoltaic technology, Hatta, United Arab Emirates 5.4.3 Case study 3: Pumped hydro energy storage coupled with floating solar photovoltaic technology, Kruonis, Lithuania 5.4.4 Case study 4: Pumped hydro energy storage coupled with solar photovoltaic technology in the Atacama Desert, Chile 5.4.5 Case study 5: Pumped hydro energy storage coupled with wind and solar photovoltaic technology, Kidston, Australia 5.5 Conclusion References

73 75 75 77 78 80 80 81 84 84 85 85 85 86 86 87

5.1 Introduction The energy sector is challenged with associated supply issues such as the depletion of fossil fuel resources, increasing energy demand, and global

Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00010-8

© 2023 Elsevier Inc. All rights reserved.

73

74

Pumped Hydro Energy Storage for Hybrid Systems

warming. However, the past years have recorded high consumption of coal, crude oil, and natural gas, leading to global emissions (Ling et al., 2019). The international energy agency (IEA), for instance, reports an emission of 33 GtCO2 from these sources as of 2020 (IEA, 2021a). The Paris agreement is very firm on increasing the share of clean energy resources as well as reducing global warming, most especially from fossil fuels utilization amongst most nations (Li & Chen, 2019). This has provided pathways for considering several key focus areas for decarbonization such as energy efficiency, behavioral change, electrification, renewables, hydrogen and hydrogen-based fuels, bioenergy, carbon capture, utilization and storage, etc. (IEA, 2021b). Renewable energy use is proven to provide a lasting solution to these energy supply issues. However, the major challenges that are facing renewable energy sources (RES) are their intermittency, unpredictability, and weather (seasonal) dependency. The provision of energy storage options for these renewable energy technologies tends to deliver reliable power even if some of the energy sources are not available. Energy storage systems (ESS) allow excess energy to be stored when the power that is generated has exceeded the demand and it can also serve as an energy source when there is an increase in energy demand. Energy storage is an advancing technology that stands to provide support towards sustainable energy development, of which some include enhanced power system reliability, quality and stability, reduced cost of power system and the cost of imbalance charges, reduced power loss, and improved voltage profiles of power systems (Behabtu et al., 2020). The European Union (EU) agrees that ESS will play a key role in the reduction of emissions in the supply side of energy. Energy storage has been applied in several areas such as high power, rapid discharge, and the energy management sector. The high power and rapid discharge encompass the batteries, capacitors, flywheels, and superconducting magnetic energy storage, whereas energy management constitutes compressed air, pumped hydro energy storage (PHES), thermal, etc. Recent reviews highlight the applications of energy storage technologies in lithium-ion (Li-ion) batteries but on a large scale, the PHES is the most matured and widely used energy storage technology (Behabtu et al., 2020). This chapter looks at cases of both existing and proposed future hybridized PHES systems. PHES has been used in different forms to provide options for the operation of power systems and balance the variability of other RES like the wind and the solar. The blend between hydro

Case studies on hybrid pumped hydro energy storage systems

75

storage and variable renewable energy (VRE) provides cost-effective benefits and season complementarities in resources patterns. The innovation of PHES provides services such as load shifting and reduction of renewable curtailment, frequency regulation, fast and flexible ramping, black start, and capacity firming. All these services are made possible by key factors such as the establishment of a favorable regulatory framework, increasing digital operation of PHES systems, investing in public-private research development and deployment projects, and leveraging existing infrastructure by retrofitting PHES facilities (IRENA, 2020).

5.2 Configurations of hybrid systems A hybrid energy system (HES) is a system that implores the principles of more than one energy conversion system. The involvement of different sources of energy in energy conversion makes it relatively robust to overcome limitations more often associated with stand-alone systems (Bombaerts, Jenkins, Sanusi, & Guoyu, 2019). This system inherently supports the integration of cleaner sources of power generation and also advances the optimization of power supply options (Bhikabhai, 2005). The use of hybrid systems, therefore, provides a solution to the intermittent nature of some RES like solar and wind. It allows one source of energy to be used when the other is not available (Koirala & Hakvoort, 2017). Moreover, one technique to strengthen stand-alone solar projects and wind projects is to introduce PHES in their operations. PHESs are the most natural and traditional energy storage and supply technology that have stayed in the system for quite a long time.

5.2.1 Hybrid pumped hydro energy storage-wind The wind-PHES hybrid system proves to be technically and economically viable for different locations globally as it can provide energy storage to fill the gaps caused by intermittent wind supply. The goals and benefits of utilizing these types of systems are to increase the security dynamics, maximize the combined use of wind and hydro energy, optimize the size of the upper reservoir, maximize the recovery of rejected wind farms, and reduce the initial cost of PHES (Javed, Ma, Jurasz, & Amin, 2020). A sampled configuration of a typical PHES-wind hybrid system is shown in Fig. 5.1, where energy is generated from the PHES by releasing water from the upper reservoir to a lower reservoir through the turbine to

76

Pumped Hydro Energy Storage for Hybrid Systems

Figure 5.1 A hybrid pumped hydro energy storage-wind setup (Javed et al., 2020).

generate electricity during peak demand hours. During periods of low demand, the electricity that is generated from the wind turbines is used to pump water from the lower reservoir to the upper reservoir, where the energy is stored in the form of water. To further enhance the reliability of the PHES-wind setup, some proposals have been made for adjustments in its design and operational architecture to include introduction of three reservoirs, the use of hybrid pumped hydro battery storage, scenario-based optimization modeling, controlling wind energy penetration, operational strategy based on reducing wind curtailment, and wind forecasting model for optimal scheduling of next hour operation, etc. (Sim & Ramos, 2020). In terms of the economic viability of PHES, some suggestions have been made to the use of an open well as a lower reservoir to reduce the initial cost of the PHES (Pali & Vadhera, 2018). Some energy supply technology comparisons have been conducted and analyzed using optimization models, and some of the findings indicate that PHES-wind hybrid systems have low operating, maintenance and fuel costs compared to other stand-alone systems, in addition to its ability to maximize RE penetration, minimize fossil fuels in the economy, and maximize wind penetration (Katsaprakakis et al., 2012; Padrón, Medina, & Rodríguez, 2011). Its levelized cost of energy ranges between US$ 0.044/kWh and US$ 0.276/kWh based on factors such as reservoir size, elevation, terrain, and government subsidies (Katsaprakakis & Christakis, 2014). To further elaborate on some of the technological comparative studies, in Oman, the

Case studies on hybrid pumped hydro energy storage systems

77

findings of a study conducted on the—Duqm-Osman PHES-wind system showed that a combination of the wind and the PHES was a more costeffective option than a diesel engine. It further indicated that the cost of energy of the PHES-wind system was very competitive with the open cycle gas turbine and the combined cycle gas turbine. Therefore, it was proposed that for the main interconnected system of the power system in Oman, the PHES-wind hybrid system could help in the transition to a more efficient power system with little dependence on fossil fuel (Albadi, Al-Busaidi, & El-Saadany, 2017). In the case of PHES-wind providing network stability, a spatial analysis was conducted to determine the ideal site for the PHES coupled with a wind farm in the Nova Scotia province in Canada. The study identified five potential sites based on the topographical layout of the province and the environmental and techno-economic cost. The sites were the Barrachois which was ranked the highest, followed by the Digby, Ellershouse, Maryvale, and South Canoe wind energy sites. The study settled on integrating PHES with the wind farm as a useful way of improving the electrical grid stability and gaining a reduced global emission, which was also a target in the province (Collison, 2021).

5.2.2 Hybrid pumped hydro energy storage-solar photovoltaic It is widely known that solar energy is a very clean source of energy but to continuously exploit its delivered energy, it becomes preemptory to introduce a storage system to allow the use of solar-generated energy during the day and night. A typical configuration of PHES-solar PV configuration is shown in Fig. 5.2 where the generated energy from the solar PV panels is fed to the grid while some of the energy generated during offpeak hours is used to pump water from the lower reservoir back to the upper reservoir. The operation of the system relies on the surplus energy after the load demand has been met (Kou, Klein, & Beckman, 1998). The levelized cost of energy (LCOE) for this system setup presently lies between US$ 0.098/kWh and US$ 1.36/kWh, with a payable period of 10 to 15 years. These LCOE values are dependent on factors related to prevailing policies, subsidies, taxes, etc. The PHES blended with photovoltaic, thus, provides a promising option to address the high increasing cost of electricity production (Bellini, 2019).

78

Pumped Hydro Energy Storage for Hybrid Systems

Figure 5.2 A possible hybrid pumped hydro energy storage-solar photovoltaic system (Javed et al., 2020).

A typical case study of the financial evaluation of PHES-solar PV is where a techno-economic assessment of a PHES based 100% renewable energy off-grid HES for electrification purposes was modeled for Djoundé in Northern Cameroon using HOMER (Hybrid Optimization of Multiple Energy Resources) software. It was found that the system had a d 0.256/kWh cost of electricity and d 370.426 net present cost for an 81.8 kW PV system (Yimen, Hamandjoda, Meva’a, Ndzana, & Nganhou, 2018).

5.2.3 Pumped hydro energy storage-solar-wind hybrid systems PHES blended with both wind and solar is an ideal solution to achieve energy sovereignty, increase energy reliability and flexibility while delivering relatively low energy cost. Fig. 5.3 shows a typical setup of a PHESwind-solar hybrid system. The power produced from the solar and wind is used to provide power to pump water from the lower reservoir to the upper reservoir but when there is a high electricity demand, water stored in the upper reservoir is used to generate electricity for use. The process of pumping water to and from the reservoirs can occur simultaneously and is mostly used as a stabilizer for power, voltage, and frequency. For other application purposes, this system provides benefits to some rural areas as it can be used for domestic water and agriculture irrigation (Lin, Ma, & Javed, 2020).

Case studies on hybrid pumped hydro energy storage systems

79

Figure 5.3 A diagram of typical pumped hydro energy storage-solar photovoltaicwind setup (Javed et al., 2020).

Wind solar hybrid system has been used in several regions but has been reconfigured to be complemented with a PHES. An example is a case in the Hunan province, the southern part of China, where the PHES is used to replace the battery with the wind-solar system to achieve economic and social benefits (Li, Wu, Li, Zhou, & Li, 2010). To evaluate the performance of this system reconfiguration, a mathematical model was developed to perform a comparative analysis and simulate the characteristics of the power output using real data of a rural area within the case study province of Hunan over 24 h. The findings of the study showed that the PHES coupled with the wind-solar system could achieve a continuous and stable operation for a day and night with an output power of 0.3 kW and a voltage of 220 V, which was not the case hitherto. Further, the system could generate a power output of 295.5 W during maximum peak hours and a power deviation of 1.8% and a voltage deviation of 1% from the design value. This comparative study showed that the PHESwind-solar hybrid system had the desirable advantages of simplicity, reliability, low failure rate, and the ability to generate constant power. This culminated in the PHES-wind-solar hybrid system providing low energy cost and high-quality electricity (Bendib & Kesraoui, 2019; Chen, Kou, Zou, Pan, & Zhong, 2021).

80

Pumped Hydro Energy Storage for Hybrid Systems

5.3 Existing cases of pumped hydro energy storage hybrid systems 5.3.1 Pumped hydro energy storage-wind and pumped hydro energy storage-solar photovoltaic hybrid systems In this section, the cases of El Hierro Island, which has an installed PHESwind system, and Montalegre, which has PHES-solar PV, are discussed. 5.3.1.1 Case study 1: Pumped hydro energy storage coupled with wind and battery in El Hierro island In 2018, the Spanish El Hierro island increased its renewable energy share in the electricity generation mix to over 54% due to this project. The PHES-wind system as shown in Fig. 5.4 comprises five wind turbines that generate 11.3 MW and are connected to PHES. The facility additionally has a surplus diesel engine, which is used when neither the wind nor water is enough to meet the demand of the people in Ireland. The PHES stores excess energy and produces power when the wind speed is not enough for the generation of the power. The island
s energy demand in August 2019 was completely met by renewable energy for 24 consecutive days (IRENA, 2020). The system is reported to save about 7000 tonnes of fuel, thus having an annual emission savings of 23,000 tonnes of carbon dioxide.

Figure 5.4 Pictorial view of pumped hydro energy storage-wind hybrid system in El Hierro island in Spain (Djunisic, 2020).

Case studies on hybrid pumped hydro energy storage systems

81

Figure 5.5 Pioneer pumped hydro energy storage coupled with floating solar photovoltaic system in Montalegre, Portugal (Osborne, 2017).

5.3.1.2 Case study 2: Pumped hydro energy storage coupled with Solar photovoltaic in Montalegre, Portugal The Montalegre project in Portugal, as shown in Fig. 5.5, is the world’s first constructed hybrid PHES-solar PV (floating) system. This project was designed and built on the dam located at the edge of the Rabagão river. The project was initiated by Energias de Portugal (EDP) in 2015 and completed in 2016. The dam has a total capacity of 68 MWp and costs around d450,000 with an area of 2500 m2. The project additionally adds 220 kWp of floating solar power plants which consist of 840 solar modules (IRENA, 2020). The project is designed to generate power from the solar panel during the day and save hydropower to use during evening peak demand. The project was expected to generate an annual target of 332 MWh of electricity in the first year of its operation, but it generated 5% more power than the targeted annual projection.

5.3.2 Other cases of pumped hydro energy storage system This section highlights some cases of general PHES facilities in Vorarlberg-Austria, Dinorwig-Wales, United Kingdom, La Muela Spain, and Frades II, Portugal.

82

Pumped Hydro Energy Storage for Hybrid Systems

5.3.2.1 Case study 1: Pumped hydro energy storage with ternary systems, Vorarlberg, Austria In 2014, at Vorarlberg, Austria, a PHES with a three ternary system was installed in the Kops II section to have a parallel operation of the turbine and the pump. The units consisted of 180 MW turbine and 150 MW pump (IRENA, 2020). The system has a wide range of ancillary services and is considered to be fast as it can reach a full load in 20 30 s. 5.3.2.2 Case study 2: Conventional pumped hydro energy storage, Dinorwig, Wales, United Kingdom This facility, as shown in Fig. 5.6, is the largest PHES in Europe with six 300 MW reversible turbines and has a storage capacity of 11 GWh (IRENA, 2020). This project is intended to step in when there is a shortage of power and when there is a peak demand for electricity. Due to its fast response time of 16 s to reach full load, it can provide a quick response when there is a quick change in the demand, for example, when domestic consumers at a commercial break during a “TV pickup” simultaneously use high energy consuming appliance such as electric kettles. This causes a surge in energy demand. Dinorwig PHES is able to provide black

Figure 5.6 The Dinorwig power station (NS Energy, 2021b).

Case studies on hybrid pumped hydro energy storage systems

83

start services to contain the situation (IRENA, 2020; Power Technology, 2021a). 5.3.2.3 Case study 3: Conventional pumped hydro energy storage, La Muela, Cortes de Pallás Reservoir, Spain The La Muela PHES system, as shown in Fig. 5.7, is located at the Cortes de Pallás reservoir in the Valencia province of Spain. The PHES was constructed between the years 1983 and 1988, and has a total generating capacity of 1.517 GW with seven reversible turbines (IRENA, 2020). The facility provides a total of 400,000 households with an average annual energy output of around 1625 GWh (IRENA, 2020). The La Muela PHES allocates 40% of its production for ancillary services for real-time system management (Di Stefano et al., 2020). 5.3.2.4 Case study 4: Pumped hydro energy storage with variable speed turbines-Frades II, Portugal The PHES system in Frades II, Portugal has a plant capacity of 780 MW and has variable speed turbines with doubly-fed induction machines. It is

Figure 5.7 Cortes Pallas Reservoir, Cortes de Pallas, Valencia, Spain (NS Energy, 2021a).

84

Pumped Hydro Energy Storage for Hybrid Systems

one of the few facilities with variable speed turbines which is made to run for added flexibility. This delivers higher efficiency, wide operating range, and faster response in the PHES system. The facility provides frequency regulation and voltage stability to the grid with wind generation of about 20% (IRENA, 2020).

5.4 Future hybrid pumped hydro energy storage systems In this section, some future deployment of PHES projects and schemes are presented. Several cases of the PHES hybrid system have been spotted to be available in future. Some of such cases are discussed next.

5.4.1 Case study 1: Pumped hydro energy storage coupled with the onshore wind in Gaildorf Germany This is a pilot project at Gaildorf, Germany where the PHES is coupled with onshore wind. The foundation of the wind turbines is used as the PHES upper reservoir. The wind farm is situated in the Limburg hills and has a generating capacity of 13.6 MW, while the PHES in the valley can deliver a power of up to 16 MW (IRENA, 2020). The electrical storage capacity of the PHES is designed for 70 MWh, and its response time of switching between the energy generation and energy storage is 30 s (Frydrychowicz-Jastrze˛bska, 2019). Some other specifications of the project are presented in Table 5.1. The project is funded by the German Federal Ministry of Environment, Nature Conservation, Construction, and Reactor Safety (BMUB) from the Environmental Innovation Program with an amount of 7.15 million euros. Table 5.1 Specifications of the pumped hydro energy storage-wind hybrid project in Gaildorf (Colthorpe, 2017). Parameters

Specification

Wind turbine capacity Rotor diameter Annual electricity generation from wind power Turbine hub height (HH) above ground Pumped storage capacity Waterfall height Water volume Active reservoir Passive reservoir

4 3.4 MW 137 m 42 GWh Up to 178 m HH 16 MW 200 m 120,000 m3 Up to 40 m 8 13 m

Case studies on hybrid pumped hydro energy storage systems

85

5.4.2 Case study 2: Pumped hydro energy storage coupled with solar photovoltaic technology, Hatta, United Arab Emirates The PHES facility expected in Hatta, United Arab Emirates (UAE) will have a power capacity of 250 MW and it will use surplus electricity from the planned 5 GW Mohammed bin Rashid Al Maktoum Solar Park, the world’s largest solar PV installation (IRENA, 2020). This project will be the first of its kind in the Arabian Gulf region with an investment cost of $391 million. The PHES will store water from the Hatta dam to generate electricity during peak hours when the sun cannot meet the demand of the area (NS Energy, 2021c). The plant is designed to have a fast response time from zero and reach 80% of peak capacity within 90 s. This rapid response will assist in balancing the load in the UAE power system, which will be beneficial for the country to reach its renewable energy target of 75% by 2050 (IRENA, 2020).

5.4.3 Case study 3: Pumped hydro energy storage coupled with floating solar photovoltaic technology, Kruonis, Lithuania In Kruonis, Lithuania, the existing 900 MW PHES facility is expected to be coupled to a pilot floating solar PV project, which will deliver a generation capacity of 60 kW but scalable to 200 250 MW. The facility is intended to provide the utility with reliable frequency control and primary reserve services, thus improving its connectivity to the integrated pan-European market (IRENA, 2020). The project is being developed by the Lithuanian state-owned enterprise, the Lietuvos Energijos Gamyba. The project has received a funding of 235,000 euros from the Lithuanian Business Support Agency (LBSA) (Hydro Review, 2019).

5.4.4 Case study 4: Pumped hydro energy storage coupled with solar photovoltaic technology in the Atacama Desert, Chile The Valhalla project situated in the Atacama Desert, Chile is intended to transmit generated power from the 600 MW Cielos de Tarapacá solar PV farm to the 300 MW Espejo de Tarapacá PHES plant to convert it into a dispatchable power plant (Power Technology, 2021b). This project will provide continuous power to fill about 5% of the baseload demand of northern Chile. This will further demonstrate that power generated from a utility-scale solar PV plant can serve as baseload power.

86

Pumped Hydro Energy Storage for Hybrid Systems

5.4.5 Case study 5: Pumped hydro energy storage coupled with wind and solar photovoltaic technology, Kidston, Australia The project at Kidson, Australia is planned to provide a large-scale PHES of 250 MW having 8 h 10 h of storage and then combined with 320 MW solar PV and 150 MW wind (IRENA, 2020). The project is expected to provide dispatchable and reliable renewable energy during peak demand hours (Meyabadi, Fattahi, & Deihimi, 2017). This project will also increase the stability of the local network in northern Queensland by reducing losses associated with the importation of electricity from the grid for the PHES scheme. This scheme has the tendency to reduce the risk associated with overnight electricity price rise when PHES facilities are normally recharging (IRENA, 2020). This project is partly funded by the Australian Renewable Energy Agency (ARENA) to increase the nations experience in planning and building renewable power plants. The project is already in the first phase but if completed will produce energy that is three times the amount of electricity produced from some of the other big solar PV plants in Australia. This will further drive the impetus for more investments in technology (ARENA, 2021). The facility, when completed, will provide approximately 145,000 MWh of renewable energy to the Kidston renewable energy Hub, increasing penetration by 6%. It will provide electricity to about nine million Australian residents who are connected to the National Electricity Market (NEM) of Australia.

5.5 Conclusion PHES is a matured energy storage technology that allows energy to be stored, especially during low demand periods, and then energy is generated during peak demand periods. Due to the numerous advantages of PHES, hybridizing it with different energy conversion technologies such as renewables provides a solution in dealing with its intermittent nature and delivering a reliable energy supply. This chapter largely looked at the importance of HES in relation to PHES, the different configuration types, examples of both existing and future cases of PHES hybrid systems. Some of the findings of the case studies presented on the hybrid PHES indicate that this system, in comparison with other single conversion plants, has a relatively lower cost of energy with hybrid PHES-wind ranging from US $ 0.044/kWh to US$ 0.276/kWh, while hybrid PHES-solar PV ranged

Case studies on hybrid pumped hydro energy storage systems

87

between US$ 0.098/kWh and US$ 1.36/kWh. Further, the system is able to deliver higher efficiency, wide operating range, faster response in the PHES system, while providing frequency regulation and voltage stability to support the grid network. Overall, the hybrid PHES system is an essential component in delivering energy sustainability and can attract more investments in renewables, which can serve as one of the ways to address the global energy supply issues.

References Albadi, M. H., Al-Busaidi, A. S., & El-Saadany, E. F. (2017). Using PHES to facilitate wind power integration in isolated systems—Case study. In 2017 IEEE international conference on industrial technology (ICIT) (pp. 469 474). ARENA. (2021). Kidston solar project (phase 1). Australian Government, Australian Renewable Energy Agency. Australian Renewable Energy Agency. Behabtu, H., Messagie, M., Coosemans, T., Berecibar, M., Fante, K., Alem, A., & Mierlo, J. V. (2020). A review of energy storage technologies’ application potentials in renewable energy sources grid integration. Sustainability, 12, 10511. Bellini, E. (2019). Coupling pumped hydro with renewables and other storage technologies. Pv Magazine - Photovoltaics Markets and Technology. Bendib, C., & Kesraoui, M. (2019). Wind-solar power system associated with flywheel and pumped-hydro energy storage. In 2019 10th international renewable energy congress (IREC) (pp. 1 6). Bhikabhai, Y. (2005). Hybrid power systems and their potential in the Pacific islands. SOPAC Miscellaneous, Report, 406. Bombaerts, G., Jenkins, K., Sanusi, Y., & Guoyu, W. (2019). Energy Justice Across Borders. Chen, X., Kou, P., Zou, S., Pan, Y., & Zhong, L. I. U. (2021). The off-grid wind-PVPHES hybrid system with continuous power at constant voltage. Energy Storage Science and Technology, 10(1), 355 361. Collison, B. (2021). Spatial analysis of pumped hydro energy storage integration with wind farms in Nova Scotia, Canada. Dalhousie Journal of Interdisciplinary Management, 16. Colthorpe, A. (2017). World’s tallest’ wind turbine gets 70MWh of pumped storage near stuttgart. Energy Storage. Di Stefano, F., Cabrelles, M., García-Asenjo, L., Lerma, J. L., Malinverni, E. S., Baselga, S., . . . Pierdicca, R. (2020). Evaluation of long-range mobile mapping system (MMS) and close-range photogrammetry for deformation monitoring. A case study of Cortes de Pallás in Valencia (Spain). Applied Sciences, 10(19). Djunisic, S. (2020). Spain’s El Hierro island finishes 2019 with 54% renewables share. El Hierro island. Frydrychowicz-Jastrze˛bska, G. (2019). The innovative gaildorf wind-water project guarantees reliability of power supply. Innovation in Energy Systems - New Technologies for Changing Paradigms. IntechOpen. Hydro Review. (2019). Floating solar photovoltaic plant to be installed at kruonis pumped-storage plant in Lithuania. IEA. (2021a). IEA, global electricity demand by scenario, 2010 2030. Paris. IEA. (2021b). Net Zero by 2050: A roadmap for the global energy sector. IRENA. (2020). Innovation landscape brief: Innovative operation of pumped hydropower storage. Abu Dhabi.

88

Pumped Hydro Energy Storage for Hybrid Systems

Javed, M. S., Ma, T., Jurasz, J., & Amin, M. Y. (2020). Solar and wind power generation systems with pumped hydro storage: Review and future perspectives. Renewable Energy, 148, 176 192. Katsaprakakis, D. A., & Christakis, D. G. (2014). Seawater pumped storage systems and offshore wind parks in islands with low onshore wind potential. A fundamental case study. Energy, 66, 470 486. Katsaprakakis, D. A., Christakis, D. G., Pavlopoylos, K., Stamataki, S., Dimitrelou, I., Stefanakis, I., & Spanos, P. (2012). Introduction of a wind-powered pumped storage system in the isolated insular power system of Karpathos Kasos. Applied Energy, 97, 38 48. Koirala, B, & Hakvoort, R. (2017). Integrated community-based energy systems: Aligning technology, incentives, and regulations. In Innovation and disruption at the grid’s edge: How distributed energy resources are disrupting the utility business model (pp. 363 87). Kou, Q., Klein, S. A., & Beckman, W. A. (1998). A method for estimating the long-term performance of direct-coupled PV pumping systems. Solar Energy, 64(1), 33 40. Li, N., & Chen, W. (2019). Energy-water nexus in China’s energy bases: From the Paris Agreement to the well below 2 degrees target. Energy, 166, 277 286. Li, R., Wu, B., Li, X., Zhou, F., & Li, Y. (2010). Design of wind-solar and pumped-storage hybrid power supply system, 5. Lin, S., Ma, T., & Javed, M. S. (2020). Prefeasibility study of a distributed photovoltaic system with pumped hydro storage for residential buildings. Energy Conversion and Management, 222, 113199. Ling, Z., Huang, T., Li, J., Zhou, S., Lian, L., Wang, J., . . . Ma, J. (2019). Sulfur dioxide pollution and energy justice in northwestern China embodied in west-east energy transmission of China. Applied Energy, 238, 547 560. Meyabadi, A., Fattahi., & Deihimi, M. H. (2017). A review of demand-side management: Reconsidering theoretical framework. Renewable and Sustainable Energy Reviews, 80 (May), 367 379. NS Energy. (2021a). Cortes-La Muela hydroelectric power complex. NS Energy. (2021b). Dinorwig power station. NS Energy. (2021c). Hatta pumped storage hydroelectric project. Osborne, M. (2017). First ever hydro-electric and floating solar project operating in Portugal. PV Tech. Padrón, S., Medina, J. F., & Rodríguez, A. (2011). Analysis of a pumped storage system to increase the penetration level of renewable energy in isolated power systems. Gran Canaria: A case study. Energy, 36(12), 6753 6762. Pali, B. S., & Vadhera, S. (2018). A novel pumped hydro-energy storage scheme with wind energy for power generation at constant voltage in rural areas. Renewable Energy, 127, 802 810. Power Technology. (2021a). Dinorwig: A unique power plant in the north of wales. Power Technology. (2021b). El Romero Solar Plant, Atacama. Sim, M., & Ramos, H. M. (2020). Hybrid pumped hydro storage energy solutions towards wind and PV integration: Improvement on flexibility, reliability and energy costs. Water, 12(2457). Yimen, N., Hamandjoda, O., Meva’a, L., Ndzana, B., & Nganhou, J. (2018). Analyzing of a photovoltaic/wind/biogas/pumped-hydro off-grid hybrid system for rural electrification in Sub-Saharan Africa—Case study of Djoundé in Northern Cameroon. Energies, 11(10).

CHAPTER 6

Concept for cost-effective pumped hydro energy storage system for developing countries Emmanuel Yeboah Asuamah1,2, Williams Amankwah1, Mathew Atinsia Anabadongo1, Martin Kyereh Domfeh1 and Felix A. Diawuo1,2 1

Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana School of Energy, UENR, Sunyani, Ghana

2

Contents 6.1 6.2 6.3 6.4

Introduction Overview of cost-effective analysis Project viability factors Financial and economic assessment indices of pumped hydro energy storage projects 6.4.1 Performance metrics for determining cost-effectiveness of pumped hydro energy storage plants 6.4.2 Cost comparison of energy storage technologies based on decision maker’s definition of cost-effectiveness 6.4.3 Pumped hydro energy storage financing models 6.4.4 Issues related to pumped hydro energy storage financing and the way forward 6.5 Conclusion References

89 91 91 92 93 95 96 101 101 102

6.1 Introduction Pumped hydro energy storage (PHES) has seen a tremendous increase in development over the years. PHES has proven to be the leading large-scale commercial energy storage technology accounting for over 300 plants installed across the globe (Mckeogh & Deane, 2010). PHES have been installed for varied reasons; some are installed to meet peak demand, others to aid in the transition to renewable

Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00007-8

© 2023 Elsevier Inc. All rights reserved.

89

90

Pumped Hydro Energy Storage for Hybrid Systems

energies, etc. In each of these contexts, PHES has proven to be feasible, both economically and technically. A study conducted by Sivakumar, Das, & Padhy (2014) shows that the operation of PHES results in meeting the peak demand as well as satisfying economic justification after considering the cost associated with pumping energy. Again, using PHES to meet peak demand costs less compared with that from other peak generating plants such as gas and diesel power plants (Sivakumar et al., 2014). As the world begins to transit from the fossil fuel-based electricity sector to a renewable energy-based one, research and development have improved over the years to curtail the issues related to renewable energy integration into the grid. PHES has been used to reduce the impacts of renewable energies on the grid such as safety, efficiency, and stability of the electricity grid (Cavazzini, Houdeline, Pavesi, Teller, & Ardizzon, 2018). This has necessitated further research of the grid storage industry to examine the various technologies and compare the costs and performance. Some of these technologies include pumped storage hydro (PSH), vanadium redox flow batteries, various kinds of lithium-ion batteries, lead-acid batteries, compressed air energy storage (CAES), and hydrogen energy storage system (HESS) (Mongird et al., 2020). Selecting any of these storage technologies to support the high penetration of renewable energies into the electricity grid needs critical review based on several factors ranging from technical, environmental to economic (Mckeogh & Deane, 2010). At the project initiation phase, project selection methods play a crucial role. As a matter of fact, during the project selection phase, the ability to determine the essential criteria for project selection enhances the overall project execution (Souder & Mandakovic, 2016). Cost-effectiveness is an approach comes in handy in determining or selecting one project from several available options. In this approach, several tools or techniques are applied (Gupta, Bhattacharya, Barabady, & Kumar, 2013). An analysis conducted by Klumpp (2016) using three large-scale energy storage technologies comprising pumped hydro, hydrogen storage and compressed air storage, taking into account their potential to perform the task and the energy storage cost, revealed the following: applying levelized cost of electricity (LCOE) pushed the pumped storage plants ahead of the two technologies when planned for short to medium term but applying long-term makes storage compressed air storage the most positive storage technology followed by hydrogen storage. This chapter focuses on the various cost-effective techniques used in selecting

Concept for cost-effective pumped hydro energy storage system for developing countries

91

PHES over other choices. It also discusses the cost and performance metrics that are applied in these scenarios. Finally, the chapter concludes by reviewing the existing financing models available for PHES projects.

6.2 Overview of cost-effective analysis A cost-effective analysis is a tool that is used to compare options based on both costs and effectiveness. This analysis provides opportunities for various interventions to be compared in relation to costs and their effectiveness. In energy storage, this refers to the various energy storage technologies available to support the transition from the fossil-based electricity sector to renewable energy electricity. In addition, a cost-effective analysis also includes the costs associated with the provision of various services. The outcome of this is used in decision-making for service provision (Hulme, 2006). For a consistent and effective breakdown of system costs, the definition of cost components or factors is crucial. When this is not properly followed or done, it will lead to misinterpretation of outcomes or estimates (Mongird et al., 2020).

6.3 Project viability factors Viability for a project refers to the capacity of a project to meet set objectives as well as its ability to generate substantial financial and economic benefits to the stakeholders involved (Kumar, Agarwal, & Kumar, 2021). Nevertheless, financial, and economic viability is not the principal criteria for authorization of all projects. Other factors of interest include technical, institutional, and social risks in addition to the harmful impacts on the environment (Gakkhar & Soni, 2014). Project development, as discussed, goes through several stages before the final implementation. There must be an initial concept or need for which the project turns to follow or address. These steps are taken to keep the project development costs low to minimize losses in case the project turns out be economically unviable (National Renewable Energy Laboratory NREL, 2013). It also helps to clearly define the potential cost of the project and to estimate the quantity of energy generated or saved. Project developers are faced with questions such as: accuracy of the estimates of costs and savings of the project, tendencies for cost over-runs, and the financial justification of the project against other competing interests (Olubimbola, 2018).

92

Pumped Hydro Energy Storage for Hybrid Systems

In addition to economic reasons, project viability is also dependent on some other factors such as environmental and social considerations and these are used to make decisions on whether a particular project should proceed or not (Belgasim, Aldali, Abdunnabi, Hashem, & Hossin, 2018; Gakkhar & Soni, 2014). PHES projects follow similar steps in determining the suitability or feasibility of building such projects or plants. It is important to note that socioeconomics and technical analysis are normally conducted and compared with similar energy storage projects to justify the need to put up such facilities to serve the intended purposes. In summary, the decision makers’ definition of cost-effectiveness of such a project is strongly linked to economic terms such as payback period (PP), IRR, NPV, energy production costs, etc.

6.4 Financial and economic assessment indices of pumped hydro energy storage projects Pumped hydro energy storage projects are ranked and selected as the most cost-effective or optimal project to deliver a specific task based on certain indices that put or summarize the performances of the various projects into perspective. The following are some notable indices used to determine the cost-effectiveness of a PHES project. In other words, they are referred to as the decision makers’ definition of cost-effectiveness. 1. The benefit-cost ratio: This term is expressed as the total discounted benefits divided by the total discounted costs. This highlights the correlation between the relative costs and benefits expressed in financial or qualitative terms of a proposed PHES project. When the benefit-cost ratio is more than one (1), the project is considered to have a positive net present value (NPV) (Adam Hayes, 2019). 2. Initial project costs: These refer to the costs that are experienced throughout the design and construction phases. These may include planning, land acquisition, preliminary engineering, project design, the cost associated with environmental impact report, cost pertaining to staff training related to the project, final engineering, construction costs, etc. Piripitsi and Struss (2018). 3. Payback period: It denotes the time required to recover the resources invested in a project, or to attain the break-even point. This is computed by accounting for the initial cost of investment and the undiscounted cost savings (as a result of energy savings) during the PHES project lifetime (International Energy Agency, 2016).

Concept for cost-effective pumped hydro energy storage system for developing countries

93

4. Internal rate of return: This metric, which could be referred to as rate of return, is applied in financial analysis to compute the viability of potential investments. This metric provides the discount rate value that delivers a NPV, which equals to zero (0). The PHES project is considered to be viable if the IRR is higher than the cost of capital as this generates a higher net cash flows (Magni, 2010). 5. Net present value: This is a technique to estimate the present value of all future cash flows generated by the PHES project, comprising the initial capital investment. It helps to establish which projects are likely to bring the maximum profit. Profitable value is delivered to the investor if the NPV is greater than zero, while economic value is destroyed for the investor if the NPV is less than zero (Crundwell, 2008; Diawuo, Sakah, de la Rue du Can, Baptista, & Silva, 2020; Kumar et al., 2021). 6. Net present cost: The NPC for a project is the sum of all the costs incurred in a project over the term of the evaluation, with the costs being discounted to the base period. The NPC takes into account all cost components including capital investment, nonfuel operation and maintenance costs, replacement costs, energy costs, and any other costs such as legal fees, etc. (NREL, 2016). 7. Levelized cost of energy or electricity: This is a technique used to determine project viability analysis. It discusses the estimates of the revenue necessary to build and operate a generator over a specified cost recovery period (Energy Information Administration EIA, 2021). 8. Avoided cost of energy: When comparing a series of options to determine the least cost, the concept of avoided cost gains extensive applicability (Beecher). This signifies the power plant’s value to the grid. It shows the cost that a generator would incur to deliver electricity displaced by a new generation plant as an estimate of the revenue available to the plant (Energy Information Administration EIA, 2021). 9. Environmental credits and/or subsidies: This refers to credits, subsidies, financial benefits, rights, etc. of environmental nature that is made or otherwise arise from a power project. They are sometimes given in a form of an incentive to organizations to support activities that have less impact on the environment or protect the environment (Arya, 2020).

6.4.1 Performance metrics for determining cost-effectiveness of pumped hydro energy storage plants In a project, the cost involved can be measured in several different ways. The cost determination, which defines decision makers’ definition

94

Pumped Hydro Energy Storage for Hybrid Systems

of cost-effectiveness, takes into consideration various project cost components, which include equipment costs such as hydropower turbines, generators, total installed cost, replacement costs, fixed and variable operating, and maintenance costs (O&M), etc. (IRENA 2012). Defining the cost component parameters is relevant for the effective breakdown of system costs. The cost component parameters are classified under the following headings discussed below. 6.4.1.1 Pumped hydro energy storage installed cost components This cost component comprises the main component of the energy storage systems installed (IRENA, 2020). These components include: 1. Storage balance of system: This takes into account the cost of supporting components such as cabling, switchgear, etc. 2. Power equipment: This looks at the cost of providing communication interface, and software, alternating current (AC) circuit breakers, isolation protection, relays, etc., which is critical for PHES. 3. Controls & communication (C&C): The cost in this category covers the cost of purchasing an energy management system for the PHES and the cost of operating the PHES. It includes annual licensing costs for software. These costs are normally represented as a fixed cost scalable for power and independent of duration. 4. Grid integration: This covers the cost involved in integrating the PHES to the subcomponents into a single functional system. 5. Engineering, procurement, and construction (EPC). This cost component covers engineering and construction equipment, shipping, siting, and installation, and commissioning of the PHES system. 6. Project development ($/kW): This is related to cost components such as power purchase agreements, permitting, interconnection agreements, site control, and financing. 6.4.1.2 The cost associated with pumped hydro energy storage operations The cost under this category covers fixed and variable operations & maintenance (O&M), which is important to keep the PHES system functioning throughout its economic life. Fixed O&M, however, does not change based on energy outputs, such as component parts, scheduled maintenance, and labor and benefits for staff but covers major maintenance overhaul that hangs on output. Variable O&M includes usage-impacted costs related to nonfuel consumables used to operate the PHES system during

Concept for cost-effective pumped hydro energy storage system for developing countries

95

its economic life. It also considers the cost comparison of the energy received from the grid to pump water and the energy generated to the grid network by the PHES and again takes into account insurance fees to hold a policy insurer to cover unexpected and/or unknown risks (IRENA, 2020; Zhang, Xu, Jiao, & Feng, 2018). 6.4.1.3 The cost associated with decommissioning of the pumped hydro energy storage To be able to compare the cost of PHES to other forms of storage systems and select the optimum one, the cost involved in decommissioning the storage plants is considered. In the PHES system, costs associated with the removal of the PHES interconnection from the grid, the deconstruction of PHES for disposal or recycling, and the cost of recycling are measured. It is important to consider the cost of bringing the site back to its normal state, and thus the cost of remediation (Raimi, 2017). 6.4.1.4 Performance of pumped hydro energy storage for costeffectiveness determination The performance of the PHES plant as against the other storage facilities is costed to aid in the comparison process. The performances are rated based on round trip efficiency (RTE), cycle life, response time, duration corresponding to cycle life, and calendar life. These are very important in the running of the PHES plant and the other storage systems. RTE considers the share of net energy that is discharged to the grid to the total energy used to pump water to the upper reservoir, which refers to RTE. Response time on the other hand refers to the time required for the PHES to go from 0% to 100% rated capacity. Cycle life also caters for the number of cycles and the depth of discharge the PHES can provide throughout its lifetime. The maximum lifespan of PHES, regardless of the operating conditions, represents the calendar life whilst the duration corresponding to cycle life (in years) is expressed as the ratio of the cycle life to the number of cycles per year, thus indicating the downtime (Mongird et al., 2020).

6.4.2 Cost comparison of energy storage technologies based on decision maker’s definition of cost-effectiveness LCOE has been used by Klumpp (2016) to compare three different storage systems under three dispatch scenarios: short, medium, and long-term storage. PSH emerged as the best for short-term dispatch scenario with 77 $/MWh, while compressed air storage with 106 $/MWh followed as

96

Pumped Hydro Energy Storage for Hybrid Systems

second best. Hydrogen storage in cavern followed with 272 $/MWh and then hydrogen storage natural gas grid followed with 361 $/MWh. Finally, hydrogen storage with methanation and methane storage in the natural gas grid followed by LCOE of 484 $/MWh. A comparative analysis was performed on high-speed flywheels, ultracapacitors, and batteries based on both cost and fuel economy. The result shows that high-speed flywheels are competitive with ultracapacitors and batteries (Doucette & McCulloch, 2011). This allows for easy decision-making in selecting an energy storage system or technology. According to a report by HydroWIRES, PSH and CAES, when compared with other energy storage technologies, came out to have the least cost of 165 $/kWh and 105 $/kWh, respectively. The analysis included energy to power ratio of 16, balance of plant, and construction and commissioning costs of PSH (Mongird et al., 2019). A detailed cost analysis indices for cost comparison are presented in Table 6.1. LCOE has been used in many studies to compare technologies or systems. It turns to include several economic indicators such as initial cost of investment, maintenance and operation cost, NPV, fuel expenditures (if relevant), and a total power output of the power plant, which also features the sum of all generated electricity. It assesses and compares alternative approaches to energy production over an assumed lifetime. This makes the LCOE a robust energy decision tool to compare technologies or systems. Private sector participation in investing in PHES has increased in recent years. Each private investor has a way of assessing the viability of a project, which may include an assessment based on risks. Nevertheless, they all undergo financial viability and risk assessment (Head, 2008). The role of traditional investors like multilateral development banks and governments has now become more of facilitating and regulatory role, which includes the provision of guarantees and mitigation of social and environmental impacts whereas private investors have begun to play a leading role in hydropower development (Merme, Ahlers, & Gupta, 2014). The viability of the project can be influenced by the level of financial risks it possesses and how they can be mitigated. Fig. 6.1 shows the factors that influence decisions on project financing.

6.4.3 Pumped hydro energy storage financing models The financing of PHES project usually encompasses a blend of actors and financial mechanisms, which can be combined in various ways.

Table 6.1 Annualized cost values of energy storage technologies (Mongird et al., 2019). Storage Technology

Capital Cost ($/kWh)

BOP ($/kWh)

PCS ($/kWh)

C&C ($/kWh)

O&M ($/kWh)

Total ($/kWh)

Sodium-sulfur Li-ion Lead acid Sodium metal halide Zinc-hybrid cathode Redox flow Pumped storage hydro Compressed air Flywheel Ultracapacitor Combustion turbine

$87.25 $43.49 $101.31 $96.18 $42.53 $73.19 $18.03 $11.39 $2,936.04 $6,893.67 $111.39

$3.30 $4.01 $9.74 $3.43 $4.01 $3.30 $0.00 $0.00 $0.00 $1,719.12 $0.00

$11.55 $11.55 $34.09 $12.02 $14.04 $11.54 $0.00 $0.00 $0.00 $6,016.92 $0.00

$17.56 $$11.55 $68.58 $15.80 $27.76 $25.06 $0.00 $0.00 $56.76 $10.22 $0.00

$2.92 $2.91 $2.70 $2.89 $2.91 $3.04 $1.24 $1.30 $76.39 $240.43 $38.07

$122.58 $73.51 $216.42 $130.32 $91.25 $116.13 $19.26 $12.69 $3,069.19 $14,880.36 $149.46

PCS, Power conversion system; BOP, balance of plant; C&C, construction and commissioning; O&M, operations and maintenance.

98

Pumped Hydro Energy Storage for Hybrid Systems

Figure 6.1 Factors that can influence pumped hydro energy storage project financing (Head, 2008).

Figure 6.2 Typical pumped hydro energy storage project finance structure (International Hydropower Association (IHA), 2017).

All financial schemes are a combination of a blend of equity and debt. The viability of PHES project does not have a single financial structure or a mix of actors universally applicable to all projects. PHES and other large hydropower projects are generally financed through a project finance scheme as shown in Fig. 6.2 (International Hydropower Association (IHA), 2017).

Concept for cost-effective pumped hydro energy storage system for developing countries

99

6.4.3.1 Engineering, procurement, and construction model One of the key financing models available for PHES is the EPC model. This financing model normally includes performing the engineering design, acquiring the necessary materials needed for construction, and finally executing the actual construction. These outlined activities are usually prepared by contractors who specialize in EPC and are therefore referred to as EPC contractors. Under this model, the client (owner) goes into an agreement with EPC contractors, who then deliver an operational asset to the client. The owner or the client transfers the cost and risk to the EPC contractor through an arrangement called a lump sum turnkey via an EPC contract (Marquard & Bahls, 2021). 6.4.3.2 Build operate transfer Under this model of project financing, the public sector grantor grants to a private firm the right to develop and operate a facility over a period. In a build operate transfer (BOT) project, the project operator usually generates its revenues through a fee charged to the utility or government rather than tariffs charged to end users (The World Bank Group, 2020). 6.4.3.3 Design-build-operate In the design-build-operate (DBO) finance model, the public sector operator possesses and finances the construction of assets. The private sector under this model takes charge of designing, building, and operating the assets to meet certain approved outputs. Since there is no financing included in this model, it makes the general documentation simpler than a BOT. The DBO normally consists of a turnkey construction contract and an operating contract, or a section added to the turnkey contract that covers the operations. The operator usually takes no or minimal risk in terms of financing. The operator could be responsible for the replacement of parts during the operational period should the need arise (The World Bank Group, 2020). 6.4.3.4 Finance, engineer, lease, and transfer The newly proposed finance, engineer, lease and transfer (FELT) model structure, as shown in Fig. 6.3, enables control of the scheme parameters to remain with the public sector organization. This structure equitably shares the risks involved in the project, reduces up-front expenditure, provides a secured revenue stream for the developer, and enables the government-owned entity to access all energy and ancillary benefits of the

100

Pumped Hydro Energy Storage for Hybrid Systems

Figure 6.3 Typical finance, engineer, lease and transfer finance structure (Mcwilliams, 2017).

project (Mcwilliams, 2017). A key objective of the model is to disassociate revenue relating to the provision of the facility from energy supply and O&M services. The FELT model is suitable for conventional energy priority hydropower, and it is particularly appropriate for the emerging requirements for grid-supporting flexible hydro and pumped storage schemes (Mcwilliams, 2017). 6.4.3.5 Climate financing PHES projects may also be financed through climate financing which involves the use of funds from private, public, and other sources to fund PHES projects with the aim of addressing the impacts of climate change through adaptation and mitigation interventions. Depending on the objective of a PHES project, it could serve both as a climate change adaptation and mitigation intervention. The funds for this category of financing model may be locally, nationally, or transnationally sourced. Between the period 2003 and 2018, an estimated amount of US$ 693 million was invested in hydropower projects through climate financing. Generally, for a project to

Concept for cost-effective pumped hydro energy storage system for developing countries

101

qualify for climate financing, it must ensure sustainability and adequate value for money, address political risk, conform to regulatory regimes, and clearly spell out the intended mandates on climate change in addition to proving its transformation potential. Agencies involved in climate funding of hydropower projects include clean tech fund, scaling up renewable energy in low-income countries program, green climate fund, and global environment facility (Eberhard, Gratwick, Morella, & Antmann, 2016).

6.4.4 Issues related to pumped hydro energy storage financing and the way forward There are several issues related to financing models for PHES due to their shortcomings. One example of a financing model worth noting is the BOT/BOOT (build-own-operate-transfer) model. Governments and utilities dislike this model because they turn to lose control of the development process and have the possibility to end up paying high tariffs for a project that does not suit their needs (Mcwilliams, 2017). Again, developers do not approve of this model because of the high front-end risks and the enormous time and effort needed to bring a project to completion. International Financial Institutions (IFIs) do not like BOT/BOOT as they turn to typically support the government concessionaire even though this has been partly addressed by the private sector arms of IFIs such as the International Finance Corporation (Mcwilliams, 2017). Another reason for disliking BOOT is the lack of security of the revenue stream (Eberhard et al., 2016). Using the findings from five key countries in Sub-Saharan Africa, the World Bank Group in 2016 evaluated efforts of Independent Power Projects. The report enumerated the challenges being faced by policymakers and what can be done to promote sustainable power sector investment. According to the report, to increase private sector participation, governments ought to provide a conducive investment climate within an enabling environment. These conducive investment climate and enabling environmental factors may include long-term contracts through a competitive bidding process, clear and conducive energy sector policies, structures, and regulatory environment (Eberhard et al., 2016).

6.5 Conclusion This chapter has provided a highlight on how PHES plants are costed based on their initial concept stage through to their decommission stage.

102

Pumped Hydro Energy Storage for Hybrid Systems

It emphasizes the importance of cost-effectiveness and how they help in the choice of an energy storage technology. Again, the chapter reviewed financing models through which PHES could be financed. The findings reveal that in other to determine the optimal project among others, it is necessary to follow the development stages in the project which includes economic analysis.

References Adam Hayes. (2019). Benefit-cost ratio (BCR) definition. Investopedia. Arya N. K. (2020). Subject: Environmental economics course code: ECON3029 topic: Pollution tax and environmental subsidies. Beecher, J. A. (1996). Avoided cost: An essential concept for integrated resource planning. Journal of Contemporary Water Research & Education. Belgasim, B., Aldali, Y., Abdunnabi, M. J. R., Hashem, G., & Hossin, K. (2018). The potential of concentrating solar power (CSP) for electricity generation in Libya. Renewable and Sustainable Energy Reviews, 90, 1 15. Cavazzini, G., Houdeline, J. B., Pavesi, G., Teller, O., & Ardizzon, G. (2018). Unstable behaviour of pump-turbines and its effects on power regulation capacity of pumped-hydro energy storage plants. Renewable and Sustainable Energy Reviews, 94 (June), 399 409. Crundwell, F. K. (2008). Finance for engineers: Evaluation and funding of capital projects. Springer-Verlag London Limited. Diawuo, F. A., Sakah, M., de la Rue du Can, S., Baptista, P. C., & Silva, C. A. (2020). Assessment of multiple-based demand response actions for peak residential electricity reduction in Ghana. Sustainable Cities and Society, 59(May), 102235. Doucette, R. T., & McCulloch, M. D. (2011). A comparison of high-speed flywheels, batteries, and ultracapacitors on the bases of cost and fuel economy as the energy storage system in a fuel cell based hybrid electric vehicle. Journal of Power Sources, 196(3), 1163 1170. Eberhard, A., Gratwick, K., Morella, E., & Antmann, P. (2016). Independent power projects in sub-Saharan Africa: Lessons from five key countries. International Bank for Reconstruction and Development/The World Bank. Energy Information Administration [EIA]. (2021). Levelized cost of new generation resources in the annual energy outlook 2021. US Energy Information Administration (January), 1 25. Gakkhar, N., & Soni, M. S. (2014). Techno-economic parametric assessment of CSP power generations technologies in India. Energy Procedia, 54, 152 160. Gupta, S., Bhattacharya, J., Barabady, J., & Kumar, U. (2013). Cost-effective importance measure: A new approach for resource prioritization in a production plant. International Journal of Quality & Reliability Management, 30(4), 379 386. Head C. (2008). The fnancing package. In hydro finance handbook, (prepared by the authors as a companion document for “Hydro Finance Tutorial,” Session 1C of the New Development Track of the HydroVision 2008 Conference). Kansas City MO: HCI Publications. Hulme, C. (2006). Using cost effectiveness analysis: A beginners guide. Evidence Based Library and Information Practice, 1(4), 17. NREL (2016). Hybrid Optimization of Multiple Energy Resources (HOMER). HOMER pro software, developed by the National Renewable Energy Laboratory (NREL).

Concept for cost-effective pumped hydro energy storage system for developing countries

103

International Hydropower Association (IHA). Hydropower fnancing. Presentation at the Asia Clean Energy Forum Deep-Dive Workshop, Manila 5 8 June. (2017). Available at ,https://d2oc0ihd6a5bt.cloudfront.net/wp-content/uploads/sites/837/2017/06/3_ Hydropower-fnancing-.pdf. (Accessed 12.12.20). International Energy Agency. (2016). World energy outlook 2016. https://iea.blob.core. windows.net/assets/680c05c8-1d6e-42ae-b953-68e0420d46d5/WEO2016.pdf. IRENA. (2012). Renewable energy technologies: Cost analysis series. Renewable Energy Technologies: Cost Analysis Series, 1(3/5), 44, Powers. IRENA. (2020). Renewable power generation costs. Abu Dhabi: Published by International Renewable Energy Agency (IRENA) in 2019. Available from https://www.irena. org/publications/2020/Jun/Renewable-Power-Costs-in-2019. Klumpp, F. (2016). Comparison of pumped hydro, hydrogen storage and compressed air energy storage for integrating high shares of renewable energies—Potential, costcomparison and ranking. Journal of Energy Storage, 8, 119 128. Kumar, S., Agarwal, A., & Kumar, A. (2021). Financial viability assessment of concentrated solar power technologies under Indian climatic conditions. Sustainable Energy Technologies and Assessments, 43(December 2020), 100928. Magni, C. A. (2010). Average internal rate of return and investment decisions: A new perspective. Eng. Econ., 55(2), 150 180. Marquard & Bahls AG (2021). EPC (Engineering, Procurement and Construction) Glossary Marquard & Bahls. Mckeogh, E. J., & Deane, J. P. (2010). Techno-economic review of existing and new pumped hydro energy storage plant. Renewable and Sustainable Energy Reviews, 14, 1293 1302. Mcwilliams, M. (2017). Finance, engineer, lease and transfer (FELT)—An innovative alternative for development of hydro. McWilliams Energy, [Online]. Available from http://www.mcw-e.com/FELT-paper20181011R1.pdf. Merme, V., Ahlers, R., & Gupta, J. (2014). Private equity, public affair: Hydropower financing in the Mekong Basin. Global Environmental Change, 24(1), 20 29. Mongird, K., et al. (2019). Energy storage technology and cost characterization report| Department of Energy. US Department Energy (July). Mongird K., Viswanathan V., Alam J., Vartanian C., Sprenkle V., & Baxter R. (2020, December). 2020 Grid energy storage technology cost and performance assessment (p. 117). National Renewable Energy Laboratory (NREL). (2013, February). A framework for project development in the renewable energy sector (pp. 1 24). Olubimbola O. (2018, July). An analysis of factors determining the viability of locally owned construction firms in south west Nigeria by Oladimeji Olubimbola. Piripitsi, T. Z. A. M. Y. V. K., & Struss, C. E. B. (2018). Determination of cost-effective energy efficiency measures in buildings with the aid of multiple indices. Current Sustain. Energy Reports, 5(1), 37 44. Raimi D. (2017, Octubre). Decommissioning US power plants: Decisions, costs, and key issues (p. 53). Sivakumar, N., Das, D., & Padhy, N. P. (2014). Economic analysis of Indian pumped storage schemes. Energy Conversation Managments, 88, 168 176. Souder, W. E., & Mandakovic, T. (2016). R&D project selection models. Research Management, 29(4), 36 42. The World Bank Group. (2020). Concessions build-operate-transfer (BOT) and design-buildoperate (DBO) projects. Zhang, F., Xu, Z., Jiao, B., & Feng, J. (2018). Study on pricing mechanism of pumped hydro energy storage (PHES) under China’s electricity tariff reform. E3S Web Conference, 38.

This page intentionally left blank

CHAPTER 7

Technological advances in prospecting sites for pumped hydro energy storage Komlavi Akpoti1,2, Salomon Obahoundje3,4, Eric M. Mortey5,6, Felix A. Diawuo2,7, Eric O. Antwi2,8, Samuel Gyamfi2, Martin Kyereh Domfeh2 and Amos T. Kabo-bah8 1

International Water Management Institute (IWMI), Accra, Ghana Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana 3 LASMES-African Centre of Excellence on Climate Change, Biodiversity and Sustainable Development, Université Félix Houphouët Boigny, Abidjan, Ivory Coast 4 International Joint Laboratory on Climate, Water, Agriculture, and Energy Nexus and Climates Services (LMI NEXUS), Université Félix Houphouët Boigny, Bingerville, Ivory Coast 5 Earth Observation Research and Innovation Centre (EORIC), UENR, Sunyani, Ghana 6 Faculty of Science and Techniques, Doctoral Research Program in Climate Change and Energy (DRPCCE) of the West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), Université Abdou Moumouni, Niamey, Niger 7 Renewable Energy Engineering Department, UENR, Sunyani, Ghana 8 Department of Civil and Environmental Engineering, School of Engineering, UENR, Sunyani, Ghana 2

Contents 7.1 Introduction 7.2 Pumped hydro energy storage 7.3 Potential sites for pumped hydroelectric energy storage 7.3.1 Traditional (conventional) river-based pumped hydroelectric energy storage 7.3.2 Off-river (closed-loop) pumped hydro systems 7.4 Factors to consider in the pumped hydroelectric energy storage site selection 7.4.1 Geographic and engineering factors 7.4.2 Environmental factors 7.4.3 Economic factors 7.4.4 Social factors 7.5 Models for pumped hydroelectric energy storage suitability modeling/ mapping 7.6 Environmental impacts of pumped hydroelectric energy storage on prospective sites 7.6.1 Land requirements 7.6.2 Water requirements 7.6.3 Impact on fishery industry and aquatic habitat

Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00009-1

© 2023 Elsevier Inc. All rights reserved.

106 107 109 109 109 109 109 110 111 112 112 115 115 115 115

105

106

Pumped Hydro Energy Storage for Hybrid Systems

7.6.4 Cultural, historical, and scenery impacts 7.6.5 Other environmental factors 7.7 Addressing the environmental impacts 7.8 Conclusion References

116 116 116 117 117

7.1 Introduction Global energy demand is increasing rapidly as the world’s population grows, posing a threat to society and the environment (Hussain, Rahman, Sivasengaran, & Hasanuzzaman, 2019). One of the human systems, most immediately affected by climate change, is energy usage. In predicting the future energy demand for a variety of energy sources, there exists the interaction of several factors of uncertainty including population increase, economic growth, differences in the sectoral blend of economies, individual and organizational behavior, as well as the rate of technology advancement (van Ruijven, De Cian, & Sue Wing, 2019). The art of predicting future energy demands has become a central part of every national policy analysis as far as energy-related factors and constraints are concerned (Rosenberg, Lind, & Espegren, 2013). According to the sixth intergovernmental panel on climate change assessment report, anthropogenic activities on the globe are causing an increase in temperature, and thus by the end of the century, the world is most likely to suffer from the associated negative climate change impacts. The most prominent element contributing to climate change is the emission of greenhouse gases, with carbon dioxide (CO2), from the combustion of fossil fuels, being the most significant contributor (Masson-Delmotte et al., 2021; York, 2016). Due to the intermittent nature of renewable energy (RE) sources, the mismatch between demand and supply continues to be a major difficulty for the penetration of RE sources. This situation is, of course, surmountable with energy storage solutions. Electrochemical, pumped hydro, and compressed air are some of the technological options for energy storage. However, batteries that consist of regenerative fuel cells and rechargeable batteries are considered the most suited and cost-effective solutions for sustainable RE technologies (Hussain et al., 2019; Leung et al., 2012). A fifth of the global energy generation is hydropower. Hydropower is the primary source of energy supply for about 55 countries as well as

Technological advances in prospecting sites for pumped hydro energy storage

107

being the only domestic energy source for many countries. As a result, its current contribution to electricity generation is far bigger than that of any other RE source, and its prospects, particularly in developing nations, are enormous (Yuksel, 2010). An enhanced environmental benefit harnessed from hydropower is linked to the fact that there is neither consumption nor contamination of the water resource during energy generation. Profits from the sale of power generated from hydropower plants could be used to fund several social amenities and interventions such as drinking water supply systems, agricultural irrigation projects, navigational infrastructure, recreational amenities, and ecotourism (Yuksel, 2010; Yüksel, 2010).

7.2 Pumped hydro energy storage Pumped hydroelectric energy storage (PHES) utilizes the elevational difference and hence the potential energy of water that has been pumped from a lower elevation reservoir to a higher elevation reservoir. In moving the water from a lower to a higher reservoir, the technology makes use of a cheaper off-peak source of power to effect pumping. To ensure profitability, power is thus generated from the activities of a turbine by allowing the raised water in the higher reservoir to return to the lower elevation reservoir during peak demands when electricity cost is high. Reversible turbine/generator assemblies serve as a pump or a turbine, depending on the situation (see Fig. 7.1). The method is considered to be the most cost-effective way of storing massive quantities of electrical power, although capital costs and geographical constraints are major deciding factors. Almost every PHES power plant’s design depends heavily on the site’s characteristics. If the geography and geology of the area are favorable, a site with sufficient water is considered excellent for the establishment of a PHES plant. Table 7.1 provides the various typologies of PHES. The site selection process, being the first stage in implementing a project, is critical throughout the PHES plant’s life cycle. It is critical to choose the right construction site to maintain economic, social, and environmental benefits. Choosing an unreasonable site may substantially impede the construction process, resulting in additional cost overruns and affecting peaking capacity (Ding, Duan, Xue, Zeng, & Shen, 2015).

108

Pumped Hydro Energy Storage for Hybrid Systems

Figure 7.1 A schematic view of a typical pumped hydroelectric energy storage illustrating the direction of water flow at various modes (Zhu & Ma, 2019). Zhu, B. S., & Ma, Z. (2019). Development and prospect of the pumped hydro energy stations in China. Journal of Physics: Conference Series, 1369(1), 012018.

Table 7.1 Pumped hydroelectric energy storage topologies (Andrade, Kelman, Cunha, de Albuquerque, & Calili, 2020). Typology

Description

T1

This makes use of two existing reservoirs connected to one or more penstocks in addition to a powerhouse which forms a pumped hydropower storage (PHS) scheme This is composed of an existing lake/reservoir connected to a newly built reservoir. The newly built reservoir is often constructed on a flat area with excavation and embankments or a valley or even sometimes depression This is composed of a greenfield pumped hydropower storage constructed within valleys, close-by dams, depressions, or hilltops This sea-based system makes use of the sea as a lower reservoir connected with a new one. Alternatively, the system may be composed of higher elevation basin reservoir linked to cavern as a lower elevation reservoir This multi-reservoir system makes use of the combination of pumped hydropower storage and conventional plants This system has a lower reservoir that receives adequate inflows from a major river This type utilizes an abandoned mine pit reservoir similar to the T2 arrangement

T2

T3 T4

T5 T6 T7

Technological advances in prospecting sites for pumped hydro energy storage

109

7.3 Potential sites for pumped hydroelectric energy storage 7.3.1 Traditional (conventional) river-based pumped hydroelectric energy storage Many extant greenfield pumped hydropower storage systems were created in tandem with traditional river-based hydropower plants. Two reservoirs at varying heights but located not far from each other are formed. The lower reservoir is usually huge and on a major river, while the upper reservoir is smaller and situated further up on the same river or in a hightributary or parallel valley. A substantial amount of water from the river goes through the system, creating power, before flowing down to the river. The recycling of water between the two reservoirs provides an avenue for energy storage. Pumping is done by purchasing electricity at periods when prices are not expensive, such as when demand is low or when other sources of power are abundant. Generation generally takes place during periods of peak demand and high prices. The system of buying power at a low cost and using it to generate power, which is in turn sold at a higher price, is what is termed arbitrage (Blakers, Stocks, Lu, & Cheng, 2021).

7.3.2 Off-river (closed-loop) pumped hydro systems River-based pumped hydro systems account for nearly all extant pumped hydro systems. There are significant environmental and social concerns to damming or changing the dynamics of rivers in many regions. Alternative techniques of establishing pumped hydro systems do not cause large changes to river dynamics. One option is to use subterranean tunnels and powerhouses to connect existing reservoirs (such as old mining sites) that are near together. Surface disruption is minimal when handled with care and the construction period is reduced compared to river-based PHES (Blakers et al., 2021).

7.4 Factors to consider in the pumped hydroelectric energy storage site selection 7.4.1 Geographic and engineering factors Locating a site for PHES can be a daunting task even for the most experienced engineers. It proceeds with a suitable assessment of the site for PHES. The primary requirement is that the site where the PHES is to be

110

Pumped Hydro Energy Storage for Hybrid Systems

situated should store an adequate volume of water compared with the quantity of materials (e.g., rock) used for the reservoir wall construction. Also, there should be a high altitude difference (“head”) between the paired site. The requirement for PHES, however. goes beyond reservoir identification, existing/possible constraints, and technologies assessment, as depicted in Fig. 7.2. Social, economic, and environmental factors play a significant role in site selection for PHES as presented in Fig. 7.3 and are discussed below.

7.4.2 Environmental factors Many environmental factors affect PHES including: • Implementing a pumped hydro project may involve an alteration to either the daily water level or the water flow rate or both. Any of the scenarios would have a deleterious influence on the aquatic environment within a reasonable distance of the project area.

Figure 7.2 Reservoir selection (Carneiro, Matos, & van Gessel, 2019).

Technological advances in prospecting sites for pumped hydro energy storage

111

Figure 7.3 Factors for site selection of pumped hydroelectric energy storage (Nzotcha et al., 2019).

•

• •

•

Sealed ground surface: This refers to a previously dry land surface that will be inundated to create a man-made reservoir with known environmental impacts (e.g., modifications in soil humidity, animal movement). Land cover: The quantity of vegetation to be inundated as a result of the formation of the reservoir, as well as the accompanying carbon dioxide (CO2) release, has a significant environmental impact. Local solar irradiation: Connecting the PHES to a local solar farm as a stand-alone unit (Nzotcha, Kenfack, & Manjia, 2019) would reduce losses by avoiding extensive transmission lines connecting the two systems. Local wind speed: Following recent trends, the process of choosing a location for a pumped hydro project could be influenced by the need to reduce transmission losses or obtain reliable power from a standalone wind farm (Coburn, Walsh, Solan, & McDonnell, 2014).

7.4.3 Economic factors • •

Nearness to power lines: When a PHES project is situated close to power lines, it results in reduced initial investment as well as power losses, thus resulting in improved efficiency and economic returns. Access to road network: Implementing a PHES project requires access to the project site as well as the conveyance of equipment and materials transportation. As a result, building closer to existing road networks is more cost-effective.

112

•

• • • •

Pumped Hydro Energy Storage for Hybrid Systems

The geological condition of the site: The site’s lithology generally dictates the cost involved in siting reservoirs and other crucial infrastructure. Furthermore, unless a reservoir lining is planned, the plant’s roundtrip efficiency will be harmed by the high soil permeability. The head-distance ratio: In PHES, this is the proportion of the gross head to the horizontal distance between the two reservoirs. It specifies the span of the water conveyance and thus the associated cost. The gross head is the difference in elevation between the lowest and highest water levels in the upper and lower reservoirs. This is an important feature of PHES sites since it limits their capacity. The complexity of the civil works involved: This factor also generally has a massive impact on the total cost of the PHES project to be implemented. Seismic considerations: In areas where seismic vibrations are prevalent, there will be the need to implement measures to forestall unwanted incidents. This will thus impact the economic returns on the PHES project.

7.4.4 Social factors •

•

• •

Nearness to an urban area: PHES may serve as a site for tourist attraction and hence it is beneficial for the project site to be situated near an urban area. However, because a PHES consumes a large portion of the land surface area, the plant should not compete with other important land uses such as an urban extension. In such instances, there is the need to maintain a safe distance. Settlement: Sometimes, there may be the need for permanent or temporary settlement of people and facilities to pave way for a PHES project. Detailed accounting and evaluation of people and facilities to be affected are required in such situations. Land use: The implementation of a PHES project will also need to take into consideration the possibility of interfering with cultural or socioeconomic human activities. Potential for a new latent fault: Constructing a high-altitude artificial reservoir could expose nearby communities to a new latent fault, such as downstream flooding.

7.5 Models for pumped hydroelectric energy storage suitability modeling/mapping As suitable site selection of PHES requires consideration of multiple social, techno-economic, and environmental factors, a multicriteria analysis is

Technological advances in prospecting sites for pumped hydro energy storage

113

often required for its evaluation by incorporating each of the necessary factors identified above. A typical example of multicriteria decisionmaking (MCDA) for PHES site selection is shown in Fig. 7.4 and proceeds in three macro steps: (1) defining the problem, (2) decision-making, and (3) recommendation. The problem statement includes the following stages: • Criteria definition: This refers to the identification and definition of a set of social, techno-economic, and environmental factors on which the evaluation is to be performed. This forms the three Sustainable Development (SD) pillars for PHES site selection. • Alternative consideration: This represents options available to compare with the proposed PHES for optimal decision-making. The alternatives can be similar PHES with slightly varying characteristics of the social, techno-economic, and environmental factors. • PHES MCDM problem model: This refers to a matrix of alternatives and the criteria for PHES site selection. Alternatives differ from each other by the numeric or categorical values of their evaluation criteria. • Data collection and pre-processing: This refers to the collection of raw data on criteria and pre-processing for use in MDCM process. A criterion’s values may be numeric or categorical and must be determined for each alternative under consideration. • Quantification models: This refers to the different models used to get a quantitative description of the attributes, which are being measured for the PHES site evaluation. Quantitative models may be formulas or the use of conversion scale to convert categorical variables into numeric variables, etc. The problem definition often ends with an MCDM problem matrix with a numerical input of criteria values for each alternative. The MCDM matrix at this stage has two major issues: (1) all criteria usually have different units and (2) use of linguistic terms sometimes to describe some criteria. These two issues make it impossible to compare any two criteria and the entire MCDM matrix which is crucial to getting a performance matrix. This problem is solved by normalizing or standardizing the criteria values to enable the direct comparison between any two criteria. Normalization or standardization convert criteria values between 0 and 1, allowing the setup of a real performance matrix required for the second step of the MCDM approach. The second phase involves the use of the performance matrix and preference estimation rules to determine the most preferred criteria from

114

Pumped Hydro Energy Storage for Hybrid Systems

Figure 7.4 A typical example of multicriteria decision-making for pumped hydroelectric energy storage site selection (Nzotcha et al., 2019).

the least desired criteria for PHES site selection. The process is usually in three forms: (1) weight estimation of each criterion, (2) building a preference matrix using the performance matrix and the estimated weights, (3) aggregating each alternative’s criteria to determine the most preferred PHES alternative. The Analytical Hierarchical Process (AHP), designed in Saaty and Vargas (2001), has often been used for estimating weight and optimal

Technological advances in prospecting sites for pumped hydro energy storage

115

selection PHES and MCDA of storage energy systems (Kotb et al., 2021; Nzotcha et al., 2019; Olabi et al., 2021). After weight estimation with AHP, ranking of the alternatives by ELECTRE III through (1) computation of concordance matric, (2) computation of discordance matrix, (3) computation of credibility matrix, (4) ascending reorder and descending, and (5) ranking of the alternatives. The sensitivity analysis, which is often the last stage, involves several iterations and priority adjustments aimed at providing a ranking that is based on better PHES sustainability criteria.

7.6 Environmental impacts of pumped hydroelectric energy storage on prospective sites 7.6.1 Land requirements The implementation of a PHES project may result in the inundation of a vast proportion of land that could have otherwise served other purposes. An off-river PHES with the following typical characteristics, viz., 400 m head, 90% generation efficiency, 85% usable water volume, and 20 m depth, will require about 12 hectares of land for both the upper and lower reservoirs per GWh of storage (Blakers et al., 2021).

7.6.2 Water requirements Also, PHES projects may be seen as a potential threat to water supply security as a result of the quantity of water required to satisfy the storage for the initial fill as well as evaporation requirements. For instance, the energy storage volume required for a 27 GWh per million people is equivalent to 27 kl/person. This was the underlining reason for the failed implementation of the proposed Storm King Mountain PHES, which was intended to augment the energy supply of New York (Blakers et al., 2021).

7.6.3 Impact on fishery industry and aquatic habitat PHES may result in inimical consequences to the fish industries and the aquatic habitat as a whole due to the likelihood of fish entrapment and oxygen depletion. This problem of fish entrapment can however be minimized with the use of fish deterrent systems and careful adjustment to the pumping schedule, as in the case of Russell hydropower station. Also, oxygen depletion in the aquatic environment is often caused by the warming of the water due to pumping operations associated with PHES. However, this challenge of oxygen deficit can be ameliorated with the

116

Pumped Hydro Energy Storage for Hybrid Systems

implementation of an oxygen injection system. Oxygen level fluctuations in the aquatic environment generally impact algae and fish growth (Nestler, Don Dennerline, Weeks, Don Degan, & Sykes, 1999). Notwithstanding these negative impacts, PHES projects may also be used as avenues to enhance aeration in situations where perennial drought conditions cause oxygen level fluctuations (Yang & Jackson, 2011).

7.6.4 Cultural, historical, and scenery impacts The siting of PHES projects may also bring untold destruction to several historical and cultural monuments as well as beautiful natural scenes. This was one of the major concerns of stakeholders and environmentalists against the Storm King Mountain PHES, which was never implemented (Birkland, Madden, Birkland, Mapes, & Roe, 2006).

7.6.5 Other environmental factors Other environmental impacts may also be associated with the construction of roads, pipes, or tunnels for water conveyance, a powerhouse and switchyard, and high voltage transmission lines.

7.7 Addressing the environmental impacts Modern PHES projects are currently undergoing a technological evolution to attenuate much of the negative environmental impacts associated with their construction and operation. This technological evolution is making use of new methodologies such as the use of off-stream systems, abandoned quarries, and mines as well as underground reservoirs and groundwater systems. For instance, the off-stream approach eliminates river daming, thus resulting in fewer impacts on the aquatic environment whilst the use of abandoned quarries, mines, and underground reservoirs minimizes the consequences on existing water bodies, though this requires an extensive scientific evaluation to fully comprehend the peculiar hydrological/environmental interaction associated with each project. Furthermore, the use of groundwater resources, instead of surface water resources, results in minimal adverse impacts on fish. Even more enhanced environmental benefits such as aquatic life protection and water quality improvement will be harnessed with the proposed use of wastewater for off-stream PHES projects. This proposed design will come along with a specially designed pumping scheme that promotes aeration whilst the

Technological advances in prospecting sites for pumped hydro energy storage

117

storage could serve as an extended aerobic biological treatment. Also, the need for frequent power transmission upgrades will be reduced with this proposed initiative, since wastewater treatment plants are often located near densely populated cities, which are also characterized by high energy demand (Yang & Jackson, 2011).

7.8 Conclusion As the global community advocates for more RE sources in the generation mix, the need for energy storage interventions such as PHES will continue to remain crucial. This is expected to foster the growth and development of the PHES industry. The selection of PHES is based on several factors: geographic, social, economic, and environmental. Due to the number and complexity of factors considered for this purpose, a MCDA model is often used during the selection process. From our study, it is observed that the implementation of a PHES project may come with several environmental concerns, that is, land and water requirements, impacts on the fishery industry, aquatic habitat, cultural, historical as well as natural scenery. However, we also observed that much of these concerns are being addressed with improvement in PHES technology.

References Andrade, T., Kelman, R., Cunha, T. M., de Albuquerque, L. R., & Calili, R. F. (2020). An integer programming model for the selection of pumped-hydro storage projects. ,http:// arxiv.org/abs/2007.16036.. Birkland, T. A., Madden, S. S., Birkland, T. A., Mapes, J., & Roe, K. (2006, January). Environmental policy in New York state. Governing New York State. Blakers, A., Stocks, M., Lu, B., & Cheng, C. (2021). A review of pumped hydro energy storage. Progress in Energy, 3(2), 022003. Available from https://doi.org/10.1088/ 2516-1083/abeb5b. Carneiro, J. F., Matos, C. R., & van Gessel, S. (2019). Opportunities for large-scale energy storage in geological formations in mainland Portugal. Renewable and Sustainable Energy Reviews, 99, 201 211. Available from https://doi.org/10.1016/j.rser.2018.09.036. Coburn, A., Walsh, E., Solan, P. J., & McDonnell, K. P. (2014). Combining wind and pumped hydro energy storage for renewable energy generation in Ireland. Journal of Wind Energy, 2014, 1 6. Available from https://doi.org/10.1155/2014/415898. Ding, N., Duan, J., Xue, S., Zeng, M., & Shen, J. (2015). Overall review of peaking power in China: Status quo, barriers and solutions. Renewable and Sustainable Energy Reviews, 42, 503 516. Available from https://doi.org/10.1016/j.rser.2014.10.041. Hussain, F., Rahman, M. Z., Sivasengaran, A. N., & Hasanuzzaman, M. (2019). Energy storage technologies. Energy for sustainable development: Demand, supply, conversion and management. Elsevier Inc. Available from https://doi.org/10.1016/B978-0-12-8146453.00006-7.

118

Pumped Hydro Energy Storage for Hybrid Systems

Kotb, K. M., Elkadeem, M. R., Khalil, A., Imam, S. M., Hamada, M. A., Sharshir, S. W., . . . Dán, A. (2021). A fuzzy decision-making model for optimal design of solar, wind, diesel-based RO desalination integrating flow-battery and pumped-hydro storage: Case study in Baltim, Egypt. Energy Conversion and Management, 235. Available from https://doi.org/10.1016/j.enconman.2021.113962. Leung, P., Li, X., Ponce De León, C., Berlouis, L., Low, C. T. J., & Walsh, F. C. (2012). Progress in redox flow batteries, remaining challenges and their applications in energy storage. RSC Advances, 2(27), 10125 10156. Available from https://doi.org/10.1039/ c2ra21342g. Masson-Delmotte, V., P. Zhai, A. Pirani, S. L. Connors, C. Péan, S. Berger, . . . Zhou B. (2021). Summary for policymakers. Climate change 2021: The physical science basis. Contribution of working group I to the sixth assessment report of the intergovernmental panel on climate (Vol. 34, Issue 2, pp. F0003 F0003). Cambridge University Press (In Press). Nestler, J. M., Don Dennerline, M. W., Weeks, G., Don Degan, S. H., & Sykes, J. (1999). Richard B. Russell phase III completion report: Impacts of four-unit pumpback operation (issue January). Nzotcha, U., Kenfack, J., & Manjia, M. B. (2019). Integrated multi-criteria decision making methodology for pumped hydro- energy storage plant site selection from a sustainable development perspective with an application. Renewable and Sustainable Energy Reviews, 112, 930 947. Available from https://doi.org/10.1016/j.rser.2019.06.035, November 2018. Olabi, A. G., Onumaegbu, C., Wilberforce, T., Ramadan, M., Abdelkareem, M. A., & Al Alami, A. H. (2021). Critical review of energy storage systems. Energy, 214, 118987. Available from https://doi.org/10.1016/j.energy.2020.118987. Rosenberg, E., Lind, A., & Espegren, K. A. (2013). The impact of future energy demand on renewable energy production—Case of Norway. Energy, 61, 419 431. Available from https://doi.org/10.1016/j.energy.2013.08.044. Saaty, T. L., & Vargas, L. G. (2001). Models, methods, concepts & applications of the analytic hierarchy process. Springer Science & Business Media, 175, 350. Available from https://doi.org/10.1007/978-1-4615-1665-1. van Ruijven, B. J., De Cian, E., & Sue Wing, I. (2019). Amplification of future energy demand growth due to climate change. Nature Communications, 10(1), 1 12. Available from https://doi.org/10.1038/s41467-019-10399-3. Yang, C. J., & Jackson, R. B. (2011). Opportunities and barriers to pumped-hydro energy storage in the United States. Renewable and Sustainable Energy Reviews, 15(1), 839 844. Available from https://doi.org/10.1016/j.rser.2010.09.020. York, R. (2016). Decarbonizing the energy supply may increase energy demand. Sociology of Development, 2(3), 265 272. Available from https://doi.org/10.1525/sod.2016.2.3.265. Yuksel, I. (2010). As a renewable energy hydropower for sustainable development in Turkey. Renewable and Sustainable Energy Reviews, 14(9), 3213 3219. Available from https://doi.org/10.1016/j.rser.2010.07.056. Yüksel, I. (2010). Hydropower for sustainable water and energy development. Renewable and Sustainable Energy Reviews, 14(1), 462 469. Available from https://doi.org/ 10.1016/j.rser.2009.07.025. Zhu, B. S., & Ma, Z. (2019). Development and prospect of the pumped hydro energy stations in China. Journal of Physics: Conference Series, 1369(1), 012018. Available from https://doi.org/10.1088/1742-6596/1369/1/012018.

CHAPTER 8

Techno-economic challenges of pumped hydro energy storage Samuel Gyamfi1,2, Emmanuel Yeboah Asuamah1,2 and John Ansu Gyabaah1,2 1

Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana School of Energy, UENR, Sunyani, Ghana

2

Contents 8.1 Introduction 8.2 Overview of pumped hydro energy storage 8.3 The main driver for some existing pumped hydro energy storage plants 8.3.1 Europe 8.3.2 Japan 8.3.3 China 8.3.4 United States 8.3.5 India 8.4 Barriers to deployment 8.4.1 Technical and geographical barriers 8.4.2 Economic barriers 8.4.3 Unfavorable policies for pumped hydro energy storage in the electricity market 8.4.4 Environmental barriers 8.4.5 Other barriers 8.5 The way forward 8.6 Conclusion References

119 121 123 123 124 124 125 125 125 126 126 128 130 131 131 133 133

8.1 Introduction Most energy systems today are heavily based on fossil fuels, which have to change for a sustainable future. The notion behind the introduction of more and more renewable energy (RE) into the energy system is to save fuels, which in the short term are fossil fuels and nuclear in some contexts (Mathiesen et al., 2015). The electrical power production has changed significantly, which has increased challenges for reliability and sustainability Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00011-X

© 2023 Elsevier Inc. All rights reserved.

119

120

Pumped Hydro Energy Storage for Hybrid Systems

for off-grid power supply (Aagreh & Al-Ghzawi, 2013). The intermittency and nonuniformity of renewable energies between generation supply limits its integration at large scale, especially when the energy system is autonomous and RE is the primary energy source (Ma, Yang, & Lu, 2014; Ma & Javed, 2019). Several viable solutions have been made to mitigate these challenges, which include demand-side management through load shifting, electrical energy storage (EES), national grids interconnection, etc. Among these possible approaches, EES has been proposed as the most promising solution (Hemmati & Saboori, 2016). EES still has many unexplored areas for research even though it is a developed technology (Ma et al., 2014). The main function of EES in renewable energy systems (RES) is to ensure that power generation is adequate when RE sources are unable to meet the load demand. Nevertheless, having economical and viable energy storage is still a great challenge, especially for an offgrid RES (Javed, Zhong, Ma, Song, & Ahmed, 2020). Pumped hydro storage (PHS) integrated RES has gained much popularity due to low maintenance cost, long life, high energy density, and environment friendliness (Javed et al., 2020). Hydropower technology constitutes an efficient way to temporarily store energy. This has been used for regulation purposes, to manage the variable energy demand and production across a day. It is established that pumped hydro energy storage (PHES) plants constitute the most cost-effective technology for enhancing power regulation capabilities for plant operators, with competitive costs (300 400 h/kW) and a cycle efficiency range of 65% 80% (Pearre & Swan, 2015). Pumpstorage systems are made up of an upper and a lower reservoir. Water is usually pumped from the lower to the upper reservoir during low demand periods. During peak energy demand periods, water is released into the lower reservoir through turbines, to produce electricity. The period of the cycles is typically from one to a few hours. The amount of energy produced mainly depends on the elevation difference between the two reservoirs, and the volume of water involved. This technique thus requires very large water reservoirs (Poulain, de Dreuzy, & Goderniaux, 2018). The utilization of the huge potential of intermittent and random RE sources is significantly limited by their negative impact on the safety, stability, and efficiency of the electricity grid. Curbing these impacts to allow for an increase in green energy production requires PHES to overcome their instability limits to significantly wide their operating range and to further develop their frequency regulation services. For this reason, there is an urgent need to develop a new and innovative concept of pump turbine of PHES, whose design has to be built on

Techno-economic challenges of pumped hydro energy storage

121

in-depth knowledge and a complete understanding of the instabilities affecting the pump-turbine behavior (Cavazzini, Houdeline, Pavesi, Teller, & Ardizzon, 2018).

8.2 Overview of pumped hydro energy storage Pumped hydro energy storage is a well-established and commercially acceptable technology for utility-scale electricity storage and has been used since as early as the 1890s. Hydropower is not only a renewable and sustainable energy source, but its flexibility and storage capacity also makes it possible to improve grid stability and to support the deployment of other intermittent RE sources such as wind and solar (Abdellatif et al., 2018). Pumped storage hydroelectricity (PSH), or PHES, is a type of hydroelectric energy storage used as a means for load balancing. This approach stores energy in the form of the gravitational potential energy of water pumped from a lower elevation reservoir to a higher elevation (Alhadhrami & Alam, 2015). When the water stored at height is released, energy is generated by the downflow, which is directed through highpressure shafts, linked to turbines that are coupled to generators, thus producing electricity. Water is pumped back to the upper reservoir by linking a pump shaft to the turbine shaft, using a motor to drive the pump. This kind of plant generates energy for peak load, and at off-peak periods water is pumped back for future use (Hino, Engineering, & Co, 2012). During off-peak periods, excess power available from some other plants in the system is used for pumping the water from the lower reservoir to a higher reservoir (Aswathanarayana, 2010). A typical layout of a pumped storage plant is shown in Fig. 8.1. PHES that have currently been deployed are of various sizes and different costs depending on the geographical characteristics of the location of the plants. Typical technical characteristics of large PHES currently in operation are summarized in Table 8.1. The cost of PHES is seen as one that is very effective considering the services that they provide. As the interest of the grid storage industry remains, it has become necessary to examine the various technologies and compare their costs and performance on an equitable basis. A study has been conducted to compare the cost of various energy storage technologies for lithium-ion iron phosphate (LFP) batteries, lithium-ion nickel manganese cobalt (NMC) batteries, lead-acid batteries, vanadium redox

122

Pumped Hydro Energy Storage for Hybrid Systems

Figure 8.1 Overview of a pumped hydro energy storage system (Hino et al., 2012). Table 8.1 Typical technical characteristics of pumped hydro energy storage plants. Installed capacity of pumped hydro energy storage plant

10 4000 MW

Discharge duration at rated power Round trip efficiency Self-discharge Response time The capital cost of plant Capital cost of energy Lifetime Suitable storage duration

1 24 h or more 70% 80% Generally negligible Minutes 2000 4000 $/kW 5 100 $/kW 40 60 years or more Several hours to days

flow batteries (RFBs), compressed air energy storage (CAES), PSH, and hydrogen energy storage system (HESS) (bidirectional). The study considered performance matrices like life cycle, round trip efficiency, response time, operating cost, etc. The result shows that PHES has the least projected cost estimate of $262/kWh for a 100 MW followed by battery grid storage solutions with lithium-ion LFP ($356/kWh), lead-acid ($356/ kWh), lithium-ion NMC ($366/kWh), and vanadium RFB ($399/kWh) for a 100 MW (Mongird et al., 2020). A report, published by San Diego County Water Authority and reported by Driscoll (2019), revealed that the highly competitive energy storage technology for large-scale energy storage is pumped storage. A summary of the report is presented in Fig. 8.2. A study conducted by Electric Power Research Institute and reported by the Environmental & Energy Study Institute (2019) showed that in

Techno-economic challenges of pumped hydro energy storage

123

Figure 8.2 Levelized cost of storage comparison.

comparison to other forms of energy storage, PSH can be cheaper, especially for very large capacity storage. It also reported that the installed cost for PSH varies between $1700 and $5100/kW and that of lithium-ion batteries between $2500/kW and 3900/kW.

8.3 The main driver for some existing pumped hydro energy storage plants Over the last few decades, PHES deployment has gained a lot of interest among researchers and power system operators because of the unique advantage of providing large storage for electrical energy. The increasing deployment of RE technologies, particularly wind and solar PV, has necessitated the need to invest in energy storage technologies. Some of the installed PHES across the globe are listed below.

8.3.1 Europe Europe has the installed PHES with varied installed capacities. The majority of the schemes are located in Austria, France, Germany, Italy, Spain, and Switzerland, where there are suitable geographic locations for PHES

124

Pumped Hydro Energy Storage for Hybrid Systems

deployment. Historically, PHES nuclear power was the key driver of PHES installations in many countries but some countries like Austria installed significant PHES capacities, despite having no nuclear power at all. Presently, installed capacity of PHES has slightly increased. This is attributed to increased demand of energy and increased penetration of wind energy. Construction of PHES plant can take a very long time and so factors driving their deployment might have occurred in few years past. The Reisseck II plant (430 MW) in Austria and the expansion of La Muela plant in Spain are amongst Europe’s PHES deployment in the last few years (Barbour, Wilson, Radcliffe, Ding, & Li, 2016).

8.3.2 Japan The main driver of PHES deployment in Japan had been to compliment nuclear power and to provide an alternative to the use of fossil-fueled peaking plants. Japan uses nuclear plants to serve base load. The nuclear plants typically lack flexibility to respond to changing load. For energy security reasons, Japan opted for a large capacity of PHES to complement its nuclear power and provide peak electricity. This adds to the value of flexible generating plants and gives one reason why the percentage of PHES capacity is significantly higher than in many other countries. The mountainous interior of Japan is well suited for PHES, although many of the best sites have now been developed (Barbour et al., 2016).

8.3.3 China Although development of PHES begun in the 1968 and 1975 when the first and second PHES plants were respectively installed, real adoption of the technology occurred recently compared to the happenings in Europe. The recent interest in PHES is a result of rapid increases in economic development and the need to fill the valley-to-peak gap and increase grid reliability. China’s quest to reduce carbon emissions and the increasing wind penetration has been one of the key drivers of PHES investment. Governmental and regional targets for carbon reduction have increased the installed capacity of RE, and pumped hydro is regarded as a way to aid integration. The rapid development of wind energy in north and west China with insufficient transmission infrastructure can also be considered as a significant driver for increased PHES development.

Techno-economic challenges of pumped hydro energy storage

125

China’s high share of coal-based power generation is another driver for more flexible generation, as most plants are large scale and less efficient and less economic to operate at partial load (the economic factors are exaggerated by high coal prices). The increase in PHES capacity is occurring alongside significant expansions of conventional hydro generation (Al-hadhrami & Alam, 2015).

8.3.4 United States The majority of PHES installed in the United States were constructed between 1960 and 1990, when there was significant increases in the capacity of nuclear power. The energy crises in the 1970s also played a significant role in increased investments in PHES during that period. The hike in prices of oil at the time of the energy crisis made investments in PHES a good alternative for managing demand. Subsequent decreases in the price of oil and gas as well as large decreases in the capital costs of combined cycle gas turbine peaking units then led to a hiatus in energy storage interest and since 1990 there has been minimal deployment of PHES in the United States (Barbour et al., 2016).

8.3.5 India India’s first pumped storage plant of 770 MW was fully commissioned in 1981. Between 1981 and 1998 a further 742 MW of PHES was added, and an additional 3450 MW was added between 2003 and 2008. The motivation to use pumped hydro in India comes primarily from the desire to meet peak electrical demand; the peak power capacity is short of the peak demand in most states by 10% 15%. The aim for pumped hydro plants is therefore to shift electricity from off-peak to peak hours. However, most PHES plants have been unable to perform to their full potential due to insufficient availability of off-peak electricity, which is often less than the pumping capacity of the plants. This has meant that many mixed PHES stations have achieved much less than their designed pumping time, and thus their energy output has been lower than projected (King, 2015).

8.4 Barriers to deployment Pumped hydro energy storage plants represent an ideal solution for the intermittent and random nature of renewable energies because of their ability to provide large storage capacity with excellent grid connection

126

Pumped Hydro Energy Storage for Hybrid Systems

properties, high cycle efficiency range, and competitive costs (Cavazzini et al., 2018). However, PHES have to increase their operation at part loads and be able to switch fast and frequently between pump and turbine modes when necessary. Unfortunately, pump turbines suffer from behavior instabilities, thereby constituting a limit when considering their exploitation in a wider continuous working range. This calls for a definition of a new concept of pump turbines able to provide the full benefit of regulation in pumping mode and a wide range of power in generation mode to increase the exploitation of RE sources (Cavazzini et al., 2018). The barriers considered under this study are categorized and summarized as follows:

8.4.1 Technical and geographical barriers Undoubtedly, wind energy production, supported by PHES, increases the stability of the power network. However, locating a suitable site for PHES can be a major challenge because of the technical design and specifications. For instance, in China, most of the suitable sites for PHES are located in the southwest section of the country while wind resources are located mainly in the northern part. The resources are generally separated by several miles (Ming, Kun, & Daoxin, 2013). PHES facilities require very specific site conditions to make the project viable, that is, high head, favorable topography, good geotechnical conditions, access to the electricity transmission networks, and availability of water. The most important selection criteria are the availability of locations with a difference in elevation and access to water (Mckeogh & Deane, 2010). As more and more PHES were developed, the best available locations continued to decline just like in the case of conventional hydro plants. The development trend of PHES in many countries indicates that the majority of plants were built between 1960 and 1980 (Mckeogh & Deane, 2010). This was in part due to a rush for energy security and nuclear energy after the oil crises in the early 1970s. Subsequently, there was a decline in the 1990s partly because of a limited number of feasible sites (most cost-effective) and partly due to a decline in the development of nuclear plants (Mckeogh & Deane, 2010).

8.4.2 Economic barriers The cost of investing in PHES is an important economical parameter and affects the total cost of energy production. The investment of PHS is still

Techno-economic challenges of pumped hydro energy storage

127

costly, which is usually higher than conventional generation resources, for example, coal- or nuclear-fired power plants (Ummels, Pelgrum, & Kling, 2008). The cost of PSH project costs is known to vary based on site-specific conditions such as site geology ranging from water availability, access to the transmission grid, and overall cost of construction. The cost of a feasible project site can range from $1500/kilowatt (kW) to $2500/kW, using an estimated 1000 MW-sized project as a case study. The cost, however, varies from project size to project size. A relatively smaller project does not usually have the same economies of scale and could result in higher unit costs (in $/kW) than a large project. These costs are cover all project aspects except transmission interconnection charges, which can range from very minor charges to several hundred million dollars, based on factors such as existing line capacity or size and distance of new lines (NHA’s Pumped Storage Development Council, 2018). A study conducted by Electric Power Research Institute (2010) reported that the levelized cost of pumped storage and CAES, which remains the only other large grid-scale energy storage technology, represents the lowest cost forms of energy storage technologies, as shown in Fig. 8.3. However, this is still on the high side compared to other conventional generation resources.

Figure 8.3 Levelized cost of energy storage systems.

128

Pumped Hydro Energy Storage for Hybrid Systems

NREL (2018) conducted a survey to identify market opportunities and challenges for pumped hydro in an evolving power grid and stated that the most notable challenge is related to estimating how much revenue will be received for providing nonenergy services to a grid. They conducted nine scenarios, and it was difficult to determine any sort of pattern relating system cost savings provided to PHES net revenue received. Many developers and stakeholders admit that it is uneconomical to build new PHES plants in the present legal and regulatory framework. Even when they are willing to invest in large electricity storage facilities, they explain that access to finance is difficult because of the various regulatory and market uncertainties that have a possible negative impact on profitability (Táczi, 2016).

8.4.3 Unfavorable policies for pumped hydro energy storage in the electricity market Pumped hydro energy storage projects require huge initial capital injection and so a careful policy aimed at encouraging its development must be pursued. In the absence of proper incentives, investors in the electricity market would not be encouraged into PHES development. Ownership of PHES projects varies from country to country, but the key underlying factor is incentives. China’s policy on PHES offers an incentive to grid companies to invest in and own PHES plants, and does not encourage other independent participants. The grid companies are expected to recoup their investments by integrating the investment cost into the normal operating cost of the grid. A study by Barbour et al. (2016) classified the revenue streams for EES into three main models, depending on the size of the specific EES, and further indicated that a particular EES can partake in all the revenue models. The first of the revenue model is the “cost of service model.” This model allows the remuneration of the cost of the project in a regulated manner over an agreed period. The project owner and the regulator set the return on the capital of the project with an appropriate rate of return together with operational cost. This approach is mainly used in markets where the PHES providers enjoy a monopoly and this does not allow for easy individual participation (Barbour et al., 2016). Many regulators in the electricity market are reluctant in adopting this business model because it is considered to give undue advantage to EES operators since they can also derive revenue from the competitive market in addition to the agreed remuneration.

Techno-economic challenges of pumped hydro energy storage

129

PHES has the potential in today’s electric market as it can bring an added value through additional services, beyond the time-shift of energy delivery. Nevertheless, the lack of strong national energy policy may lead to changing independent system operators (ISO) market rules and product definitions that may have a significant impact on the value of additional services, including those related to energy storage (NHA’s Pumped Storage Development Council, 2018). Energy demand response strategies and energy storage systems that fall under nongenerating resources do not have tariff and market rules to fully participate in established markets. However, these are typically real-time or day-ahead markets. Yet, there are no long-term value streams where a bulk storage project can attract investors seeking revenue certainty through long-term power purchase agreements or defined value streams (Electric Power Research Institute, 2010). PHES plants are not considered as RE sources in the European Energy Directive. Meanwhile, this technology has been an effective tool to facilitate the integration of intermittent RE sources (Táczi, 2016). The significant growth in the penetration of RE sources stresses the need for change in policy (Rangoni, 2012). There are no clear policy guidelines for PHES, as they are seen as an electricity consumer and an electricity generator depending on its operation and equipment. And thus, PHS pays in most EU countries double fees (tariffs) for network access, some TSOs charge nothing for the PHS’s role as electricity consumer, and other TSOs recognize it as a renewablebased generator (country survey results in European Commission, n.d.). In the US market, three main schemes of revenue sources are defined for all EES developers (Sioshansi, 2017); the first model is a price-based scheme which allows the EES developer to operate in a competitive wholesale market to recoup the investment. The EES has the opportunity to provide energy services at the prevailing wholesale electricity prices determined by the market forces in addition to ancillary services. The major disadvantage of this market model is that the cost of investing in energy production is far cheaper than investing in EES and that makes EE systems inefficient. Additionally, stakeholders also find it unfavorable if EES developers are allowed to operate as traditional energy generators and at the same time operate in a secluded environment to provide ancillary services, thereby getting two sources of revenue streams. The school of thought against this arrangement argues that such an arrangement can affect market efficiency.

130

Pumped Hydro Energy Storage for Hybrid Systems

Another scheme for revenue for PHES and for that matter EES is the rate-based model, where EES service providers are limited to revenue rate determined by the market regulator to recover investment cost. The major disadvantage of this market mechanism is that there is a high tendency to underutilize EES assets. However, it is a low-risk investment recovery model. The third approach to the EES market uses auctioning, which introduces a market that competitively auctions storage capacity rights to independent third parties that do not own the storage asset. The essence of the auction is to ration storage capacity between different potential uses, some of which may be priced in the market while others may be unpriced(rate-based). This scheme allows efficient use of assets.

8.4.4 Environmental barriers Pumped hydro energy storage projects require the permanent acquisition of sizeable lands. In the case of constructing an entirely new PHES plant with no lower or upper reservoir, a substantial size of the land is required. The PHES plant has the potential to also alter the ecosystem of the environment. Most often than not, several PHES projects face opposition from environmental organizations. Several PHES projects have seen undue delays or were eventually abandoned due to land litigation by environmental organizations (Yang & Jackson, 2011). Land acquisition challenges are seen as barriers towards the development of PHES. In the development of PHES, environmental difficulties such as land use, vegetation clearing, and land ownership are encountered, and thus hinder its development (Ali, Stewart, & Sahin, 2021). Sometimes PHES projects are stalled because of the challenges faced on the land proposed for the project. Some of these challenges include protected lands or forests, river systems, urban or rural settlements or intensive agriculture, national parks, or areas of historical or cultural value. These must be followed since doing otherwise violates environmental and social guidelines (Blakers, Lu, & Stocks, 2017). Biodiversity loss is seen as one of the major challenges of PHES projects as environmentalists do not compromise on this. Studies have shown that biodiversity loss associated with birds and fisheries, and temperature changes, and soil erosion has halted PHES developments. Environmental activists in the United States kicked against the Hudson River project because of the assertions that it posed a threat to the fisheries business (Yang & Jackson, 2011). Equally, a study in Turkey stopped a PHES

Techno-economic challenges of pumped hydro energy storage

131

construction site due to its sensitivity to biodiversity loss and requested to ensure the protection of critical habitats threatened (Kucukali, 2014). In Nepal, a study cautioned that river projects might pose a threat to fish migrations due to the disturbance of river ecology (Suhardiman & Karki, 2019).

8.4.5 Other barriers Pumped hydro storage systems face a lot of challenges in their utilization though they have seen many successes. The amount of time taken for the PHES to be commissioned as functional is not an easy task at all. PHES project developers face a regulatory timeline for the development of new projects. In the United States, for instance, any non-Federal pumped storage developer must obtain a Federal Energy Regulatory Commission (FERC) license, as well as multiple other state or federal permits. Under this FERC licensing process, obtaining a new project license to construct can take 3 to 5 years, or even longer before the developer will have the authority to begin project construction. Also, a 3- to 5-year construction period is common for most large projects; furthermore, environmentally kind projects, to support RE integration, could take 6 to 10 years or longer to construct. Very few financial institutions are willing to finance these types of long-lead projects through the licensing timeframe. This has been the situation in most countries around the world (NHA’s Pumped Storage Development Council, 2018).

8.5 The way forward The concept of PHES is well established and proven to be able to mitigate the intermittent nature of RE in the energy sector. However, it is faced with some technological, economic, social, and regulatory barriers to the deployment of PHES at various utility scales, which need a novel approach to curtail the challenges to enhance its deployment. A study conducted by Pali & Vadhera (2018) advanced how to use a well as a lower reservoir of the PHES system, while the upper reservoir needed for the water storage is made on the ground. The wind turbine, unlike other PHES schemes, is not used for rotating the electric generator at all, but to rotate the hydraulic pump, which is used to suck the water from the well and to store it in the upper reservoir. The water head created in this way is utilized to run a pico-hydro turbine coupled with a generator for generating electric power. The attractive features of the scheme are its low

132

Pumped Hydro Energy Storage for Hybrid Systems

cost, simplicity, reliability, and continuity in power supply at constant voltage, irrespective of wind speed variations. A study shows that wind energy with PHES is considered as the most suitable storage technology for allowing high wind penetration levels (Caralis, n.d.). Importance towards the deployment of PHES and the benefits accompanied are clear. Current market structures and regulatory frameworks, however, do not present an effective means of achieving this goal. Therefore, policy changes are desired to support the timely development of additional grid-scale energy storage. It is by this that the National Hydropower Association (2018) developed a series of recommendations to guide the energy industry and policymakers. NHA’s recommendations include: 1. Creating an enabling market for flexible resources to provide services that help meet electric grid requirements, including very fast responding systems that provide critical capacity during key energy need periods. 2. Creating a policy that allows flexibility for PSH with other storage technologies to inspire the growth and deployment of all energy storage technologies. 3. Recognize the role PHES plays in contributing to diversifying generation mix that includes intermittent renewable energies. 4. Recognize the energy security role PSH plays in the domestic electric grid. 5. Establish an alternative, streamlined licensing process for low-impact PSH, such as off-channel or closed-loop projects, to speed up the processes involved. 6. Facilitate an energy market structure where transmission providers benefit from long-term agreements with energy storage facility developers. Environmental impacts of hydropower plants and for that matter PHES cannot be overemphasized. This has been a reason why many schools of thought do not recognize large hydropower plants as renewal because of the damage they cause to the natural environment. To reduce or minimize the impact, a relatively new approach for developing pumped storage projects is to locate the reservoirs in areas that are physically separated from existing river systems. These approaches or designs are termed “closed-loop” pumped storage and they present minimal to no impact to existing river systems. The only additional water requirement is minimal operational make-up water required to offset evaporation or seepage losses after the initial filling of the reservoirs. The design has the potential to greatly reduce the most significant aquatic impacts associated

Techno-economic challenges of pumped hydro energy storage

133

with project development and because it is closed-loop pumped storage, it does not need to be located near an existing river system or body of water. The basic requirement is the right topographical features and can be located where needed to support the grid (NHA’s Pumped Storage Development Council, 2018). Another interesting way to increase PHES deployment is to fully optimize PHES in the day-ahead markets, considering real-time market-level optimization, if it is feasible. Doing this will allow scheduling the PHES more accurate. PHES loses opportunity costs based on multiple hours for ancillary service clearing prices and as such, a sub-hourly settlement compensation of PHES should be considered. To make the technology an attractive venture, PHES should be paid for its performance, and thus the ability to provide superior regulating reserves (fast response) and load balancing ability. A possible compensation system for voltage control also could be feasible (Táczi, 2016).

8.6 Conclusion This paper detailed the challenges facing the deployment of PHES systems. It looked at several technological/geographical, economic, and regulatory barriers to the utilization of PHES. With increased harnessing of RE sources like wind and solar, PHES plays an important role in the effective utilization of energy produced from such intermittent sources. Therefore, there is the need to address the barriers hindering the deployment of the technology. The paper has put together measures to undertake to curtail these challenges and to enhance its development.

References Aagreh, Y., & Al-Ghzawi, A. (2013). Feasibility of utilizing renewable energy systems for a small hotel in Ajloun city, Jordan. Applied Energy, 103, 25 31. Available from https://doi.org/10.1016/j.apenergy.2012.10.008. Abdellatif, D., AbdelHady, R., Ibrahim, A. M., El-Zahab, E. A., Schmidt, O., Melchior, S., . . . Struss, B. (2018). Which flexibility options facilitate the integration of intermittent renewable energy sources in electricity systems? Energy Conversion and Management, 5(1), 1 20. Available from https://doi.org/10.1016/B978-0-12-8036594.00004-7. Al-hadhrami, L. M., & Alam, M. (2015). Pumped hydro energy storage system : A technological review, 44, 586 598. Available from https://doi.org/10.1016/j.rser.2014.12.040. Ali, S., Stewart, R. A., & Sahin, O. (2021). Drivers and barriers to the deployment of pumped hydro energy storage applications: Systematic literature review. Cleaner

134

Pumped Hydro Energy Storage for Hybrid Systems

Engineering and Technology, 5, 100281. Available from https://doi.org/10.1016/j.clet. 2021.100281. Aswathanarayana, U. (2010). Hydropower. Green energy: Technology, economics and policy (pp. 39 43). Available from https://doi.org/10.1201/b10163. Barbour, E., Wilson, I. A. G., Radcliffe, J., Ding, Y., & Li, Y. (2016). A review of pumped hydro energy storage development in significant international electricity markets. Renewable and Sustainable Energy Reviews, 61, 421 432. Available from https:// doi.org/10.1016/j.rser.2016.04.019. Blakers, A., Lu, B., & Stocks, M. (2017). 100% renewable electricity in Australia. Energy, 133, 471 482. Available from https://doi.org/10.1016/j.energy.2017.05.168. Caralis, G. (n.d.). Hybrid systems (Wind with pumped storage). In International conference: RES & energy savings in Islands, Local Planning and European Cooperation. Cavazzini, G., Houdeline, J. B., Pavesi, G., Teller, O., & Ardizzon, G. (2018). Unstable behaviour of pump-turbines and its effects on power regulation capacity of pumped-hydro energy storage plants. Renewable and Sustainable Energy Reviews, 94 ( June), 399 409. Available from https://doi.org/10.1016/j.rser.2018.06.018. Driscoll, W. (2019, May). Pumped hydro with better financing can compete with batteries—pv magazine International. ,https://www.pv-magazine.com/2019/05/15/pumped-hydrowith-better-financing-can-compete-with-batteries/.. European Commission. (n.d.). DG ENER Working Paper The future role and challenges of energy storage. Electric Power Research Institute. (2010). Electricity energy storage technology options. Report 1020676, 170. ,http://www.epri.com/abstracts/Pages/ProductAbstract.aspx? ProductId 5 000000000001020676.. Environmental and Energy Study Institute. (2019). Fact sheet Energy storage (2019) White Papers EESI. ,https://www.eesi.org/papers/view/energy-storage-2019.. Hemmati, R., & Saboori, H. (2016). Emergence of hybrid energy storage systems in renewable energy and transport applications—A review. In Renewable and sustainable energy reviews. ,https://doi.org/10.1016/j.rser.2016.06.029.. Hino, T., Engineering, C. T. I., & Co, I. (2012). Pumped storage hydropower developments . Comprehensive renewable energy (6). Elsevier Ltd. Available from https://doi.org/10. 1016/B978-0-08-087872-0.00616-8. Javed, M. S., Zhong, D., Ma, T., Song, A., & Ahmed, S. (2020). Hybrid pumped hydro and battery storage for renewable energy based power supply system. Applied Energy, 257(October 2019), 114026. Available from https://doi.org/10.1016/j.apenergy.2019. 114026. King, A. (2015). Hydro power. Chemistry and Industry (London), 79(6), 42 45. Available from https://doi.org/10.1002/cind.796_14.x. Kucukali, S. (2014). Finding the most suitable existing hydropower reservoirs for the development of pumped-storage schemes: An integrated approach. Renewable and Sustainable Energy Reviews, 37, 502 508. Available from https://doi.org/10.1016/j. rser.2014.05.052. Ma, T., & Javed, M. S. (2019). Integrated sizing of hybrid PV-wind-battery system for remote island considering the saturation of each renewable energy resource. Energy Conversion and Management. Available from https://doi.org/10.1016/j.enconman.2018. 12.059. Ma, T., Yang, H., & Lu, L. (2014). Feasibility study and economic analysis of pumped hydro storage and battery storage for a renewable energy powered island. Energy Conversion and Management. Available from https://doi.org/10.1016/j.enconman.2013. 12.047. Mathiesen, B. V., Lund, H., Connolly, D., Wenzel, H., Ostergaard, P. A., Möller, B., . . . Hvelplund, F. K. (2015). Smart energy systems for coherent 100% renewable energy

Techno-economic challenges of pumped hydro energy storage

135

and transport solutions. Applied Energy, 145, 139 154. Available from https://doi. org/10.1016/j.apenergy.2015.01.075. Mckeogh, E. J., & Deane, J. P. (2010). Techno-economic review of existing and new pumped hydro energy storage plant, 14, 1293 1302. Available from https://doi.org/10.1016/j. rser.2009.11.015. Ming, Z., Kun, Z., & Daoxin, L. (2013). Overall review of pumped-hydro energy storage in China: Status quo, operation mechanism and policy barriers. Renewable and Sustainable Energy Reviews, 17, 35 43. Available from https://doi.org/10.1016/j.rser. Mongird, K., Viswanathan, V., Alam, J., Vartanian, C., Sprenkle, V., & Baxter, R. (2020). 2020 Grid energy storage technology cost and performance assessment. December, 117. ,https://www.pnnl.gov/sites/default/files/media/file/Final. ESGC Cost Performance Report 12-11-2020.pdf. NHA’s Pumped Storage Development Council. (2018). Challenges and opportunities for new pumped storage development. NREL. (2018). Market opportunities and challenges for pumped hydro in an evolving power grid preprint. August. Pali, B. S., & Vadhera, S. (2018). A novel pumped hydro-energy storage scheme with wind energy for power generation at constant voltage in rural areas. Renewable Energy, 127, 802 810. Available from https://doi.org/10.1016/j.renene.2018.05.028. Pearre, N. S., & Swan, L. G. (2015). Technoeconomic feasibility of grid storage: Mapping electrical services and energy storage technologies. Applied Energy. Available from https://doi.org/10.1016/j.apenergy.2014.04.050. Poulain, A., de Dreuzy, J. R., & Goderniaux, P. (2018). Pump hydro energy storage systems (PHES) in groundwater flooded quarries. Journal of Hydrology, 559(February), 1002 1012. Available from https://doi.org/10.1016/j.jhydrol.2018.02.025. Rangoni, B. (2012). A contribution on the regulation of electricity storage: The case of hydro-pumped storage in Italy and Spain. In International Conference on the European Energy Market (EEM), pp. 1 8. Sioshansi, R. (2017). Using storage-capacity rights to overcome the cost-recovery hurdle for energy storage. IEEE Transactions on Power Systems, 32(3), 2028 2040. Available from https://doi.org/10.1109/TPWRS.2016.2607153. Suhardiman, D., & Karki, E. (2019). Spatial politics and local alliances shaping Nepal hydropower. World Development, 122, 525 536. Available from https://doi.org/10. 1016/j.worlddev.2019.06.022. Táczi, I. (2016). Pumped storage hydroelectric power plants: Issues and applications. Ummels, B. C., Pelgrum, E., & Kling, W. L. (2008). Integration of large-scale wind power and use of energy storage in the Netherlands’ electricity supply. IET Renewable Power Genergy, 2, 34 46. Available from https://www.google.com/search?q 5 Ummels 1 BC%2C 1 Pelgrum 1 E.%2C 1 Kling 1 W.L.%3A 1 ‘Integration 1 of 1 large-scale 1 wind 1 power 1 and 1 use 1 of 1 energy 1 storage 1 in 1 the 1 Netherlands’ 1 electricity 1 supply’%2C 1 IET 1 Renew. 1 Power 1 Gener.%2C 1 2008%2C 1 2% 2C 1 pp. 1 34 46&rlz 5 1C1CHBF_enGH887GH8. Yang, C., & Jackson, R. B. (2011). Opportunities and barriers to pumped-hydro energy storage in the United States. Renewable and Sustainable Energy Reviews, 15(1), 839 844. Available from https://doi.org/10.1016/j.rser.2010.09.020.

This page intentionally left blank

CHAPTER 9

Lessons for pumped hydro energy storage systems uptake Martin Kyereh Domfeh1,2,3, Felix A. Diawuo1,4, Komlavi Akpoti1,5, Eric O. Antwi1,3 and Amos T. Kabo-bah1,2,3 1

Regional Centre for Energy and Environmental Sustainability (RCEES), UENR, Sunyani, Ghana Earth Observation Research and Innovation Center (EORIC), UENR, Sunyani, Ghana Department of Civil and Environmental Engineering, School of Engineering, UENR, Sunyani, Ghana 4 School of Energy, UENR, Sunyani, Ghana 5 International Water Management Institute (IWMI), Accra, Ghana 2 3

Contents 9.1 9.2 9.3 9.4 9.5

Introduction Classifications of pumped hydro energy storage Site considerations for pumped hydro energy storage development Climate change impact on pumped hydro energy storage Drivers and barriers to pumped hydro energy storage 9.5.1 Classification of pumped hydro energy storage drivers 9.5.2 Classification of pumped hydro energy storage barriers 9.6 Market overview and future trends of pumped hydro energy storage 9.6.1 Financial and economic assessment indices of pumped hydro energy storage projects 9.6.2 Pumped hydro energy storage financing models 9.7 Key factors for pumped hydro energy storage uptake 9.7.1 Investing in public-private research, development and deployment 9.7.2 Instituting regulatory frameworks that stimulate innovative operation of pumped hydro energy storage 9.7.3 Increasing digital operation of pumped hydro energy storage systems 9.7.4 Retrofitting pumped hydro energy storage facilities 9.8 Conclusion References

137 139 140 141 141 141 144 148 148 149 149 149 150 150 151 151 151

9.1 Introduction The upscaling of energy storage systems (ESS) has become crucial in recent years, primarily due to the increasing interest in renewable energy (RE) and energy systems decarbonization as a result of climate Pumped Hydro Energy Storage for Hybrid Systems DOI: https://doi.org/10.1016/B978-0-12-818853-8.00012-1

© 2023 Elsevier Inc. All rights reserved.

137

138

Pumped Hydro Energy Storage for Hybrid Systems

change and its impacts. Some renewable and clean energy sources such as solar and wind are intermittent and so cannot deliver nameplate and continuous power capacity. The wind is a very changeable meteorological component that changes hourly, daily, weekly, monthly, and annually. Radiation from the sun, on the other hand, is less changeable yet only operates during the day. The variable and intermittent nature of these renewables tend to introduce a wave of challenges such as grid system instability and irregular power supply. ESS are therefore needed to link these RE technologies to the grid to deliver continuous and high-quality power. Well-known ESS in the electricity generation portfolio include compressed air energy storage, hydrogen storage systems, lead batteries, flywheels, supercapacitors, and others. But among these ESS options, pumped hydro energy storage (PHES) is recognized as the most promising technology for managing large energy networks. PHES consists of two interconnected reservoirs at different altitudes. It stores energy by pumping water from a lower to an upper reservoir tank during a period of low electricity demand when electricity prices are low (Hino & Lejeune, 2012). During the peak demand period, water stored at the upper reservoir tank is then released through the hydraulic turbines to generate electrical power (IRENA, 2020a). This implies that the operation of PHES requires the provision of a pump and generator to be situated between the two reservoirs (Kocaman & Modi, 2017). Globally, PHES potential is estimated to be 23 3 106 GWh in over 600,000 plants (Lu, Stocks, Blakers, & Anderson, 2018). PHES is recognized as the most matured and utility-sized energy storage technology for addressing peak load demands in the electricity market (Díaz-González, Sumper, & Gomis-Bellmunt, 2016). Also being a clean source of energy, it contributes little to the carbon footprint in addition to providing an opportunity for the optimal use of water, energy, and land resources in both the short and long terms. In addition, it has an immediate start-up time which enables it to rapidly respond to varying energy demands. PHES also has a relatively lower capital cost per kWh of energy storage and usually has a longer lifespan. According to Barbour, Wilson, Radcliffe, Ding, and Li (2016) and IHA (2020), PHES provides the following enormous ancillary services and advantages: 1. flexible start/stop and quick reaction time 2. capacity to watch load changes and adjust to dramatic load fluctuations 3. ability to vary the frequency while maintaining voltage stability

Lessons for pumped hydro energy storage systems uptake

139

facilitating the increased deployment of low-carbon generation increasing reliability for end users facilitating a time of use energy management increasing system flexibility reducing the volatility of electricity prices reducing the need for transmission upgrades/new transmission infrastructure reducing overall pollutant emissions. Notwithstanding these enormous advantages, PHES is often criticized as having relatively lower energy density as compared with some other ESS, higher construction cost and longer construction time compared to other energy generation plants, destruction or disruption of aquatic and terrestrial habitats as a result of the impoundment of water, etc. 4. 5. 6. 7. 8. 9. 10.

9.2 Classifications of pumped hydro energy storage ˇ ceki´c, Mujovi´c, and Radulovi´c (2020) and IRENA (2012), According to S´ there are conventionally two main classifications of PHES (see Fig. 9.1): 1. Conventional river-based or open-loop PHES: Possesses two interconnected reservoirs at different elevations where the lower reservoir continuously receives its inflows from a river inflow. This continuous supply of river inflows provides additional flexibility to the scheme.

Figure 9.1 Configuration schemes for pumped hydro energy storage and renewables (IRENA, 2020a).

140

Pumped Hydro Energy Storage for Hybrid Systems

2. Off-river PHES or closed-loop PHES: Though also composed of two interconnected reservoirs, the system does not receive any river inflows. The absence of a river inflow minimizes flood mitigation costs, ensures higher heads, eliminates the negative impacts of damming, and ensures speedy construction. At present, PHES systems are being coupled with other forms of variable RE systems based on a variety of hybrid PHES designs for both grid and off-grid applications, and these include wind-PHES hybrid system (Pali & Vadhera, 2018), hybrid wind-solar-PHES-battery system (Javed, Zhong, Ma, Song, & Ahmed, 2020), hybrid solar-wind-PHES-diesel generator system (Kusakana, 2016), integrated fossil fuel-wind-PHES system (Segurado, Madeira, Costa, Dui´c, & Carvalho, 2016), and double storage PHES-battery powered by renewable energy sources (RES) (Abdelshafy, Jurasz, Hassan, & Mohamed, 2020).

9.3 Site considerations for pumped hydro energy storage development To ensure optimal harnessing of the economic, social, and environmental benefits of a PHES project, there is the need for the careful selection of an appropriate site for the project. Key among the site considerations for PHES development is the availability of a suitable geographical location with a desirable head and the availability of water (Kocaman & Modi, 2017). Economic factors considered during site consideration for a PHES project include nearness to power lines, access to a road network, geological condition of the site, head-distance ratio, the complexity of the civil works involved, as well as seismic considerations. On the social aspects, the following factors are taken into consideration: nearness to an urban area, settlement, potential for a new latent fault, as well as land use. Alteration to either the daily water level or the water flow rate or both, sealed ground surface, local solar irradiation, and wind speed in addition to landcover form part of a group of environmental factors considered during the site selection process (Nzotcha, Kenfack, & Blanche Manjia, 2019). Due to the complexity of the multiple social, techno-economic, and environmental factors considered during the site selection of PHES, a multi-criteria decision-making (MCDA) tool is often used. A typical MCDA for PHES site selection encompasses three (3) main stages: (1) defining the problem, (2) decision-making, and (3) recommendation.

Lessons for pumped hydro energy storage systems uptake

141

9.4 Climate change impact on pumped hydro energy storage PHES projects are impacted by climate change through the modification of rainfall patterns, water availability, and significant variation in temperature regimes. Though PHES is known to have a long project lifespan, this on the other hand also exposes its operations to the severe impact of climatic and hydrological uncertainties. Particularly, small-scale hydropower projects, in general, appear to be more vulnerable to climate change impacts. However, PHES is generally less vulnerable, due to its efficient capture and re-use of stored water, which offers added flexibility to the system. Thus, there is an urgent need to consciously integrate climate adaptation, mitigation, and risk assessment into the design and planning of PHES.

9.5 Drivers and barriers to pumped hydro energy storage The drivers and barriers associated with PHES can be categorized broadly into socio-economic and techno-environmental factors. The socio-economic factors look at both the positive and negative influence of the deployment of PHES on social and economic dimensions, for example, resettlement issues, job opportunities, revenue mobilization, etc. The techno-environmental factors also look at both the positive and negative impact of the utilization of PHES on technical and environmental dimensions, for example, land use, topography, clearing of vegetation, clean energy, etc. (Ali, Stewart, & Sahin, 2021).

9.5.1 Classification of pumped hydro energy storage drivers 9.5.1.1 Socio-economic drivers Energy arbitrage: This technique works by pumping water to the upper reservoir during off-peak periods where electricity prices are low and then turbining at peak demand hours where electricity prices are high. The opportunities associated with energy arbitrage trading, therefore, appeal to investors to invest in this technology. Due to technological advancement, the cost of generating electricity from renewables has been reducing over the years and these sources are opinionated to be competitive and even cheaper than fossil fuels (Ram et al., 2018). This is indeed true for PHES whose capital costs remain high, but its low cost in running and

142

Pumped Hydro Energy Storage for Hybrid Systems

maintenance makes it commercially lucrative in the long run while delivering low-cost electricity. Rural development: Various job and business opportunities are often created for the local inhabitants during the construction and operation phase of PHES projects, especially in developing countries. Commercial opportunities such as fish farming, tourism and recreational activities, property rentals around the project site, etc., serve as a critical societal motivator for rural development. Further, local contractors may be adequately rewarded for delivering materials and other critical services during the construction process. Since large PHES are usually located in isolated places that lack basic and essential amenities such as hospitals, roads, schools, and infrastructure, PHES development naturally delivers such facilities in addition to revenue sharing and local tax payment which enhance the socioeconomic development of the rural inhabitants (Ali et al., 2021). 9.5.1.2 Techno-environmental drivers Utility-scale storage: PHES could be used in power networks for daily and seasonal storage of renewable and non-RE to address fluctuation in the power system since it provides flexibility to seasonal variations and is easy to dispatch (Kear & Chapman, 2013). For intra-day balancing, excess power from baseload technologies such as nuclear and coal is mostly used for pumping water to the upper reservoir at night and is used to enhance required generation during peak demand periods. Some PHES, on the other hand, maybe used as weekly or monthly storage if it is economically justified. Overall, both daily and seasonal storage choices for utility-scale applications are driving forces behind global PHES growth (Ali et al., 2021). Grid resilience: The progress of PHES is crucial to the present power networks as it supports the transition to RE systems (Ghorbani, Makian, & Breyer, 2019). By distributing electricity when demand is high and storing it when supply is high, PHES can provide energy time-shifting and grid balancing of variable RE sources. Additionally, as shown in Fig. 9.2, PHES provides auxiliary support like frequency and voltage modulation, detection and response to high load variations, reduction of renewables curtailment, capacity firming, fast and flexible ramping, and black start to relieve grid congestions. Due to its extraordinary operational mobility, PHES is frequently used as a backup powerhouse, quickly regulating unanticipated changes caused by either demand or generation. PHES can move from zero to full power in minutes, which is crucial for

Lessons for pumped hydro energy storage systems uptake

143

Figure 9.2 Contribution of pumped hydro energy storage to the power sector (IRENA, 2020a).

averting system-wide mishaps and recovering from disasters and catastrophes. In addition to their role in local grids, PHES plays a significant supplementary role in regional grids and cross-regional interconnected grids (Ali et al., 2021). Sustainability: The development and utilization of PHES enhance the penetration of RE and directly lower reliance on non-RE sources such as coal power. Furthermore, substituting these high carbon sources with PHES integrated with renewable sources can substantially reduce anthropogenic emissions such as carbon monoxide, nitrogen oxides, sulfides, particulates, etc (Ming et al., 2013). Carbon dioxide (CO2) is the major contributor to greenhouse gases, which causes global warming. As a result, implementing PHES and cutting CO2 emissions entails attaining lowcarbon economic development while also implementing the Paris Climate Agreement. PHES has a life expectancy of 40 to 80 years, with some studies estimating a life expectancy of up to 100 years (Deane, Ó Gallachóir, & McKeogh, 2010), meaning that it is a dependable and onetime investment that is attractive to investors and governments searching for commercial prospects. Auxiliary services: A few of the auxiliary services linked with PHES include sediment and flood control, breeding sites for amphibians, groundwater recharge and replenishment, etc. PHES can reduce floods and silt that normally occur as a result of natural land degradation and the establishment of settlements upstream. This is because the reservoir holds

144

Pumped Hydro Energy Storage for Hybrid Systems

water to decrease the impact of floods and sediments and prevent them from reaching vulnerable downstream settlements (Munthali, Irvine, & Murayama, 2011). Further, a comprehensive PHES system may support the existence of amphibians and water-related insects and it can also positively influence the microclimate and enhance the landscape. PHES could be good for the environment since it allows for groundwater recharge and replenishment, which is an important step in sustainable groundwater management (Ali et al., 2021).

9.5.2 Classification of pumped hydro energy storage barriers 9.5.2.1 Socio-economic barriers The socio-economic barriers capture key factors such as public opposition, market failures, institutional challenges and political interference, project investment and financing, etc. Public opposition: Public disputes, arguments and not in my backyard (NIMBY) syndrome are usually common with the development of PHES and hydro projects. There is usually a notion of breeding mosquitos which causes diseases, bad smell, and risk of explosion when earthquakes occur. The issues of potential dispersion of existing communal values, habitat, and livelihood due to resettlement or relocation of local people also create opposition. Further, the potential disturbance to the fishing population and other linked benefits for downstream settlers are major factors for public outcry in hydro developments. At times lack of information on financial and ecological benefits also creates this dispute, which can create delays in the approval and construction of these projects (Ali et al., 2021). Market failures: This could include market rule unpredictabilities, scarcity of skilled labor, state-controlled energy industry, and others (Ali et al., 2021). The availability of skilled labor like technicians, engineers, policy experts, etc. is needed for hydro development and their availability locally is mostly governed by the country’s educational system. Due to the grappling economy, developing countries usually lack local specialists who can do feasibility studies or aid in the construction of hydro projects. Hiring the services of expatriates could increase the entire project cost due to their expensive salaries and incentives. The liberalization of electricity markets accelerates the development of PHES projects, whilst failure to do so has negative implications (Deane et al., 2010). Uncertain market regulations are a major reason for limited project investment; hence this is also seen as a barrier.

Lessons for pumped hydro energy storage systems uptake

145

Furthermore, the usual operation of a PHES project is for the plant to operate during a short period to meet the peak energy demand. Thus, in the implementation of a PHES project, special attention must be paid to the prevailing market pricing and regulations scheme to ensure value for money (Abdellatif, AbdelHady, Ibrahim, & El-Zahab, 2018). The following are the major market infrastructures under which a typical PHES may operate: Liberalized: Also known as a “deregulated” market, this type of market infrastructure promotes competition and reduces price hikes by opening its avenue to all prospective energy service providers (Dragoon, 2010; Esmaeili Aliabadi, Çelebi, Elhüseyni, & S¸ ahin, 2021). Regional monopoly: This option of market infrastructure makes provision for each region to be served by a sole utility firm while all the regions remain interconnected (Shen & Yang, 2012). Regional monopoly open to independent power producers (IPPs): This type of market infrastructure is synonymous with the Regional Monopoly only that IPPs are allowed to take part in the provision of energy services (Shen & Yang, 2012). National monopoly: Under this category, a sole state-owned utility company is put in charge of the generation, transmission, distribution, and retail of energy services to consumers (Shen & Yang, 2012). According to Barbour et al. (2016), more than 95% of PHES plants investigated in their study were commissioned under the three categories of monopoly market structures: national, regional, and regional monopoly that is open to IPPs. Also, a detailed survey of available literature revealed that the liberalized market environment generally provides a congenial atmosphere for the growth of PHES. However, it may reduce the prices of electricity and hence the returns on PHES investment. In the nutshell, the need for robust, transparent, as well as detailed market regulations without any ambiguity is crucial for the sustainability of a PHES under any market scheme or infrastructure. Institutional challenges and political interference: Corruption, lack of proper institutional coordination, and legal frameworks could be major barriers to the development of PHES. The delays and bureaucracy associated with appropriate authorities granting licenses to potential developers can aggravate this issue while dissipating social resources. Project investment and financing: The extent of capital and operational expenditure, payback length, and other economic factors could create barriers to PHES development. The capital expenditure for PHES projects is frequently site-specific, with some studies predicting a h600 3000/kW

146

Pumped Hydro Energy Storage for Hybrid Systems

range (Deane et al., 2010) and there could be an additional cost in securing financing for all capital costs. The costs of operating and maintaining the facility, as well as pumping water to the upper reservoir, may be included in the costs of operation and maintenance (Ali et al., 2021). This cost, of course, may vary depending on the specific time electricity is borrowed from the grid to power the pumping equipment. Furthermore, open-loop PHES plants that draw water from a river or lake may attract a water usage tax. Wages and compensation for employees are among the other expenses. Additional costs would be paid to compensate businesses in the flooded public downstream including the agriculture and fishing sectors. Another hurdle to the growth of PHES is the payback period needed to repay loans, which is predicted to be at least 2.5 5.5 years (Connolly, MacLaughlin, & Leahy, 2010). The development of a new PHES is dependent on the availability of funds from sources such as the government, Multilateral Development Banks (MDBs), private developers or mixed funding sources, and usually, this could be a daunting and complex process. At times, due to the long payback duration and licensing time unpredictabilities, not many organizations or private investors are willing to support such long-term ventures (Ali et al., 2021). According to studies, the public sector now funds the vast majority of PHES systems in existence, which is unsustainable in the long-term financing of PHES projects. 9.5.2.2 Techno-environmental barriers The techno-environmental barriers capture key factors such as biodiversity loss, water issues, land acquisition challenges, landscape topology, lack of infrastructure support, etc. Biodiversity loss: Depending on the nature of the site for construction, PHES has the potential of causing serious environmental impediments including perceived effects of climate change on fisheries and birds, as well as temperature changes, and soil erosion. Water issues: This could be a major hindrance to the development of PHES and may take any of the following forms: water availability and quality issues, water loss, oxygen loss, conflict of interest with local water supply, especially for open-loop PHES systems, and other hydrological issues such as huge water volumes needed to fill up the reservoir. The development of PHES could have less potential in countries where water scarcity is more common, such as Jordan, Iran, Cameroon, etc. (Droogers et al., 2012). Another source of worry is leakage and water evaporation

Lessons for pumped hydro energy storage systems uptake

147

loss, which is mitigated to some extent by rainfall and occasional water replenishment. A group of environmental activists in Hudson Highlands in the United States prevented the development of a PHES project that posed a danger to the local water supply (Yang & Jackson, 2011). Water oxygen loss has also been observed in a hydro station in South Carolina, United States, where a system for oxygen injection was installed to resolve the challenge (Ali et al., 2021). Land acquisition challenges: Site acquisition challenges comprise issues of land ownership, land use, vegetation clearing, etc. which are inherent in some of the environmental challenges of PHES. Disruption to forests, rivers, protected lands, historically or culturally significant areas, etc. should be avoided. Infringement of these principles is typically in contrast to the environmental and social viewpoint, which ultimately impedes PHES development. Land ownership is a major barrier as locals may claim ownership of empty areas, or purposefully migrate into planned project areas by erecting temporary structures before construction begins in order to receive compensation money (Ali et al., 2021). Landscape topology: Site topology determines the type, slope and shape of the dam, elevation, head to length (H/L) ratios, and the amount of earthwork needed to construct the PHES. Usually, a high head indicates less needed construction and relatively lower equipment costs. The time and cost of cutting and filling the surface when establishing an artificial reservoir are reduced with a mild slope surface. Sites with more than a 10% slope, for instance, are a stumbling barrier. The H/L ratio is the gross head divided by the horizontal distance between the two reservoirs of a PHES, and it is generally 10/2 for most PHES projects (Ali et al., 2021). A greater H/L ratio suggests more hydraulic losses and higher excavation and building costs, hence landscape topology affects both the economic and technical aspects of PHES projects. A H/L of 10/2 is generally used for most PHES projects (Ali et al., 2021). Lack of infrastructure support: The nonexistence of transmission lines and access roads creates both technical and financial impediments to the development of PHES. This is because having a road and electrical transmission system nearby is beneficial as it allows for easy access to the materials supply required during the construction and maintenance stages; without this infrastructure, creating new highways would increase the project’s initial cost. Again, to transmit power, it must be connected to adjacent transmission lines or a power utility grid. When there is excess electricity in a grid, it can be used to pump water, and when power is needed for load

148

Pumped Hydro Energy Storage for Hybrid Systems

balance, generation can be done by using the stored water. However, the plant in certain instances can be rendered unusable due to a shortage of surplus power, especially if electricity for pumping is available during midnight and early morning (Ali et al., 2021). Notwithstanding these environmental impacts and concerns, modern PHES projects are being designed and implemented to address these challenges through the use of new approaches and technologies such as the use of off-stream systems, abandoned quarries, and mines, underground reservoirs, and groundwater systems in addition to the proposed use of wastewater for off-stream PHES projects (Yang & Jackson, 2011).

9.6 Market overview and future trends of pumped hydro energy storage Presently, over 340 PHES projects have been implemented globally and across over 14 countries with China, the United States, and Japan having the largest capacities (Vasudevan, Ramachandaramurthy, Venugopal, Ekanayake, & Tiong, 2021). Though many countries and regions such as the EU, China, and the United States are igniting initiatives toward expanding the PHES capacity, very little can be said about this in the African continent where it appears that only South Africa and Morocco have shown interest in PHES though RE projects on the African continent are continuously increasing. As a result of the growing need to increase the world’s energy storage capacity, the PHES market is expected to see a compound annual growth rate of more than 2% from 2020 to 2025 (Modor Intelligence, 2021). In most regions and countries such as China, Asia Pacific, the United States, Australia, and Europe, the drive towards deployment of more PHES is being fueled by governmental policies aimed at minimizing variable renewable energy (VRE) curtailment (IEA, 2021).

9.6.1 Financial and economic assessment indices of pumped hydro energy storage projects Various financial and economic indices are used in assessing PHES projects and these include the net present cost, net present value, levelized cost of energy or electricity, pay back period, internal rate of return, avoided cost of energy, benefit cost ratio, etc. These metrics in most instances determine the viability of any PHES project, especially at the project inception and selection stages where

Lessons for pumped hydro energy storage systems uptake

149

cost-effective tools and techniques are often used in selecting a project from several available alternatives (Gupta, Bhattacharya, Barabady, & Kumar, 2013). After the selection of an appropriate PHES, several installation cost components will be encountered in the implementation and these include costs related to the following: storage-balance of system, power equipment, controls & communication, Grid Integration, Engineering, Procurement, and Construction (EPC), and Project Development (IRENA, 2020b). There is also the need to take into account the cost associated with the operation and decommissioning of the project.

9.6.2 Pumped hydro energy storage financing models A detailed overview of factors that influence PHES project financing has been discussed by Head (2008), whereas a PHES project finance structure was also presented by (IHA, 2017b). In summary, a typical PHES project may be financed through any of the following models: EPC, build operate transfer, design-build-operate, finance, engineer, lease, and transfer, and climate financing (Eberhard, Gratwick, Morella, & Antmann, 2016; Marquard & Bahls, 2021; World Bank Group, 2020).

9.7 Key factors for pumped hydro energy storage uptake Considering some of the constraints and challenges linked to the smooth operation of PHES, certain key factors presented in Fig. 9.3 are required to motivate the deployment of PHES projects, especially in combination with other VRE sources and these include the following:

9.7.1 Investing in public-private research, development and deployment To fully harness the full potential and benefits associated with PHES combined with VRE and/or batteries, there will be the need for a massive investment of resources into Research, Development and Deployment (RD&D). This initiative will go a long way to minimize the associated project risk in addition to maximizing the investors’ confidence in PHES projects. Furthermore, a key ingredient for the success of this initiative will be a well-coordinated partnership between the public and the private sector (IRENA, 2020a).

150

Pumped Hydro Energy Storage for Hybrid Systems

Figure 9.3 Key factors to stimulate pumped hydro energy storage uptake (IRENA, 2020a).

9.7.2 Instituting regulatory frameworks that stimulate innovative operation of pumped hydro energy storage Since PHES plants are often used to complement VRE as well as other inflexible generation plants, there is the need to ensure the provision of a conducive market and regulatory climate that fosters innovation as well as inverter confidence in supporting and investing in PHES projects. These provisions could be channeled through any of the following means: provision of ancillary services, energy arbitrage, and capacity payments among others (IRENA, 2020a).

9.7.3 Increasing digital operation of pumped hydro energy storage systems Most innovative and optimization interventions in PHES are being driven by the rapid digitization of the operations of PHES. These digitization breakthroughs include power generation prediction using machine learning, remote equipment, monitoring, predictive maintenance, and smart coupling with batteries or with VRE plants (IHA, 2017a; IRENA, 2020a). Digital operation improves efficiency while reducing operational and maintenance costs since it could incorporate and support activities and applications such as virtual reality training for staff, maintenance robots, remote control maintenance technologies, etc (IRENA, 2020a).

Lessons for pumped hydro energy storage systems uptake

151

9.7.4 Retrofitting pumped hydro energy storage facilities One of the main strategies used to enhance system operations and maximize the benefits of PHES is by retrofitting the system with modernized and innovative components. Such state-of-the-art components and interventions may include the use of variable speed turbines to enhance response time and widen the operational range, thus maximizing economic returns. Also, the combination of existing PHES with other VRE systems such as floating PV minimizes capital expenditure costs (IRENA, 2020a).

9.8 Conclusion The global transition to more RE sources implies that flexible ESS such as PHES is crucial in the energy generation mix to address the intermittent and variable nature of the VRE sources. This flexible energy storage provision offered by PHES occurs at a relatively low cost and within an appreciably longer term compared to other energy storage solutions. Factors that motivate the deployment of PHES projects may include investing in Public-Private RD&D, instituting regulatory frameworks that stimulate innovative operation of PHES, increasing digital operation of PHES systems, and retrofitting PHES facilities. The liberalized market environment has been found to generally provide a congenial atmosphere for the growth of PHES. However, it may reduce the prices of electricity and hence the returns on PHES investment. There is therefore the need for robust, transparent, as well as detailed market regulations, without any ambiguity for the sustainability of a PHES under any market scheme or infrastructure.

References Abdellatif, D., AbdelHady, R., Ibrahim, A. M., & El-Zahab, E. A. (2018). Conditions for economic competitiveness of pumped storage hydroelectric power plants in Egypt. Renewables: Wind, Water, and Solar, 5(1), 1 14. Available from https://doi.org/ 10.1186/S40807-018-0048-1. Abdelshafy, A. M., Jurasz, J., Hassan, H., & Mohamed, A. M. (2020). Optimized energy management strategy for grid connected double storage (pumped storage-battery) system powered by renewable energy resources. Energy, 192. Available from https://doi. org/10.1016/J.ENERGY.2019.116615. Ali, S., Stewart, R. A., & Sahin, O. (2021). Drivers and barriers to the deployment of pumped hydro energy storage applications: Systematic literature review. Cleaner Engineering and Technology, 5, 2666 7908. Available from https://doi.org/10.1016/j. clet.2021.100281.

152

Pumped Hydro Energy Storage for Hybrid Systems

Barbour, E., Wilson, I. A. G., Radcliffe, J., Ding, Y., & Li, Y. (2016). A review of pumped hydro energy storage development in significant international electricity markets. Renewable and Sustainable Energy Reviews, 61, 421 432. Available from https:// doi.org/10.1016/j.rser.2016.04.019. Connolly, D., MacLaughlin, S., & Leahy, M. (2010). Development of a computer program to locate potential sites for pumped hydroelectric energy storage. Energy, 35(1), 375 381. Available from https://doi.org/10.1016/J.ENERGY.2009.10.004. Deane, J. P., Ó Gallachóir, B. P., & McKeogh, E. J. (2010). Techno-economic review of existing and new pumped hydro energy storage plant. Renewable and Sustainable Energy Reviews, 14(4), 1293 1302. Available from https://doi.org/10.1016/j. rser.2009.11.015. Díaz-González, F., Sumper, A., & Gomis-Bellmunt, O. (2016). Energy storage in power systems. John Wiley & Sons Ltd. Dragoon, K. (2010). Enhancing wind energy value. Valuing wind generation on integrated power systems. Elsevier Inc. Droogers, P., Immerzeel, W. W., Terink, W., Hoogeveen, J., Bierkens, M. F. P., Van Beek, L. P. H., & Debele, B. (2012). Water resources trends in middle East and North Africa towards 2050. Hydrology and Earth System Sciences, 16(9), 3101 3114. Available from https://doi.org/10.5194/HESS-16-3101-2012. Eberhard, A., Gratwick, K., Morella, E., & Antmann, P. (2016). Independent power projects in Sub-Saharan Africa—Lessons from five key countries. ,https://www.worldbank.org/ en/topic/energy/publication/independent-power-projects-in-sub-saharan-africa.. Esmaeili Aliabadi, D., Çelebi, E., Elhüseyni, M., & S¸ ahin, G. (2021). Modeling, simulation, and decision support. Local electricity markets (pp. 177 197). Academic Press. Available from https://doi.org/10.1016/B978-0-12-820074-2.00017-4. Ghorbani, N., Makian, H., & Breyer, C. (2019). A GIS-based method to identify potential sites for pumped hydro energy storage—Case of Iran. Energy, 169, 854 867. Available from https://doi.org/10.1016/J.ENERGY.2018.12.073. Gupta, S., Bhattacharya, J., Barabady, J., & Kumar, U. (2013). Cost-effective importance measure: A new approach for resource prioritization in a production plant. International Journal of Quality and Reliability Management, 30(4), 379 386. Available from https://doi.org/10.1108/02656711311308376. Head, C. (2008). The financing package. Hydro Finance Handbook,(prepared by the authors as a companion document for “Hydro Finance Tutorial,” Session 1C of the New Development Track of the HydroVision 2008 Conference). Kansas City, MO: HCI Publications. Hino, T., & Lejeune, A. (2012). Pumped storage hydropower developments. Comprehensive Renewable Energy, 6, 405 434. Available from https://doi.org/10.1016/ B978-0-08-087872-0.00616-8. IEA. (2021). Hydropower special market report. In Hydropower special market report. Available from https://doi.org/10.1787/07a7bac8-en. IHA. (2017a). 2017 Key trends in hydropower. ,https://www.hydropower.org/publications/2017-key-trends-in-hydropower.. IHA. (2017b). Hydropower financing. Asia clean energy forum deep-dive workshop, 5 8 June. IHA. (2020). 2020 Hydropower status report. ,https://www.hydropower.org/publications/ 2020-hydropower-status-report.. IRENA. (2012). Renewable energy technologies: Cost analysis series. Hydropower Power Sector. In Report No. 1(3/5). https://www.irena.org/documentdown-%0Aloads/publications/re_technologies_cost_analysis-hydropower.pdf. IRENA. (2020a). Innovation landscape brief: Innovative operation of pumped hydropower storage. ,http://www.irena.org.. IRENA. (2020b). Renewable power generation costs in 2019. ,https://www.irena.org/publications/2020/Jun/Renewable-Power-Costs-in-2019..

Lessons for pumped hydro energy storage systems uptake

153

Javed, M. S., Zhong, D., Ma, T., Song, A., & Ahmed, S. (2020). Hybrid pumped hydro and battery storage for renewable energy based power supply system. Applied Energy, 257, 114026. Available from https://doi.org/10.1016/J.APENERGY.2019.114026. Kear, G., & Chapman, R. (2013). “Reserving judgement”: Perceptions of pumped hydro and utility-scale batteries for electricity storage and reserve generation in New Zealand. Renewable Energy, 57, 249 261. Available from https://doi.org/10.1016/J. RENENE.2013.01.015. Kocaman, A. S., & Modi, V. (2017). Value of pumped hydro storage in a hybrid energy generation and allocation system. Applied Energy, 205, 1202 1215. Available from https://doi.org/10.1016/J.APENERGY.2017.08.129. Kusakana, K. (2016). Optimal scheduling for distributed hybrid system with pumped hydro storage. Energy Conversion and Management, 111, 253 260. Available from https://doi.org/10.1016/J.ENCONMAN.2015.12.081. Lu, B., Stocks, M., Blakers, A., & Anderson, K. (2018). Geographic information system algorithms to locate prospective sites for pumped hydro energy storage. Applied Energy, 222, 300 312. Available from https://doi.org/10.1016/J.APENERGY. 2018.03.177. Marquard & Bahls AG. (2021). EPC (Engineering, procurement and construction). Ming, Z., Junjie, F., Song, X., Zhijie, W., Xiaoli, Z., & Yuejin, W. (2013). Development of China’s pumped storage plant and related policy analysis. Energy Policy, 61, 104 113. Available from https://doi.org/10.1016/J.ENPOL.2013.06.061. Modor Intelligence. (2021). Pumped hydro storage market | 2022 27 | Industry share, size, growth—Mordor intelligence. ,https://www.mordorintelligence.com/industry-reports/ pumped-hydro-storage-market.. Munthali, K. G., Irvine, B. J., & Murayama, Y. (2011). Reservoir sedimentation and flood control: Using a geographical information system to estimate sediment yield of the Songwe River watershed in Malawi. Sustainability, 3(1), 254 269. Available from https://doi.org/10.3390/SU3010254. Nzotcha, U., Kenfack, J., & Blanche Manjia, M. (2019). Integrated multi-criteria decision making methodology for pumped hydro-energy storage plant site selection from a sustainable development perspective with an application. Renewable and Sustainable Energy Reviews, 112, 930 947. Available from https://doi.org/10.1016/J. RSER.2019.06.035. Pali, B. S., & Vadhera, S. (2018). A novel pumped hydro-energy storage scheme with wind energy for power generation at constant voltage in rural areas. Renewable Energy, 127, 802 810. Available from https://doi.org/10.1016/J.RENENE.2018.05.028. Ram, M., Child, M., Aghahosseini, A., Bogdanov, D., Lohrmann, A., & Breyer, C. (2018). A comparative analysis of electricity generation costs from renewable, fossil fuel and nuclear sources in G20 countries for the period 2015 2030. Journal of Cleaner Production, 199, 687 704. Available from https://doi.org/10.1016/J. JCLEPRO.2018.07.159. ˇ ceki´c, L., Mujovi´c, S., & Radulovi´c, V. (2020). Pumped hydroelectric energy storage as S´ a facilitator of renewable energy in liberalized electricity market. Energies, 13(22), 6076. Available from https://doi.org/10.3390/EN13226076. Segurado, R., Madeira, J. F. A., Costa, M., Dui´c, N., & Carvalho, M. G. (2016). Optimization of a wind powered desalination and pumped hydro storage system. Applied Energy, 177, 487 499. Available from https://doi.org/10.1016/J. APENERGY.2016.05.125. Shen, D., & Yang, Q. (2012). Electricity market regulatory reform and competition— Case study of the New Zealand electricity market. In Y. Wu, X. Shi, & F. Kimura (Eds.), Energy market integration in East Asia: Theories, electricity sector and subsidies

154

Pumped Hydro Energy Storage for Hybrid Systems

(Issue August (pp. 103 139). Jakarta: ERIA. Available from http://www.eria.org/ Chapter6-Electricity, Market Regulatory Reform and Competition-Case Study of the New Zealand Electricity Market.pdf. Vasudevan, K. R., Ramachandaramurthy, V. K., Venugopal, G., Ekanayake, J. B., & Tiong, S. K. (2021). Variable speed pumped hydro storage: A review of converters, controls and energy management strategies. Renewable and Sustainable Energy Reviews, 135, 110156. Available from https://doi.org/10.1016/J.RSER.2020.110156. World Bank Group. (2020). Concessions build-operate-transfer (BOT) and design-build- operate (DBO) projects. Yang, C. J., & Jackson, R. B. (2011). Opportunities and barriers to pumped-hydro energy storage in the United States. Renewable and Sustainable Energy Reviews, 15(1), 839 844. Available from https://doi.org/10.1016/J.RSER.2010.09.020.

Index Note: Page numbers followed by “f” refer to figures.

A

E

Alternating current (AC), 94 Ammonia, 10 11, 11f Analytical Hierarchical Process (AHP), 114 115 Australian Renewable Energy Agency (ARENA), 86

Electrical energy storage (EES), 13 14, 23 24, 61 62 electric double-layer capacitor, 13 14, 14f superconducting magnetic energy storage, 14, 15f Electric double-layer capacitors, 13 14, 14f Electricity market, 66 67 Electrochemical energy storage, 11 12 flow batteries, 12 secondary batteries, 12 Electrodynamic magnetic storage systems, 2 3 Emerging energy storage technologies, 14 16 powerpack, 15 solid-state batteries, 16 Tesla Powerwall, 15 vanadium redox-flow battery, 15 16 Energias de Portugal (EDP), 81 Energy storage systems (ESS), 1 2, 73 74, 137 138 Energy storage technologies barriers and challenges in, 18 20 cost, 18 market risk and business model, 18 19 modeling challenges, 19 regulatory barriers, 19 20 technology risk, 19 case study applications, 16 18 off-grid frequency response in Alaska, 17 off-grid school lighting in Angola, 16 17 time shift and ancillary services case study in China, 17 18

B Black start, 31 Build operate transfer (BOT), 99

C Carbon dioxide (CO2) emissions, 38 39 Chemical energy storage, 9 11 ammonia, 10 11, 11f hydrocarbons, 10 hydrogen, 9, 10f China, 124 125 Climate financing, 100 101 Compound annual growth rate (CAGR), 64 65 Compressed air energy storage (CAES), 2 3, 6, 6f, 90, 121 122 Controls & communication (C&C), 94 Conventional schemes, 54 Cost, 18 Cost-effective analysis, 91 Cost ratio, 92

D Data collection, 113 Demand-side management (DSM), 61 62 Deregulated market, 67, 145 Design-build-operate (DBO), 99 Duck curve, 31 Duqm-Osman PHES-wind system, 76 77

155

156

Index

Energy storage technologies (Continued) chemical energy storage, 9 11 ammonia, 10 11, 11f hydrocarbons, 10 hydrogen, 9, 10f electrical energy storage, 13 14 electric double-layer capacitor, 13 14, 14f superconducting magnetic energy storage, 14, 15f electrochemical energy storage, 11 12 flow batteries, 12 secondary batteries, 12 emerging energy storage technologies, 14 16 powerpack, 15 solid-state batteries, 16 Tesla Powerwall, 15 vanadium redox-flow battery, 15 16 mechanical energy storage systems, 4 7 compressed air energy storage, 6, 6f flywheel energy storage, 6 7, 7f pumped storage hydropower, 4 6, 5f thermal storage systems, 8 9 latent heat storage, 8 sensible heat storage, 8 thermochemical energy storage, 8 9 Engineering, procurement, and construction (EPC), 94, 149 Europe, 123 124 European Union (EU), 73 74

F Federal Energy Regulatory Commission (FERC), 131 Finance, engineer, lease and transfer (FELT), 99 100 Financial and economic assessment indices, 148 149 Financing models, 149 Fixed pumped hydro energy storage, 48 Floating photovoltaics (FPV), 38 Flow batteries, 12 Flywheel energy storage (FES), 6 7, 7f climate/weather, 7 high efficiency, 7 high power density, 7

long life, 7 non-polluting, 7 Fossil fuel, 23 24

G Greenhouse gas (GHG) emissions, 23 24 Grid application, 35 37 double storage PHES-battery powered by renewable energy sources, 36 37 integrated fossil fuel-wind-pumped hydro energy storage system for energy supply and desalination, 36 Grid integration, 94

H Hybrid energy system (HES), 75 Hybrid flow batteries (HFBs), 12 Hybrid or coupled schemes, 54 55 Hydrocarbons, 10 Hydrogen, 9, 10f Hydrogen energy storage system (HESS), 90, 121 122

I Independent Power Producers (IPPs), 67 Independent system operators (ISO), 129 India, 125 Internal rate of return (IRR), 93 International energy agency (IEA), 73 74 International Financial Institutions (IFIs), 101 International Hydropower Association (IHA), 38

J Japan, 124

L Latent heat storage (LHS), 8 Lead-acid batteries, 90, 121 122 Levelized cost of energy (LCOE), 77 Liberalized market, 67 Lithium-ion batteries, 74, 90

Index

Lithium-ion iron phosphate (LFP) batteries, 121 122 Lithium-ion nickel manganese cobalt (NMC) batteries, 121 122 Lithuanian Business Support Agency (LBSA), 85 Load balancing, 27 29

M Market risk and business model, 18 19 Mechanical energy storage systems, 4 7 compressed air energy storage, 6, 6f flywheel energy storage, 6 7, 7f pumped storage hydropower, 4 6, 5f Multi-criteria decision-making (MCDA), 112 113, 140 Multilateral Development Banks (MDBs), 146

N National Electricity Market (NEM), 86 National monopoly, 68 Net present cost, 93 Net present value (NPV), 92 93

O Off-grid/standalone applications, 32 35 hybrid solar-wind-pumped hydro energy storage-diesel generator system, 34 35 hybrid wind-solar-pumped hydro energy storage-battery system, 33 34 wind-pumped hydro energy storage hybrid system, 32 33 Open loop PHES system, 46 Operations & maintenance (O&M), 38, 94 95

P Payback period, 92 Peak shaving, 27 29 Penstock, 45 46 Powerpack, 15 Project viability factors, 91 92 Pumped heat electricity storage, 3 4

157

Pumped hydro energy storage (PHES), 24, 25f, 43 44, 61 62, 74, 89 90, 107 108, 138 addressing environmental impacts, 116 117 advantages and disadvantages, 55 56 barriers to deployment, 125 131 economic barriers, 126 128 in electricity market, 128 130 environmental barriers, 130 131 technical and geographical barriers, 126 black start, 31 capacity of, 64f classifications of, 139 140 climate change impact on, 37 38, 141 conventional, 82 83 cost-effective analysis, 91 current market overview and future trends, 64 66 designs and configuration schemes, 53 55 conventional schemes, 54 hybrid or coupled schemes, 54 55 drivers and barriers to, 141 148 economic factors, 111 112 electricity market for, 66 67 environmental factors, 110 111 environmental impacts, 115 116 cultural, historical, and scenery impacts, 116 environmental factors, 116 impact on fishery industry and aquatic habitat, 115 116 land requirements, 115 water requirements, 115 fast and flexible ramping, 31 financial and economic assessment indices, 92 101 avoided cost of energy, 93 benefit-cost ratio, 92 cost associated with, 94 95 cost associated with decommissioning of, 95 cost comparison of energy storage technologies based on decision maker’s definition of costeffectiveness, 95 96

158

Index

Pumped hydro energy storage (PHES) (Continued) for cost-effectiveness determination, 95 environmental credits and/or subsidies, 93 financing models, 96 101 initial project costs, 92 installed cost components, 94 internal rate of return, 93 levelized cost of energy or electricity, 93 net present cost, 93 net present value, 93 payback period, 92 financing and way forward, 101 financing models, 96 101 build operate transfer, 99 climate financing, 100 101 design-build-operate, 99 engineering, procurement, and construction model, 99 finance, engineer, lease, and transfer, 99 100 fixed pumped hydro energy storage, 48 with floating solar photovoltaic technology, Kruonis, Lithuania, 85 geographic and engineering factors, 109 110 grid stabilization-voltage and frequency regulation, 29 31 hybrid pumped hydro energy storage designs and applications, 32 37 grid application, 35 37 off-grid/standalone applications, 32 35 hybrid systems, 75 79 hybrid pumped hydro energy storagesolar photovoltaic, 77 78 hybrid pumped hydro energy storagewind, 75 77 solar-wind hybrid systems, 78 79 impact of market infrastructure on, 68 70 key factors for, 149 151 increasing digital operation of, 150 investing in public-private research, development and deployment, 149

retrofitting, 151 stimulate innovative operation of, 150 load balancing, 27 29 market overview and future trends, 148 149 financial and economic assessment indices, 148 149 financing models, 149 off-river (closed-loop) pumped hydro systems, 109 with onshore wind in Gaildorf Germany, 84 overview of, 121 123 peak shaving, 27 29 penstock, 45 46 plants, 123 125 China, 124 125 Europe, 123 124 India, 125 Japan, 124 United States, 125 projected regional growth rate for, 65f project viability factors, 91 92 reservoir, 46 47 site considerations for, 140 social factors, 112 socio-economic barriers, 144 146 socio-economic drivers, 141 142 with solar photovoltaic in Montalegre, Portugal, 81 with solar photovoltaic technology, Hatta, United Arab Emirates, 85 with solar photovoltaic technology in the Atacama Desert, Chile, 85 suitability modeling/mapping, 112 115 techno-environmental barriers, 146 148 techno-environmental drivers, 142 144 ternary pumped hydro energy storage, 49 50 with ternary systems, Vorarlberg, Austria, 82 at time of commissioning, 68 traditional (conventional) river-based, 109 types of market infrastructure for, 67 68 liberalized market, 67 national monopoly, 68

Index

regional monopoly, 67 regional monopoly open to independent power producers, 67 variable pumped hydro energy storage, 48 49 with variable speed turbines-Frades II, Portugal, 83 84 way forward, 131 133 with wind and battery in El Hierro island, 80 with wind and solar photovoltaic technology, Kidston, Australia, 86 Pumped storage hydropower, 4 6, 5f

R Redox flow batteries (RFBs), 121 122 Regional monopoly, 67 open to independent power producers, 67 Regulatory barriers, 19 20 Renewable energy (RE), 106, 137 138 Renewable energy sources (RES), 23 24, 73 74 Research, Development and Deployment (RD&D), 149 Reservoir, 46 47 Retrofitting, 151 Rotor spin, 6 7 Round trip efficiency (RTE), 95

S Secondary batteries, 12 Sensible heat storage (SHS), 8 Socio-economic barriers, 144 146 institutional challenges and political interference, 145 liberalized, 145 market failures, 144 national monopoly, 145 project investment and financing, 145 146 public opposition, 144 regional monopoly, 145 regional monopoly open to independent power producers, 145

159

Socio-economic drivers, 141 142 energy arbitrage, 141 142 rural development, 142 Solar energy, 77 Solid-state batteries, 16 Superconducting magnetic energy storage (SMES), 13 14, 15f Sustainable development (SD), 113 Sustainable development goal 7 (SDG 7), 27

T Techno-environmental barriers, 146 148 biodiversity loss, 146 lack of infrastructure support, 147 148 land acquisition challenges, 147 landscape topology, 147 water issues, 146 147 Techno-environmental drivers, 142 144 auxiliary services, 143 144 grid resilience, 142 143 sustainability, 143 utility-scale storage, 142 Ternary pumped hydro energy storage, 49 50 Tesla Powerwall, 15 Thermal storage systems, 8 9 latent heat storage, 8 sensible heat storage, 8 thermochemical energy storage, 8 9 Thermochemical energy storage, 8 9

U United Arab Emirates (UAE), 85 United States, 125

V Vanadium redox-flow battery, 15 16 Variable pumped hydro energy storage, 48 49 Variable renewable energy (VRE), 31, 43 44, 65, 74 75, 148 Vehicle-to-grid (V2G) technology, 61 62