Renewable Energy Technologies and Water Infrastructure 0784415854, 9780784415856

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Renewable Energy Technologies and Water Infrastructure

Advancing Renewable Energy Technologies Committee Edited by

S. Rao Chitikela, Ph.D., P.E., P.Eng. Venkata Gullapalli, Ph.D. William F. Ritter, Ph.D., P.E., D.WRE

Renewable Energy Technologies and Water Infrastructure Prepared by Advancing Renewable Energy Technologies Committee

Edited by S. Rao Chitikela, Ph.D., P.E., P.Eng. Venkata Gullapalli, Ph.D. William F. Ritter, Ph.D., P.E., D.WRE

Published by the American Society of Civil Engineers

Library of Congress Cataloging-in-Publication Data Names: Advancing Renewable Energy Technologies Committee, author. | Chitikela, S. Rao, editor. | Gullapalli, Venkata, editor. | Ritter, William F., editor. Title: Renewable energy technologies and water infrastructure

Description: First edition. | Reston : American Society of Civil Engineers, 2022. | Includes bibliographical references and index. | Summary: “Renewable Energy Technologies and the Water Infrastructure provides an in-depth look at policy, regulation, and the development and application of renewable energies into existing water infrastructure”-Provided by publisher. Identifiers: LCCN 2021022251 | ISBN 9780784415856 (paperback) | ISBN 9780784483664 (ebook) Subjects: LCSH: Waterworks--Technological innovations--United States. | Waterworks-Energy conservation--United States. | Waterworks--Environmental aspects--United States. | Water--Purification--Equipment and supplies--Technological innovations--United States. | Renewable energy sources. Classification: LCC TD485 .E58 2021 | DDC 628.10973--dc23 LC record available at https://lccn.loc.gov/2021022251 Published by American Society of Civil Engineers 1801 Alexander Bell Drive Reston, Virginia 20191-4382 www.asce.org/bookstore|ascelibrary.org Any statements expressed in these materials are those of the individual authors and do not necessarily represent the views of ASCE, which takes no responsibility for any statement made herein. No reference made in this publication to any specific method, product, process, or service constitutes or implies an endorsement, recommendation, or warranty thereof by ASCE. The materials are for general information only and do not represent a standard of ASCE, nor are they intended as a reference in purchase specifications, contracts, regulations, statutes, or any other legal document. ASCE makes no representation or warranty of any kind, whether express or implied, concerning the accuracy, completeness, suitability, or utility of any information, apparatus, product, or process discussed in this publication, and assumes no liability therefor. The information contained in these materials should not be used without first securing competent advice with respect to its suitability for any general or specific application. Anyone utilizing such information assumes all liability arising from such use, including but not limited to infringement of any patent or patents. ASCE and American Society of Civil Engineers—Registered in US Patent and Trademark Office. Photocopies and permissions. Permission to photocopy or reproduce material from ASCE publications can be requested by sending an email to [email protected] or by locating a title in the ASCE Library (https://ascelibrary.org) and using the “Permissions” link. Errata: Errata, if any, can be found at https://doi.org/10.1061/9780784415856. Copyright © 2022 by the American Society of Civil Engineers. All Rights Reserved. ISBN 978-0-7844-1585-6 (print) ISBN 978-0-7844-8366-4 (PDF) Manufactured in the United States of America. 27 26 25 24 23 22    1 2 3 4 5

Contents Preface...........................................................................................................................................ix Acknowledgments................................................................................................................. xiii List of Authors and Reviewers............................................................................................ xv Chapter 1 US Renewable Energy Policy—Analysis and Recommendations..................................................................... 1 Alexander Krokus (Deceased) Introduction.........................................................................................................................1 National Energy Act of 1978 (H.R. 8444 1977-78).........................................2 Energy Policy Act of 2005.....................................................................................2 Energy Independence and Security Act of 2007.........................................3 Food, Conservation, and Energy Act of 2008................................................3 Clean Power Plan of 2015......................................................................................3 Energy Efficiency Resources Standards...........................................................4 Renewable Energy Projects.................................................................................5 Federal Investment Tax Credit............................................................................5 Renewable Production Tax Credit.....................................................................5 Modified Accelerated Cost Recovery System................................................6 Renewable Energy Resources—Review/Recommendations.............................6 Hydropower..............................................................................................................6 Biofuels........................................................................................................................7 Solar Photovoltaic...................................................................................................8 Wind Energy..............................................................................................................8 Future of United States Renewable Energy Policy......................................9 Summary.............................................................................................................................11 References......................................................................................................................... 12 Chapter 2 Renewables and Regulatory Requirements of the United States............................................................................... 17 S. Rao Chitikela Introduction.......................................................................................................................17 US-Code, Law, and Act—Renewable Energy........................................................ 19 Renewable Energy Standards..................................................................................... 20 Renewable Portfolio Standards—The State of Connecticut, Example........ 25 Renewable Portfolio Standards Eligibility—The State of California, Example................................................................................................................... 27 iii

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Local Government on Renewable Energy Projects—State of Virginia, Example................................................................................................................... 28 Solar and Wind Energy Rule—Bureau of Land Management........................ 31 RE Programs—Bureau of Ocean Energy Management..................................... 33 Renewables—Federal Energy Regulatory Commission................................... 34 Summary............................................................................................................................ 35 Disclaimer.......................................................................................................................... 35 References......................................................................................................................... 36 Chapter 3  Biofuels: Ethanol and Biodiesel.............................................. 39 William F. Ritter Ethanol................................................................................................................................ 39 Introduction........................................................................................................... 39 Legislation............................................................................................................... 40 Classes of Ethanol................................................................................................. 41 Processing of Corn Ethanol............................................................................... 42 Cellulosic Ethanol Processing........................................................................... 43 US Ethanol Production.......................................................................................44 Greenhouse Gases............................................................................................... 46 Water Quality Impacts........................................................................................ 48 Pros and Cons of Ethanol................................................................................... 52 Biodiesel............................................................................................................................. 53 Introduction........................................................................................................... 53 Biodiesel Processing............................................................................................ 54 Classes of Biodiesel Blends............................................................................... 55 US Biodiesel Production.................................................................................... 55 Summary............................................................................................................................ 57 References......................................................................................................................... 57 Chapter 4 Micro-Hydropower: Concept, System Design, and Innovations........................................................................ 61 Tamim Younos, Juneseok Lee Introduction...................................................................................................................... 61 Micro-Hydropower Generation: Concept.............................................................. 62 Micro-Hydropower System Design..........................................................................64 Case Study Site......................................................................................................64 Micro-Hydropower System Design Components.................................... 65 Hydraulic Component Design......................................................................... 65 Mechanical Component Design..................................................................... 68 Electrical Component Design.......................................................................... 71 Case Study Project Cost..................................................................................... 75 Cost–Benefit Analysis.......................................................................................... 75 Regulatory Requirements—Case Study Site.............................................. 76 Micro-Hydropower: Viable Technology in Developing Countries................ 76

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S mall-Stream Micro-Hydropower: Challenges and Limitations..................... 78 Emerging Micro- and Small-Hydropower Technologies.................................. 79 Summary............................................................................................................................ 80 Appendix A. Bill of Materials (Equipment, 2013 Prices)..................................... 81 Appendix B. Bill of Materials (Supplies/Materials, 2013 Prices)....................... 88 Acknowledgments......................................................................................................... 90 Disclaimer.......................................................................................................................... 90 References......................................................................................................................... 90 Chapter 5 Biogas-to-Energy—The Combined Heat and Power (CHP) Systems...................................................................................... 93 S. Rao Chitikela, William F. Ritter Introduction...................................................................................................................... 93 Biogas Generation Systems—Theory and Practice............................................ 94 Anaerobic Digestion of Livestock and Poultry Manure.................................... 96 Sludges/Biosolids and Biogas-to-Energy—US Regulations.......................... 101 Biogas-to-Electric Generation and Combined Heat and Power..................102 Economics of Livestock and Poultry Manure Anaerobic Digestion............105 Biogas in the Circular Economy...............................................................................107 Summary.......................................................................................................................... 110 References........................................................................................................................111 Chapter 6  Fuel Cells for Renewable Wastewater Infrastructure.......... 113 Bhuvan Vemuri, Govinda Chilkoor, Jawahar Kalimuthu, Ammi Amarnath, James E. Kilduff, Venkataramana Gadhamshetty Introduction.................................................................................................................... 113 Hydrogen......................................................................................................................... 116 Biological Processes for Hydrogen Production....................................... 116 Dark Fermentation..............................................................................................117 Microbial Electrolysis Cells.............................................................................. 118 Photofermentation............................................................................................ 119 Biophotolysis........................................................................................................ 120 Fuel Cells.......................................................................................................................... 121 Hydrogen Fuel Cells........................................................................................... 124 Alkaline Fuel Cell.................................................................................................125 Phosphoric Acid Fuel Cell................................................................................ 126 Hydrogen and Hydrocarbon Fuel Cells...................................................... 127 Molten Carbonate Fuel Cells.......................................................................... 127 Solid Oxide Fuel Cells........................................................................................ 129 Microbial Fuel Cell..............................................................................................130 Summary.......................................................................................................................... 131 Acknowledgments....................................................................................................... 131 References....................................................................................................................... 131

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Chapter 7 Sustainable Desalination Using Renewable Energy Sources....................................................................... 135 Veera Gnaneswar Gude Introduction.................................................................................................................... 135 Desalination Technologies—Principles of Operation.....................................136 Multistage Flash Desalination........................................................................136 Multieffect Distillation......................................................................................136 Vapor Compression........................................................................................... 137 Energy Efficiency of Thermal Desalination............................................... 137 Reverse Osmosis................................................................................................. 137 Renewable Energy Integration with Desalination Processes........................138 Selection Process of the Desalination Process................................................... 142 Sustainability of Desalination Technologies.......................................................144 Environmental Impacts of Desalination Processes................................144 Brine Disposal......................................................................................................144 Economic Considerations of Renewable Energy-Driven Desalination Processes.......................................................................146 Regulatory Requirements............................................................................... 147 Social Aspects of Desalination Processes.................................................. 147 Summary.......................................................................................................................... 147 References.......................................................................................................................148 Chapter 8  Geothermal Energy................................................................ 151 Audrey Angelos, Guangdong Zhu General Description..................................................................................................... 151 Geothermal Resources................................................................................................ 152 Geothermal Resource Applications........................................................................ 152 Geothermal Power Generation................................................................................154 Power Plant Types.........................................................................................................154 Dry Steam..............................................................................................................154 Flash .................................................................................................................... 155 Organic Rankine Cycle/Binary........................................................................156 Current Status.................................................................................................................156 Worldwide Capacity..........................................................................................156 Technological Distribution.............................................................................. 157 Geothermal Direct Use................................................................................................ 157 Direct Heating Applications......................................................................................158 Mineral Recovery...........................................................................................................158 Energy Storage............................................................................................................... 159 Future Direction............................................................................................................ 159 Enhanced Geothermal Systems.................................................................... 159 Hybridization Opportunities with Concentrating Solar Power.........160 Perspective......................................................................................................................160 References....................................................................................................................... 161

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Chapter 9 Wind Energy—Increasing Resilience in Water Infrastructure.......................................................................... 163 Pamela A. Menges Introduction....................................................................................................................163 Wind Turbine Technologies.......................................................................................165 Wind Technology Powering Mechanical Systems............................................ 167 Efficiency and the Betz Limit.................................................................................... 170 Assessing Power from Wind...................................................................................... 171 Turbine Technology, Applications, and Siting.................................................... 172 Built Environment Wind Turbine............................................................................. 173 Quantifying Turbulence and Turbulence Intensity........................................... 174 Energy and Water.......................................................................................................... 175 Role of Wind Energy in Water Infrastructure Security..................................... 178 Emerging Technologies.............................................................................................. 179 Summary.......................................................................................................................... 181 References....................................................................................................................... 181 Chapter 10  Solar Energy and Water/Wastewater Infrastructure......... 183 Venkata Gullapalli Introduction....................................................................................................................183 Solar Radiation...............................................................................................................183 Solar Photovoltaics.......................................................................................................184 Solar Thermal..................................................................................................................185 Solar Photovoltaics and Concentrating Solar Power Comparison..............186 Solar in Water Industry................................................................................................187 Desalination....................................................................................................................189 Thermal Technologies......................................................................................189 Membrane Technologies.................................................................................190 Solar in Desalination....................................................................................................190 Solar Water Disinfection............................................................................................. 191 Wastewater Processing............................................................................................... 193 Solar in Wastewater Processing...............................................................................194 Summary..........................................................................................................................195 References.......................................................................................................................196 Chapter 11 Renewable Energy Technologies for Water Quality Monitoring............................................................................199 Varun K. Kasaraneni Introduction....................................................................................................................199 Solar-Powered Monitoring Networks....................................................................201 Stormwater Sampling and Monitoring......................................................201 Discharge and Nonpoint Source Monitoring...........................................202 Water Quality Monitoring with Data Buoys..............................................205 Microbial Fuel Cells for Water Quality Monitoring............................................206

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Summary.......................................................................................................................... 211 References....................................................................................................................... 211 Chapter 12 Integrating Renewable Energy in Water Infrastructure: Global Trends and Future Outlook.........................................213 Juneseok Lee, Tamim Younos Introduction.................................................................................................................... 213 Background..................................................................................................................... 214 Water and Energy Nexus................................................................................. 214 Water and Energy Conservation................................................................... 215 Applications of Renewable Energy in the Water Industry............................. 215 Solar Energy......................................................................................................... 215 Wind Energy......................................................................................................... 217 Outlook............................................................................................................................. 218 Summary..........................................................................................................................220 References.......................................................................................................................221 Appendix......................................................................................................225 List of Acronyms and Abbreviations......................................................................225 Index............................................................................................................. 231

Preface Renewable Energy Technologies (RETs) Task Committee of the Environmental and Water Resources Institute (EWRI) was formed in 2016 with the objectives toward accomplishing on water infrastructure and the application of sustainability and resilience requirements. Thus, this task committee has been working on advancement on knowledge of field-proven RETs for the operation of water infrastructure meeting the triple bottom line. The task committee has successfully accomplished the selection and writing on various renewable energy (RE) technologies and proven application to water infrastructure. Following the task committee’s success, a new full standing committee, called the Advancing Renewable Energy Technologies Committee (ARETC) of EWRI, has now been formed. The planning and inclusion of 12 chapters of this book encompass the applicable and critical review details on: RE policy and regulatory requirements; micro-hydro power; biofuels; biogas-to-energy; fuel cells for clean water; sustainable desalination; geothermal energy; solar and wind energy toward a resilient water infrastructure; the application of renewables for the monitoring of water quality; and renewable energy applications to water infrastructure. We, ARETC, pay our sincere and highest respects to Mr. Alexander Krokus—who has been an inspiration, provided constant encouragement, and watched of high expectations for the ARETC—on the sad demise, and we pray for his great soul rest in peace. The book chapters put forward knowledge on the application(s) of renewables toward effectively operating water infrastructure into the future. The authors converged on the following aspects on invaluable and sound policy, regulation, science, and engineering with respect to the development and application of renewables: • To gear up on renewables, subsidies on fossil-fuel energy applications must be significantly reduced and an immediate boost to RE funds should be provided; and this approach would help safeguard humankind from ongoing uncertain weather patterns and havoc. The federal agency efforts, such as by the Bureau of Land Management (BLM), Bureau of Ocean Energy Management (BOEM), and Federal Energy Regulatory Commission (FERC), based on the effective RE legislative actions, are appreciative (to date) in terms of the production and consumption of RE at more than 9.5 quintillion J (9.0 quadrillion Btu) and the resultant significant reduction of greenhouse gases (GHGs). Moreover, the Energy Independence and Security Act (EISA 2007) has been instrumental in the production of renewable fuels (Chapters 1 and 2). ix

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• Chapter 3 contributed by internationally renowned author highlights that the use of soybean oil (one of the vegetable oils) stood at 57% (in 2019) to produce biodiesel, and the market opportunity was rated at 6.8 billion L (1.8 billion gal.) per year. However, the long-term goal for clean renewable fuels was set (in 2007) at 136 billion L (36 billion gal.) per year. • Chapter 4 includes the following recommendations: the small-stream microhydropower generation technologies are “mature technologies,” facilitating distributed or decentralized RE technology and providing a positive environmental impact compared with that of large-dam hydropower; and they must follow the local, state, and national environmental and energy regulatory guidelines to accomplish potential success in micro-hydropower. • According to the current and historically well-known sources, Chapter 5 fortifies the effective use of municipal wastewater sludges (the by-product solids as generated from wastewater to clean water processing), fats–oils– grease (FOG) feedstocks, vegetable and food wastes, livestock manure(s), and other (highly) biodegradable municipal and industrial wastes to the successful operation of biogas-to-energy-distributed RE systems. Also, the economics of biogas-to-energy systems are proven worldwide and are a guaranteed positive cash flow (with a short payback time). Most importantly, biogas-to-energy systems also provide pathways to making environmentally friendly by-products and are globally required in the “circular economies.” • Fuel cell development and operation based on wastewater systems has been rapidly advancing, and current research results are highly utilized worldwide for effective and immediate applications. Chapter 6 addresses the key requirements of various fuel-cell technologies, including microbial fuel cells (MFCs). The challenges—production, storage, and supply—posed to biohydrogen infrastructure are elucidated, where there is rigorous research requirement for fermentation technologies, control of fouling, and the development of effective catalysts and electrode materials for fuel-cell operation(s). The authors emphasize on the use of MFCs for the potential NetZeroEnergy operation of wastewater infrastructure. • Desalination operations are witnessing an unprecedented growth globally because of increased freshwater demands. Specifically, RO processes or technologies that dominate this field help make freshwater from brackish, saline, and clean effluent (to name a few) water resources. In Chapter 7, the author clearly identifies the need for research on membrane distillation and adsorption desalination technologies for harvesting solar energy and waste heat for (fresh) water production. The author also outlines the priority for developing environmentally responsible and RE-integrated desalination systems. • Geothermal energy has been playing a significant role in HVAC systems globally. In Chapter 8, the scientist authors elucidate on geothermal energy and its commercial challenges, and the required improvements. It is vital

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to note that current improvements focus on implementing enhanced geothermal systems (EGSs) and binary power plants that will work based on “lower geothermal resource temperatures,” and the scientists are outspoken on “geothermal energy has the potential to solve many of the world’s energy problems.” • The application of RE systems with resilience is now critical and is a case for the (immediate) future. This wind energy expert in Chapter 9 unequivocally states, “The capability to implement resilience in the built infrastructure to tolerate energy loss as well as the outcome of natural and man-made disasters including highly volatile aspects of climate change, is key to establishing criteria for resilience in critical water infrastructures.” The current advancements include hybrid wind energy systems that can well support microgrids and can also provide real-time data on water security and availability. • Need for developing significant level(s) of energy—to operate high standard water and wastewater treatment trains—owing to polluted resource water and spent water and the resultant unwanted GHG emissions of fossil-fuel firing for power generation is critical and needs a clear mandate. It is important to note the critical role of RE systems in the context of the current climate patterns, the loss of water due to the ever-increasing impervious areas in worldwide development activities, and the associated droughts. In Chapter 10, solar energy is detailed for applications to both water and wastewater systems and infrastructure. • Current need for environmental quality monitoring is seen to be enormous, and, so, Chapter 11 addresses the importance of water quality monitoring through the use of RE systems. It is not an easy task to list out the various requirements for such monitoring, and this is where the author’s effort in writing such a chapter becomes commendable. The large wireless monitoring networks [operating the Internet of Things (IoT) for data collection and SCADA reporting] for water quality monitoring can make use of in situ RE sources, such as solar power and MFCs. The emphasis on the use of RE-based monitoring network systems also comes with a caution on security requirements. • Chapter 12 provides real-time project examples of water infrastructure integrated with solar and/or wind energy systems. It is clearly shown that RE systems can be used for both demand and supply side operations of water infrastructure. Based on the proven applications detailed in the chapter, the authors are insistent on RE integration with water infrastructure so as to remove the dependence on fossil-fuel-generated power.

Acknowledgments ARETC and EWRI greatly appreciate the following institutions and firms for supporting the authors’ and reviewers’ efforts in the preparation of this book: Central State University, Wilberforce, OH Electric Power Research Institute, Palo Alto, CA Gannon University, Erie, PA Green Water-Infrastructure Academy, Washington, DC Louisville Parks and Recreation, Louisville, KY Manhattan College, Riverdale, NY Mississippi State University, Mississippi State, MS National Renewable Energy Laboratory (NREL), Golden, CO Portland State University, Portland, OR RC-WEE Solutions LLC, Dublin, OH Rensselaer Polytechnic Institute, Troy, NY Ritter Engineering, Elkton, MD Rose-Hulman Institute of Technology, Terre Haute, IN South Dakota School of Mines and Technology, Rapid City, SD Star Sailor Energy, Inc., Cincinnati, OH University of Delaware, Newark, DE University of Illinois at Urbana-Champaign, Urbana, IL ARETC honors the Sustainability Committee and Interdisciplinary Council of EWRI for providing continuous support and appreciates the ARETC members on successfully completing this book.

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List of Authors and Reviewers Ammi Amarnath Ph.D. Candidate Energy Efficiency and Demand Response Division Electric Power Research Institute Palo Alto, CA 94304 Audrey Angelos Research Scientist Thermal Sciences Group National Renewable Energy Laboratory (NREL) Golden, CO 80401 Govinda Chilkoor Ph.D. Candidate Civil and Environmental Engineering South Dakota School of Mines and Technology Rapid City, SD 57701 S. Rao Chitikela Executive, Water, Energy, & EHSs RC-WEE Solutions LLC Adjunct Professor & Instructor Central State University (1890 Land-Grant Institution) Dublin, OH 43016 Contact at: [email protected] Venkataramana Gadhamshetty Associate Professor Civil and Environmental Engineering South Dakota School of Mines and Technology Rapid City, SD 57701 Contact at: [email protected]

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List of Authors and Reviewers

Veera Gnaneswar Gude Associate Professor Civil and Environmental Engineering Mississippi State University Mississippi State, MS 39762 Contact at: [email protected] Venkata Gullapalli Engineer II Louisville Parks and Recreation City of Louisville Louisville, KY 40213 Contact at: [email protected] Margaret A. Helms Graduate Student Environmental Science and Engineering Gannon University Erie, PA 16541 Contact at: [email protected] Jawahar Kalimuthu Research Assistant II Civil and Environmental Engineering South Dakota School of Mines and Technology Rapid City, SD 57701 Ramanitharan Kandiah Professor Center for Water Resources Management Central State University Wilberforce, OH 45384 Contact at: [email protected] Varun K. Kasaraneni Assistant Professor Environmental Science and Engineering Gannon University Erie, PA 16541 Contact at: [email protected]

List of Authors and Reviewers

James E. Kilduff Ph.D. Candidate Civil and Environmental Engineering Rensselaer Polytechnic Institute Troy, NY 12180 Alexander Krokus (Deceased) Fellow, Institute for Sustainable Solutions Research Analyst, School of Government Portland State University Portland, OR 97207 Juneseok Lee Associate Professor Civil and Environmental Engineering Manhattan College Riverdale, NY 10471 Contact at: [email protected] Pamela A. Menges President Star Sailor Energy, Inc. Cincinnati, OH 45224 Contact at: [email protected] William F. Ritter Professor Emeritus University of Delaware Newark, DE 19702 and Ritter Engineering Elkton, MD 21921 Contact at: [email protected] Namita Shrestha Assistant Professor Civil and Environmental Engineering Rose-Hulman Institute of Technology Terre Haute, IN 47803 Contact at: [email protected]

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List of Authors and Reviewers

Ashlynn S. Stillwell Associate Professor Civil and Environmental Engineering University of Illinois at Urbana-Champaign Urbana, IL 61801 Contact at: [email protected] Bhuvan Vemuri Ph.D. Candidate Civil and Environmental Engineering South Dakota School of Mines and Technology Rapid City, SD 57701 Contact at: [email protected] Tamim Younos Founder and President Green Water-Infrastructure Academy Washington, DC 20001 Contact at: [email protected] Guangdong Zhu Research Scientist Thermal Sciences Group National Renewable Energy Laboratory (NREL) Golden, CO 80401 Contact at: [email protected]

CHAPTER 1

US Renewable Energy Policy—Analysis and Recommendations Alexander Krokus (Deceased)

INTRODUCTION The first industrial use of hydropower for energy generation that transpired in the United States occurred in Grand Rapids, Michigan, during 1880, when 16 brusharc lamps were powered by a water turbine (Pandey and Karki 2017). By 1920, the United States had implemented its first federal energy policy regarding renewable energy production, when it enacted the Federal Water Power Act (FWPA) of 1920 (16 U.S.C. §791a). FWPA promoted the establishment of renewable energy policy nationally, by creating hydroelectric power plants for energy generation, and promulgated the formation of the Federal Power Commission, which later, in 1977, became the Federal Energy Regulatory Commission (FERC). This act was later, in 1935, renamed Federal Power Act (FPA) and increased FERC’s jurisdiction to encompass all interstate electricity transmission. On April 18, 1977, ex-US President Jimmy Carter delivered a speech to the nation that would still be a relevant concern in modern time. “We must not be selfish or timid if we hope to have a decent world for our children and our grandchildren … By acting now we can control our future instead of letting the future control us …  (referring to) the oil and natural gas that we rely on for 75% of our energy … [During 2017, the United States utilized fossil fuels to facilitate 80.9% of all energy consumption (USEIA 2018a).] During the 1950s, people used twice as much oil as during the 1940s. During the 1960s, we used twice as much as during the 1950s. And in each of those decades, more oil was consumed than in all of man’s previous history combined” (Carter 1977). This speech was President Carter’s precursor to introducing his National Energy Plan to the US Congress, which led to the establishment of the National Energy Act (NEA) of 1978, which contained major statutes devoted to harnessing renewable energy resources. NEA of 1978 promulgated the Energy Tax Act of 1978, Pub. L. No. 95-618, 92 Stat. 1

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3174, which amended §1954 of the Internal Revenue Code to grant an income tax credit for individuals utilizing solar, wind, or geothermal energy generation for their personal residence (HR 5263 1977-78). This act also created residential energy credit for the tax imposed for energy conservation [26 U.S.C. §44C(a)(1)] and renewable source expenditures [26 U.S.C. §44C(a)(2)]. §44C(5)(A) states that energy “installed in connection with a dwelling, transmits or uses (i) solar energy, energy derived from the geothermal deposits [as defined in Section 613(e) (3)], or any other form of renewable energy which the Secretary specifies by regulations, for the purpose of heating or cooling such dwelling or providing hot water for use within such dwelling, or (ii) wind energy for nonbusiness residential purposes.

National Energy Act of 1978 (H.R. 8444 1977-78) NEA of 1978 also created the Energy Security Act of 1980, 42 U.S.C. §8701 et seq. Title I (Synthetic Fuels Corporation Act), §§100-195, which created the Synthetic Fuels Corporation (Section, Pub. L. 96-294, Title I, § 100, June 30, 1980, 94 Stat. 616, was omitted from the code because of the termination of the United States Synthetic Fuels Corporation and repealed in 1985.) to collaborate with industry to develop a market for synthetic liquid fuels. Research and development was transferred from the US Department of Energy into a public–private partnership to accelerate achieving successful strategies. Title II (Biomass Energy and Alcohol Fuels Act) of NEA of 1978, §§201-274, granted loan guarantees for small-scale biomass energy projects and established the federal Office of Alcohol Fuels and the Office of Energy from Municipal Waste. Title IV (Renewable Energy Initiatives), §§401-409, established economic incentives for the utilization of renewable energy resources. Title V (Solar Energy and Energy Conservation) of NEA of 1978, §§501-597 (Energy Policy Act of 1992, 16 U.S.C. Chapter 46 §2601 et seq. repealed Title V of the Energy Security Act of 1980.), encouraged the expansion of solar energy and established the Solar Energy and Energy Conservation Bank, and 42 U.S.C. §8201, §§241-248, established solar energy improvement loans. Title VI (Geothermal Energy Act) of NEA of 1978, §§601-644, authorized federal loans from the Geothermal Resources Development Fund for research associated with exploration and the economic viability of a geothermal reservoir. It also promoted the usage of geothermal energy as a feasible method to implement in new federal buildings. The National Energy Conservation Policy Act (NECPA) of 1978, Pub. L. No. 95-619, 92 Stat. 3206, replaced the minimum energy performance standards set forth in the Energy Policy and Conservation Act (EPCA) of 1975, Pub. L. No. 94-163, 89 Stat. 871, and transformed energy standards from voluntary to mandatory. The Public Utility Regulatory Policies Act (PURPA) of 1978, Pub. L. No. 95-617, 92 Stat. 3117, advocated for the usage of renewable energy implementation and encouraged the creation of cogeneration plants. Regulatory authority was solely delegated to the states.

Energy Policy Act of 2005 The next monumental piece of US federal energy policy was enacted over two decades later, when the Energy Policy Act (EPAct) of 2005, 42 U.S.C. §15801

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et seq., became public law. EPAct of 2005 enabled tax incentives for individuals increasing energy efficiency in their homes and also for consumers to buy or lease hybrid vehicles. EPAct of 2005 also raised the mandatory percentage of renewable fuel contained in gasoline. Succeeding the repeal of the Public Utilities Holding Act of 1935 [15 U.S.C. §§79-79(z)(6)] by the enactment of EPAct of 2005, FERC permitted immense capital investment into the US oil and gas sector, allowing for emerging new unconventional oil and gas formations to be exploited, by utilizing horizontal drilling techniques, enabling the United States, to become the global leader in oil and gas production in 2018 (USEIA 2018b, British Petroleum 2019).

Energy Independence and Security Act of 2007 The Energy Independence and Security Act of 2007, 42 U.S.C. Ch. 152 §17001 et seq., increased the Corporate Average Fuel Economy (CAFE) standards to 56 kmph (35 mpg) for passenger automobiles by 2020. These Renewable Fuel Standards (RFS) had resulted in amplified biofuel production for 136 billion liters (36 billion gal.) by 2022, with 79.5 billion liters (21 billion gal.) derived from noncornstarch products [40 CFR Part 80, FR, Vol. 81, No. 238 (December 12, 2016)].

Food, Conservation, and Energy Act of 2008 The enactment of the Food, Conservation, and Energy Act (Farm Bill) of 2008, Pub. L. No. 110-234, 122 Stat. 923, provided access to federal loans for biorefineries and monetary compensation to facilitate the expansion of innovative biofuels and also expanded the existing Rural Energy for America Program. The Biomass Crop Assistance Program (BCAP, §9001), initiated by the 2008 Farm Bill, was reauthorized with modifications by the 2014 Farm Bill (Agricultural Act of 2014, Pub L. No. 113-79). The revised BCAP provides financial assistance to farmers and forest landowners who are growing, maintaining, or harvesting biomass that can be utilized for energy. This assistance includes payments for cultivating new biomass crops. (The BCAP has the ability to fund up to 50% of costs affiliated with the establishment of a new perennial energy crop or biomass crop.) Annual maintenance payments can be used to cultivate biomass crops until they mature, up to 5 years for an herbaceous crop, or up to 15 years for a woody crop. The BCAP can also provide monetary support for the cost of sustainable harvesting and the transportation of agricultural or forest residues to an energy conversion facility. [Animal waste, bagasse, food and yard waste, and algae are ineligible for retrieval payments. §9003 “Eliminates grants to assist in paying the costs of development and construction of demonstration-scale biorefineries to demonstrate the commercial viability of one or more processes for converting renewable biomass to advanced biofuels.” §9011 repeals the forest biomass for energy program (§9012 of the Farm Security and Rural Investment Act of 2002, 7 U.S.C. §8112).]

Clean Power Plan of 2015 The Clean Power Plan (CPP) of 2015 (40 CFR Part 60, FR, Vol. 80, No. 64661-65120, October 23, 2015) was the first comprehensive national strategy to mitigate carbon

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emissions from existing fossil fuel-fired electric generating units, providing states flexibility in their methods of implementation. States were permitted the option to choose either achieving rate-based or mass-based goals, which were calculated by applying performance rates for fossil fuel power plants versus their entire energy amalgam. Individual state plans could include various methods to achieve their goals, including investments for energy conservation, or by implementing additional wind or solar installations. On June 19, 2019, EPA repealed the CPP and replaced it with the Affordable Clean Energy (ACE) rule, amending §111(d) of the Clean Air Act. By 2030, the ACE rule is expected to reduce CO2 emissions from electric generating units to 35% below 2005 levels (EPA 2019a). During the first session of the 116th Congress, Senator Tom Udall (NM-3) proposed the Renewable Electricity Standard (RES) Act of 2019, which attempts to amend Title VI of the PURPA of 1978 to accelerate our nationwide transition to renewable energy generation. By 2050, §2(2) of the RES Act of 2019 requires every state to transition to 100% carbon-free electricity but encourages states to devise their own strategies to obtain these (ambitious) goals. The RES Act of 2019 does provide an achievable ramp-up approach, requiring annual percentage increases of renewable energy ranging from 1.5% to 2.5%. By 2035, these reductions, if met, will assist the nation in attaining 50% of renewable energy generation. The issuance of federal renewable energy credits would be awarded to states which comply with the national standards set forth in this bill.

Energy Efficiency Resources Standards Twenty-seven states are presently using Energy Efficiency Resources Standards’ (EERS) policies, which mandate electricity reduction methods. Eighteen states have EERS policies for natural gas usage. In 1999, Texas was the first state to implement an EERS. Only 29 states in the United States have adopted Renewable Portfolio Standards (RPS) to establish renewable energy goals (NCSL 2019). Renewable energy resources allowable for RPS compliance include wind, solar, biomass, geothermal, and hydroelectric facilities. Certain states allow for utilizing landfill gas and tidal energy and for implementing energy efficiency standards. In 2018, Massachusetts, California, and Rhode Island were the top three states leading in energy efficiency because of the employment of various environmental policy strategies (ACEEE 2018). Leading by Example (LBE) initiatives, which include building energy efficiency, nonbuilding energy efficiency, greenhouse gas (GHG) reduction, green buildings, renewable energy, and sustainable transportation, have proven to be successful in the State of Massachusetts. The LBE method, initiated by the 71st Governor of Massachusetts Deval Patrick, proclaims that “state government has an obligation to lead by example and demonstrate that large entities such as state colleges and universities, prisons, hospitals and others can make significant progress in reducing their environmental impacts, thereby providing a model for businesses and private citizens” (Mass. Exec. Order No. 484, April 18, 2007). In 2012, the LBE partners in Massachusetts achieved their GHG emission reduction goal of 25% below 2002 levels and, in 2050, plan to reduce state government GHG emissions by 80% (MA-DER 2019a).

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Renewable Energy Projects Renewable energy projects immensely vary nationally and are dictated by state and local policy. The actual renewable potential for a specific form of energy generation often is not accounted for when formulating legislation. The States of Massachusetts, California, New Jersey, Arizona, New York, Nevada, Texas, and Pennsylvania account for 99.5% of the nations installed solar photovoltaic (PV) capacity; yet, only California, Nevada, and Texas are ranked in the top 10 states possessing the greatest potential for harnessing solar PV energy (EPA 2019b). Despite achieving more than 1 million solar PV installations nationally in 2016, and 9.8 × 1013 J/h (27.2 GW) of installed capacity (Unger 2016), solar PV contributed to only 1.4% of the total energy generated (DOE 2017a). In 2017, national leaders in solar PV installed capacity, such as Massachusetts, generated 7.3 × 1015 J (2,030,879 MWh) of solar PV and 1.2 × 1016 J (3,353,712 MWh) of wind power. They were able to generate over 4.7 × 1015 J (1.3 million MWh) more energy utilizing wind, despite possessing 21 times less installed capacity compared with solar PV (MA-DER 2019b).

Federal Investment Tax Credit The rise of the solar PV industry has been driven by a federal investment tax credit (ITC), often referred to as the solar tax credit, which permits a federal tax deduction of 30% for costs associated with residential and commercial installations. The solar ITC was a by-product of §1337(a)(A)(i) of EPAct of 2005 and has allowed the national solar PV industry to expand by 10,000% (USEIA 2019). The residential ITC (26 U.S.C. §25D) and the commercial ITC (26 U.S.C. §48) diminished from 30% in 2019 to 26% in 2020, 22% in 2021, and to 10% after January 1, 2021. Besides supporting solar investments, the allowable residential ITCs also apply to small wind energy projects [§(a)(4)] and geothermal heat pump expenditures [§(a)(5)]. The ITC for renewable energy generation was extended by the Consolidated Appropriations Act of 2016, Pub. L. 114-113, 129 Stat. 2242 (H.R. 2029, 2015–2016), and currently a new 5 year extension has been introduced by both chambers of the US Congress. The House bill (Renewable Energy Extension Act of 2019) is supported by three republican Congressmen, and the Senate bill’s proponents are 15 democratic Senators. Besides amending §48 of the Internal Revenue Code of 1986 for solar PV, this proposed policy also extends the ITC for additional energy technologies about to sunset, which includes fiber-optic solar, qualified fuel cells, and small wind energy [§2(b)(2)].

Renewable Production Tax Credit The Consolidated Appropriations Act of 2016 also enabled an extension for the renewable production tax credit (PTC), which is a per kilowatt hour tax credit indexed for inflation on energy generated by qualified renewable resources, differing from ITC, which grants a tax credit based on the monetary assets invested, not the amount of electricity actually produced (26 U.S.C. §45). With the exception of wind energy, every form of renewable energy generation PTC expired

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on January 1, 2018. Yet, projects initiated before the expiration date will have access to the PTC for their initial 10 years of energy production. This applies to all qualified facilities, which includes wind, closed-looped biomass, and geothermal receiving 2.4¢ per kWh and open-loop biomass, small irrigation power, municipal solid waste, hydropower, and hydrokinetic receiving 1.2¢ per kWh. The renewable PTC has been extended 11 times since it first became law subsequent to the enactment of the EPAct of 1992, Pub. L. No. 102-486. The most recent extension transpired when the Bipartisan Budget Act of 2018, Pub. L. No. 115-123, provided a retroactive PTC for all nonwind renewable energy installations conducted before the end of 2017 (HR 1892, 2017-2018). The federal PTC has played a vital role in promoting wind energy implementation nationally and has increased wind energy installations substantially, 720 GJ (200 MW) per state annually (Shrimali et al. 2015). The enactment of a 1 year extension for the renewable PTC is presently being debated by the US House of Representatives (H.R. 3301, 2019 to 2020).

Modified Accelerated Cost Recovery System The Modified Accelerated Cost Recovery System (MACRS) is a complex set of tax policies that classifies almost every form of renewable energy generation’s assets as a 5 year property, which allows taxpayers to recover their entire depreciation allowance in a 5 year period of time [26 U.S.C. §168(e)(3)(B)(vi)(I)]. The Emergency Economic Stabilization Act of 2008, Pub. L. No. 110-343, 122 Stat. 3765 permitted bonus depreciation, which provides a 50% first-year bonus depreciation for qualifying renewable energy investments. The Tax Relief, Unemployment Insurance Reauthorization, and Job Creation Act of 2010, Pub. L. No. 111-312, 124 Stat. 3296 increased the first-year bonus depreciation to 100%. The Tax Cuts and Jobs Act of 2017, Pub. L. No. 115-97, 131 Stat. 2054 expanded bonus depreciation tax relief to cover both new and used equipment to be expensed at 100%, during the first year of purchase, for all qualified property secured and operational after September 27, 2017, up until January 1, 2023 (HR 1, 2017). Despite this favorable federal tax policy, the wind industry has seldom taken advantage of this generous bonus depreciation option (DOE 2018).

RENEWABLE ENERGY RESOURCES—REVIEW/ RECOMMENDATIONS Hydropower The 1986 amendments to FPA of 1920 (Electric Consumers Protection Act of 1986, Pub. L. 99-495, 100 Stat. 1243) devised protection strategies for specific aquatic species [16 USC §803(j)1)] [“(j) Fish and wildlife protection, mitigation and enhancement; consideration of recommendations; findings (1) That in order to adequately and equitably protect, mitigate damages to, and enhance,

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fish and wildlife (including related spawning grounds and habitat) affected by the development, operation, and management of the project, each license issued under this subchapter shall include conditions for such protection, mitigation, and enhancement. Subject to paragraph (2), such conditions shall be based on recommendations received pursuant to the Fish and Wildlife Coordination Act (16 U.S.C. 661 et seq.) from the National Marine Fisheries Service, the United States Fish and Wildlife Service, and State fish and wildlife agencies.”] adversely affected by hydroelectric power plants. Despite hydropower’s favorable sustainability attributes and low carbon footprint, and the fact that it provides the vast majority of renewable energy generation nationally (USEPA 2019a), this form of energy may necessitate stricter federal policy measures to mitigate ecological abnormalities. Almost three decades subsequent to the passage of the Electric Consumers Protection Act of 1986, scientists compared the impairments with 239 endangered freshwater fish species in the United States, which contained major threat categories, as follows: “dams/impoundments, invasive/introduced species, altered hydrologic flow/channelization, overharvesting/overfishing, pollution/ water quality, sedimentation/turbidity/siltation, excess water consumption/ withdrawal, and hybridization”; in addition, it was revealed that a majority of aquatic species had multiple threats contributing to their decline, and surprisingly, dams/impoundments are the primary biological inhibitor (McDonald et al. 2012). Future policies can diminish this adverse effect by mandating that dissolvedoxygen (DO) monitoring stations are located both upstream and downstream from the facility while performing near-continuous monitoring. A majority of freshwater aquatic species necessitate DO levels greater than 5 mg/L for optimum growth and to avoid chronic effects on survival (Niklitschek and Secor 2009, Stoklosa et  al. 2018, KY-NREPC 2019). An alternate method to conventional damming is the utilization of instream turbine technology. This strategy is less environmentally destructive and can reduce unintentional damage to marine life residing in close proximity to hydropower operations (Wang et al. 2012a, b).

Biofuels The multiple federal policy definitions for the term biomass have complicated decisions pertaining to land usage and which feedstock to utilize, especially when pertaining to RFSs and tax incentives. The US Congress has redefined the meaning of biomass in 14 separate pieces of federal legislation during the last 15 years (CRS 2019). As a result of the complexity surrounding the legal meaning of biomass, research and development projects, including the production of biomass for energy conversion, can encounter unnecessary obstacles in their effort to fully exploit this emerging method of energy generation. On May 22, 2019, Senator Ron Wyden (OR-3) introduced a bill (S. 1614) in an attempt to refine the meaning of renewable biomass under §211(o)(1)(I) of the Clean Air Act [42 USC §7535(o)(1) (I)], which presently prohibits the usage of biomass derived from federal lands. This legislative concept permits obtaining biomass from designated federal lands, necessitating ecological restoration.

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Certain ethanol–gasoline mixtures produce higher evaporative emissions from fuel tanks and distribution equipment as compared to gasoline, which can release toxic substances leading to the formation of harmful smog (USEIA 2019b). Because the lifecycle emissions of ethanol is reliant on the materials used and the methods employed for processing, future policy measures can lessen the environmental impact by promoting the conversion of waste into gases, or by other alternates, such as utilizing algae and additional microorganisms to generate fuel from water or solar radiation. Biofuels derived from waste products including municipal and crop waste can eliminate this complication and may alleviate the formation of fugitive GHG emissions resulting from land-use changes.

Solar Photovoltaic Solar PV energy has successfully been utilized globally. There is also debate associated with the amount of GHG emissions yielded during the solar PV manufacturing process (WNA 2011, Stamford and Azapagic 2014). Factories located in China currently use nitrogen trifluoride (NF3) and sulfur hexafluoride (SF6) during the etching process in PV panel manufacturing. Chinese solar factories primarily manufacture PV panels that use crystalline silicon (c-Si) cells (Fang et  al. 2013). A majority of the remaining panels produced are either cadmium telluride (CdTe) or copper–indium-gallium–selenide (CISG). The residual supply of rare earth minerals required to these various forms of PV manufacturing has been diminishing rapidly. China occupies 97% of these minerals and has enacted production and export quotas. This immense uncertainty relating to the future supply of these rare earth minerals poses a substantial threat to the solar PV industry (Than 2018). Additional federal funding must be allocated for developing alternate methods for harnessing the Sun’s energy and to also create an etching gas that is environmentally friendly. If we could capture 100% of the Sun’s energy reaching the Earth in only the State of Texas, then it would generate over three-hundred times the aggregate power of every power plant globally (UTIA 2019). Future federal policy must amend the Resource Conservation and Recovery Act, 42 USC §6901 et seq., and include a section specifically pertaining to the end-of-life disposal for solar PV systems, and establish a reclassification method for nanomaterials by toxicity, rather than by sheer weight in the EPA TRI (Toxics Release Inventory) database. Nanomaterials often exhibit transmuted properties as compared to larger sized particles of similar material and have the potential to be extremely toxic in diminutive dosages; yet, this is not taken into consideration when establishing regulations or constructing material safety data sheets (MSDSs).

Wind Energy According to the United States Department of Energy (DOE), despite a significant decrease in the costs associated with wind installations, the initial capital expenditure for wind projects “might not be the most profitable use of the land,” and wind turbines have the potential to generate “noise and aesthetic

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pollution” and also avian mortalities; yet, a majority of these complications “have been resolved or greatly reduced” (DOE 2019b). Erickson et al. (2014) performed a meta-analysis based on 116 prior studies focusing on more than 70 wind energy facilities in the United States and Canada and estimated that 134,000 to 230,000 small-passerine birds (less than 0.1%), the most abundant bird category in the United States and Canada, collide with wind turbines annually. The United States installed 1.9 × 1014 J/h (52,500 MW) of wind energy capabilities in 2017, raising the national total capacity to 1.9 × 1015 J/h (539,000 MW). The State of Texas led the nation with 8.1 × 1013 (22,599 MW) of installed capacity, and the States of Iowa, Kansas, Oklahoma, and South Dakota used wind energy to supply 30% to 37% of all in-state electricity generation. Denmark was able to supply 48% of all energy generation nationally by wind in 2017, and Ireland and Portugal supplied approximately 30% (DOE 2018). Offshore wind potential in the United States is substantial and can be utilized if favorable federal and state policies are formed to aid the development of these facilities. The State of Rhode Island became the first state in the nation to develop an offshore wind facility lock Island Wind Farm)in the United States, during 2016, and additional projects in neighboring states are being contemplated by policymakers (USEIA 2019c). This includes a $4.5 million investment by Danish company Orsted, Fredericia, who plans to install an additional offshore wind farm in Rhode Island consisting of up to 50 new wind turbines that will have the ability to power approximately 270,000 residential homes (McDermott 2019). According to DOE (2015), the “next generation of wind turbines could make reliable, costeffective wind power a reality in all 50 states.” This reality can be achieved by implementing new advanced wind turbines, which utilize taller towers and longer blades that rely on consistent wind patterns found at higher elevations. The evolution of wind power generation has made substantial advances in terms of technological development and is now labeled globally as the “cheapest and most reliable energy technologies in the market” (GWEC 2015). During 2016, the wind power sector represented the third largest share of electric power generation employment nationally. At the beginning of 2017, the US wind sector employed 101,738 individuals, rising 32% in just 1 year (DOE 2017b) and, by 2050, could facilitate an additional 600,000 jobs (DOE 2019b).

Future of United States Renewable Energy Policy Future US energy policy must be focused on restricting the supply side of fossil fuel generation, the production aspects, to reduce the amount extracted rather than implementing demand-side regulations (such as a cap-and-trade on emissions), which allows for the continuous expansion of fossil fuel infrastructure. USEIA has predicted a substantial increase (of 99%) in unconventional oil and gas recovery to be experienced by 2040 (USEIA 2016). As long as generous federal tax subsidies endure for the oil and gas industry for the exploration, extraction, and also the transport of fossil fuels, efforts to shift the United States to more reliance on renewable energy generation will be compromised.

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The United Nations Intergovernmental Panel on Climate Change (UN-IPCC) has alerted the world of the possibility of irreversible negative environmental impacts occurring in the imminent future if fossil fuel emissions are not significantly reduced. To avoid a 2°C increase in global warming relative to preindustrial times, GHGs must become stable at 450 ppm or less (UN-IPCC 2014). The Fifth Assessment Report concluded that “many aspects of climate change and associated impacts will continue for centuries, even if anthropogenic emissions of greenhouse gases are stopped. The risks of abrupt or irreversible changes increase as the magnitude of the warming increases” (UN-IPCC 2014). At the present time, the Earth’s atmosphere is 408 ppm CO2 and has been averaging a 2.8 ppm increase for the past decade (JAXA 2019), leaving us approximately 15 years to find a solution to mitigate unalterable ecological consequences. A supply-side cap-and-trade system restricting extraction and production, rather than emissions, would diminish pollution and allow the renewable energy industry a fairer chance to politically compete with the fossil fuel industry (Collier and Venables 2014, Lazarus et al. 2015). A global shift from fossil fuel policies focusing on regional demand to policies dedicated to lowering global supply, by enacting global quantity constraints, export taxes, and by taxing interest income earned with a minimum source tax, would diminish GHG emissions and increase the favorability for renewable energy implementation. Reducing the amount of federal subsidies for fossil fuels would also encourage the formation of renewable energy installations. For example, the expensing of exploration and development costs [26 USC §263(c)] [“(c) Intangible drilling and development costs in the case of oil and gas wells and geothermal wells: Notwithstanding subsection (a), and except as provided in subsection (i), regulations shall be prescribed by the Secretary under this subtitle corresponding to the regulations which granted the option to deduct as expenses intangible drilling and development costs in the case of oil and gas wells and which were recognized and approved by the Congress in House Concurrent Resolution 50, Seventy-ninth Congress. Such regulations shall also grant the option to deduct as expenses intangible drilling and development costs in the case of wells drilled for any geothermal deposit [as defined in section 613(e)(2)] to the same extent and in the same manner as such expenses are deductible in the case of oil and gas wells. This subsection shall not apply with respect to any costs to which any deduction is allowed under section 59(e) or 291.”] provision, an over $1 billion tax expenditure annually, permits oil and natural gas producers to expense exploration and development expenditures (which include certain intangible drilling and development costs) rather than capitalizing and depreciating them over time. The aggregate of federal energy subsidies in the United States for natural gas and oil were over $51 billion in 2016 (up from $35 billion in 2010), 500% higher than the $10 billion for biomass, hydroelectric, wind, solar, and geothermal combined (USEIA 2018c). Even the US coal industry, despite a $7 billion decrease in federal assistance since 2010, acquired almost $5 billion more in tax subsidies than all renewables combined in 2016 (Table 1-1). The total amount of renewable energy produced in the United States almost doubled from 2008 to 2018, rising to 2.7 × 1018 J (742 million MWh), facilitating 18% of the total energy generated nationally (USEIA 2019d). This upsurge in

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Table 1-1.  Total Energy Subsidies for FY 2010, FY 2013, and FY 2016. Indicators

FY 2010

FY 2013

FY 2016

Total energy subsides and support (million 2016 dollars) US energy consumption US energy production  US natural gas (dry and liquids)  US crude oil  US coal  US nuclear  US biomass  US hydroelectric  US wind  US solar  US geothermal

37,992

29,335

14,983

96,850 73,695 24,105 11,512 21,657 8,318 4,358 2,588 863 88 207

98,655 81,151 28,220 15,370 20,223 8,099 4,680 2,582 1,557 205 215

96,788 84,833 32,652 18,797 14,807 8,352 4,963 2,482 2,038 533 209

Source: USEIA (2018c) with permission (17 U.S.C. §105).

renewable energy production in the United States will almost certainly increase even more drastically over the next decade. During the last few years, the States of Hawaii, California, Colorado, Maine, Nevada, New Mexico, New Jersey, New York, Washington, Connecticut, Rhode Island, and Virginia, including Washington, DC, and Puerto Rico, have either passed legislation or enacted executive orders committing to achieving 100% renewable or clean energy generation by 2050 (Podesta et al. 2019, Fields 2020). Washington, DC, and Rhode Island have devised the most ambitious renewable energy policy. Washington, DC, is striving to attain 100% renewable energy generation by 2032 (DC DEE 2019), and Rhode Island is determined to reach this goal by 2030 (Rhode Island Exec. Order No. 20-01, January 17, 2020). Virginia became the first Southern state in the nation to join this newly emerging carbon-free policy movement, mandating the development of a 9.0 × 1012 J/h (2,500 MW) offshore wind facility that will be completed by 2026 and establishing an additional 2.0 × 1013 J/h (5,500 MW) of onshore wind and solar energy by 2028 (Virginia Exec. Order No. 43, September 16, 2019). The US transition to 100% renewable energy utilization will hopefully become a reality in the imminent future.

SUMMARY The prolongation of the residential and commercial ITC, PTC, and MACRS is an essential requirement for expanding our nation’s renewable energy capabilities. Fortunately, there is bipartisan support for these policy measures in the 116th US Congress. Despite an over 100% increase in federal subsidies for the US solar (2013 to 2016) and wind (2010 to 2016) industries (USEIA 2018c), we still must

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significantly decrease the amount of subsidies for the development of new fossil fuel infrastructure and allocate additional federal funds to aid the renewable energy technology sector. Topics covered in the later chapters discuss the advantageous aspects of establishing micro-hydropower installations utilized for both remote and urban areas, the benefits of microbial fuel cells (MFCs) that transform wastewater into electricity, incorporating renewables in desalination technologies, and also the opportunity for providing energy generation from solar radiation and solar disinfection that provides wastewater treatment. This publication also includes the innovative process of anaerobic digestion of wastewater to produce biogas energy and the formation of decentralized green water-infrastructure systems, among other methods of sustainable renewable energy generation. Once additional states pass new laws to eliminate our reliance on fossil fuels, renewables will thrive, and the probability of encountering extreme weather events will diminish, safeguarding future generations of humankind from the unfavorable consequences of anthropogenic climate change. As stated previously in this chapter, “We must not be selfish or timid if we hope to have a decent world for our children and our grandchildren … By acting now we can control our future instead of letting the future control us…” (Carter 1977).

References 40 CFR Part 60, 80 FR, Vol. 80, No. 64661-65120. “Carbon pollution emissions guidelines for existing stationary sources: Electric utility generating units.” Federal Register. Accessed October 23, 2015. https://www.govinfo.gov/content/pkg/FR-2015-10-23/ pdf/2015-22842.pdf. 40 CFR Part 80, FR, Vol. 81, No. 238. “Renewable fuel standard program: Standards for 2017 and biomass-based diesel volume for 2018.” Federal Register. Accessed December 12, 2016. https://www.govinfo.gov/content/pkg/FR-2016-12-12/pdf/2016-28879.pdf ACEEE (American Council for an Energy-Efficient Economy). 2018. “State and local policy database.” Accessed April 4, 2019. https://database.aceee.org/state/massachusetts. British Petroleum. 2019. “BP statistical review of world energy.” 67th ed. Accessed April 27, 2019. https://www.bp.com/en/global/corporate/energy-economics/statistical-review-ofworld-energy.html. Carter, J. 1977. “Address to the nation on energy.” Univ. of Virginia, Miller Center, Presidential Speeches. Accessed March 2, 2019. https://millercenter.org/the-presidency/ presidential-speeches/april-18-1977-address-nation-energy. Collier, P., and A. J. Venables. 2014. “Closing coal: Economic and moral incentives.” Oxford Rev. Econ. Policy 30 (3): 492–512. CRS (Congressional Research Service). 2019. “Biomass: Comparison of definitions in legislation.” Accessed July 3, 2019. https://fas.org/sgp/crs/misc/R40529.pdf. DC DEE (DC Department of Energy and Environment). 2019. “Mayor Bowser signs historic clean energy bill, calling for 100% renewable electricity by 2032.” Accessed March 7, 2019. https://doee.​dc.gov/release/mayor-bowser-signs-his​toric-clean-ener​ gy-bill-calling-100-renewable-electricity-2032. DOE (United States Department of Energy). 2015. Unlocking our nation’s wind potential. Washington, DC: Office of Energy Efficiency & Renewable Energy.

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DOE. 2017a. “Q4 2016/Q1 2017 presentation—Solar industry update.” Solar Energy Technologies Office. Accessed April 4, 2019. https://www.energy.gov/eere/solar/ q4-2016q1-2017-presentation-solar-industry-update. DOE. 2017b. “U.S. energy and employment report.” Accessed April 8, 2019. https://www. energy.gov/downloads/2017-us-energy-and-employment-report. DOE. 2018. 2017 wind technologies market report. Washington, DC: Office of Energy Efficiency & Renewable Energy. Accessed March 5, 2019. https://www.energy.gov/sites/ prod/files/2018/08/f54/2017_wind_technologies_market_report_8.15.18.v2.pdf. DOE. 2019a. Ethanol fuel basics. Washington, DC: Office of Energy Efficiency & Renewable Energy. Accessed March 2, 2019. https://afdc.energy.gov/fuels/ethanol_fuel_basics. html. DOE. 2019b. Advantages and challenges of wind energy. Washington, DC: Office of Energy Efficiency & Renewable Energy. Accessed April 8, 2019. https://www.energy.gov/eere/ wind/advantages-and-challenges-wind-energy. EPA (Environmental Protection Agency). 2019a. “EPA finalizes affordable clean energy rule, ensuring reliable, diversified energy resources while protecting our environment.” News Release from Headquarters, Air and Radiation (OAR). Accessed June 21, 2019. https://www.epa.​gov/​newsreleases/epa-finalizes-affor​d able-clean-ene​ rgy-rule-ensuring-reliable-diversified-energy. EPA. 2019b. “Energy resources for state and local governments: State renewable energy resources.” Environmental Topics. Accessed April 4, 2019. https://www.epa.gov/ statelocalenergy/state-renewable-energy-resources#State Policies to Support Renewable Energy. Erickson, W. P., M. M. Wolfe, K. J. Bay, D. H. Johnson, and J. L. Gehring. 2014. “A comprehensive analysis of small-passerine fatalities from collision with turbines at wind energy facilities.” PLoS One 9 (9): e107491. Fang, X., X. Hu, G. Janssens-Maenhout, J. Wu, J. Han, S. Su, J. Zhang, and J. Hu. 2013. “Sulfur hexafluoride (SF6) emission estimates for China: An inventory for 1990–2010 and a projection to 2020.” Environ. Sci. Technol. 47 (8): 3848–3855. Fields, S. 2020. “100 percent renewable targets.” Energy Sage. Accessed June 15, 2020. https://news.energysage.com/states-with-100-renewable-targets/. GWEC (Global Wind Energy Council). 2015. “Wind in numbers.” Accessed March 17, 2019. http://www.gwec.net/globalfigures/windinnumbers/. H.R. 8444, 95th Congress. 1977–1978. “National Energy Act of 1978.” https://www. congress.gov/bill/95th-congress/house-bill/8444. H.R. 5263, 95th Congress. 1977–1978. “Energy Tax Act of 1978.” Pub. L. No. 95-618, 92 Stat. 3174. https://www.govtrack.us/congress/bills/95/hr5263/text. H.R. 1424, 110th Congress. 2008. “The Emergency Economic Stabilization Act of 2008.” Pub. L. No. 110-343, 122 Stat. 3765. https://www.congress.gov/110/plaws/publ343/ PLAW-110publ343.pdf. H.R. 2029, 114th Congress. 2015–2016. “Consolidated Appropriations Act of 2016.” Pub. L. No. 114-113, 129 Stat. 2424. https://www.congress.gov/114/plaws/publ113/PLAW114publ113.pdf. H.R. 1, 115th Congress. 2017. “The Tax Cuts and Jobs Act of 2017.” Pub. L. No. 115-97, 131 Stat. 2054. https://www.congress.gov/115/bills/hr1/BILLS-115hr1enr.pdf. H.R. 1892, 115th Congress. 2017–2018. “Bipartisan Budget Act of 2018.” Pub. L. No. 115123. https://www.congress.gov/115/plaws/publ123/PLAW-115publ123.pdf H.R. 3301, 116th Congress. 2019–2020. “Taxpayer Certainty and Disaster Tax Relief Act of 2019.” https://www.congress.gov/bill/116th-congress/house-bill/3301.

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IPCC (International Panel on Climate Change). 2014. “Climate change 2014: Synthesis report.” Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. https://ar5-syr.ipcc.ch/. JAXA (Japan Aerospace Exploration Agency). 2019. “Whole-atmosphere monthly mean CO2 concentration based on GOSAT observations.” Accessed March 17, 2019. http:// www.gosat.nies.go.jp/en/recent-global-co2.html. 547. KY-NREPC (Kentucky Natural Resources and Environmental Protection Cabinet). 2019. “Dissolved oxygen and water quality.” State of Kentucky. Accessed May 4, 2019. http:// www.state.ky.us/nrepc/water/ramp/rmdo2.htm. Lazarus, M., P. Erickson, and K. Tempest. 2015. Supply-side climate policy: The road less taken. Stockholm Environment Institute. Accessed April 1, 2019. https://mediamanager. sei.org/documents/Publications/Climate/SEI-WP-2015-13-Supply-side-climate-policy. pdf. MA-DER (Massachusetts Department of Energy Resources). 2019a. Leading by example initiatives. MA-DER. Accessed April 6, 2019. https://www.mass.gov/service-details/ leading-by-example-initiatives#transportation. MA-DER. 2019b. Renewable energy snapshot. Massachusetts Department of Energy Resources. Accessed April 6, 2019. https://www.mass.gov/info-details/renew​able-ene​ rgy-snapshot. Mass. (MA-USA) Exec. Order No. 484, April 18, 2007 https://www.mass.gov/files/ documents/2016/08/od/eo484.pdf. McDermott, J. 2019. “Offshore wind developers to invest $4.5M in Rhode Island.” Phys. org. Accessed May 7, 2019. https://phys.org/news/2019-04-offshore-invest-45m-rhodeisland.html. McDonald, R. I., J. D. Olden, J. J. Opperman, W. M. Miller, J. Fargione, C. Revenga, et al. 2012. “Energy, water and fish: Biodiversity impacts of energy-sector water demand in the United States depend on efficiency and policy measures.” PLoS One 7 (11): e50219. NCSL (National Conference of State Legislators). 2019. “State renewable portfolio standards and goals.” Accessed April 4, 2019. http://www.ncsl.org/research/energy/ renewable-portfolio-standards.aspx. Niklitschek, E. J., and D. H. Secor. 2009. “Dissolved oxygen, temperature and salinity effects on the ecophysiology and survival of juvenile Atlantic Sturgeon in estuarine waters: I. Laboratory results. model development and testing.” J. Exp. Mar. Biol. Ecol. 381 (Supp-S): S150–S160. Pandey, B., and A. Karki. 2017. Hydroelectric energy: Renewable energy and the environment. Boca Raton, FL: CRC Press, Taylor & Francis. Podesta, J., C. Goldfuss, T. Higgins, B. Bhattacharyya, A. Yu, and K. Costa. 2019. State fact sheet: A 100 percent clean future. Washington, DC: Center for American Progress. Rhode Island (USA) Exec. Order No. 20-01, January 17, 2020. https://governor.ri.gov/ documents/orders/Executive-Order-20-01.pdf. S. 426, 99th Congress. 1985–1986. “Electric Consumers Protection Act of 1986.” Pub. L. No. 99-495, 100 Stat. 1243. https://www.congress.gov/bill/99th-congress/senate-bill/426. S. 2289, 116th Congress. 2019–2020. “Renewable Energy Extension Act of 2019.” https:// www.congress.gov/bill/116th-congress/senate-bill/2289/text. SEIA (Solar Energy Industries Association). 2019. Solar investment tax credit (ITC). Washington, DC: SEIA. Shrimali, G., M. Lynes, and J. Indvik. 2015. “Wind energy deployment in the U.S.: An empirical analysis of the role of federal and state policies.” Renewable Sustainable Energy Rev. 43 (C): 796–806.

US Renewable Energy Policy—Analysis and Recommendations

15

Stamford, L., and A. Azapagic. 2014. “Life cycle environmental impacts of UK shale gas.” Appl. Energy 134 (1): 506–518. Stoklosa, A. M., D. H. Keller, R. Marano, and R. J. Horwitz. 2018. A review of dissolved oxygen requirements for key sensitive species in the Delaware estuary. Philadelphia: Academy of Natural Sciences of Drexel Univ. Than, K. 2018. Critical minerals scarcity could threaten renewable energy future. Stanford, CA: Stanford Univ., School of Earth, Energy & Environmental Sciences. Unger, D. J. 2016. “America now has 27.2 gigawatts of solar energy: What does that mean?” Inside Climate News. Accessed April 4, 2019. https://insideclimatenews.org/ news/24052016/solar-energy-27-gigawatts-united-states-one-million-rooftop-panelsclimate-change-china-germany. USEIA (United States Energy Information Administration). 2016. “Annual energy outlook 2016.” Accessed April 1, 2019. https://www.eia.gov/outlooks/archive/aeo16/ mt_naturalgas.php#natgasprod_exp. USEIA. 2018a. Petroleum, natural gas, and coal still dominate U.S. energy consumption. Washington, DC: Office of Energy Efficiency & Renewable Energy. Accessed April 5, 2019. https://www.eia.gov/todayinenergy/detail.php?id=36612. USEIA. 2018b. “The United States is now the largest global crude oil producer.” Independent Statistics & Analysis. Accessed April 27, 2019. https://www.eia.gov/todayinenergy/ detail.php?id=37053. USEIA. 2018c. “Direct federal financial interventions and subsides in energy in fiscal year 2016.” Independent Statistics & Analysis. Accessed May 16, 2019. https://www.eia.gov/ analysis/requests/subsidy/. USEIA. 2019a. “What is U.S. electricity generation by energy source?” Independent Statistics & Analysis. Accessed April 16, 2019. https://www.eia.gov/tools/faqs/faq. php?id=427&t=3. USEIA. 2019b. “Biofuels: Ethanol and biodiesel explained, ethanol and the environment.” Independent Statistics & Analysis. Accessed April 5, 2019. https://www.eia.gov/ energyexplained/index.php?page=biofuel_ethanol_environment. USEIA. 2019c. “Wind explained, where wind power is harnessed.” Independent Statistics & Analysis. Accessed April 5, 2019. https://www.eia.gov/energyexplained/index. php?page=wind_where. USEIA. 2019d. “U.S. renewable electricity generation has doubled since 2008.” Independent Statistics & Analysis. Accessed April 16, 2019. https://www.eia.gov/todayinenergy/ detail.php?id=38752. UTIA (University of Tennessee Institute of Agriculture). 2019. “The Sun’s energy.” Solar and Sustainable Energy. Accessed May 4, 2019. https://ag.tennessee.edu/solar/Pages/ What%20Is%20Solar%20Energy/Sun%27s%20Energy.aspx. Virginia (USA) Exec. Order No. 43, September 16, 2019. https://www.governor.virginia. gov/media/governorvirginiagov/executive-actions/EO-43-Expanding-Access-toClean-Energy-and-Growing-the-Clean-Energy-Jobs-of-the-Future.pdf. Wang, J. F., and N. Muller. 2012b. “Performance prediction of array arrangement on ducted composite material marine current turbines (CMMCTs).” Ocean Eng. 41: 21–26. Wang, J. F., J. Piechna, and N. Muller. 2012a. “A novel design of composite water turbine using CFD.” J. Hydrodyn. 24 (1): 11–16. WNA (World Nuclear Association) 2011. Comparison of lifecycle greenhouse gas emissions of various electricity generation sources. WNA Rep. Accessed April 3, 2019. http://www. worldnuclear.org/uploadedFiles/org/WNA/Publications/Working_Group_Reports/ comparison_of_lifecycle.pdf.

CHAPTER 2

Renewables and Regulatory Requirements of the United States S. Rao Chitikela

INTRODUCTION Renewable energy (RE) is that gets renewed in an inexhaustible way on Planet Earth. The RE sources include (but not limited to) solar, wind, biofuels, geothermal, tidal wave, hydroelectric, and the anthropogenic landfill gas (LFG). RE generation and meeting the sustainability requirements is currently the preferred choice of power generation in the United States and worldwide. The United States has successfully embarked on incorporating renewables to a significant level into the applicable statewide energy mix in generation and distribution, via the use of effective energy policy and rulemaking. In the United States (and worldwide), RE policies have been developed and implemented with standards to go with and financial incentives—grants, loans, rebates, and tax incentives. RE systems are (considered to be) environmentally friendly compared to the fossil fuel-fired electric systems, could be a preferred distributed system in a geographical area, and play a significant role in the avoidance or current control of greenhouse gases (GHGs) worldwide. These RE resources would include (notlimited-to) solar photovoltaic (PV) or solar thermal; wind; biogas-to-energy CHP (where CHP is combined heat and power); landfill gas (LFG) CHP; hydroelectricpower (hydel); geothermal (open- or closed-loop system); biomass; fuel cells, including the microbial fuel cells (MFCs); and water wave. Net metering of power usage is possible when RE systems are taken advantage of at the residential, commercial, or municipal level, where the electricity billing would be based on customer’s usage or return of power, from or to the grid. In the United States, the Federal Energy Regulatory Commission (FERC) has the authority and the jurisdiction over interstate and wholesale electric commerce and NO jurisdiction over the local distribution of electricity, retail sales, siting, 17

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Renewable Energy Technologies and Water Infrastructure

construction, environmental matters, and safety requirements, as reported (NREL 2016). The North American Electric Reliability Corporation (NERC) oversees the reliability of the bulk electric system, where it verifies the system reliability and standards’ development and enforcement. The independent system operators (ISOs) and regional transmission operators (RTOs) are identified and utilized to operate the electrical system under FERC; the electric-grid areas not under an ISO or RTO are operated by the investor-owned utilities (IOUs), municipal (cooperatives), or the Federal Power Marketing Administrations. In all, the balancing authorities—responsible for integrating resource plans, maintaining balance of generation and load within its area, and supporting interconnection frequency in real time—and ISOs and RTOs are required to be in compliance with reliability standards of NERC. Thus, various federal, state, and local regulatory requirements on RE resources and systems are elucidated (to the extent feasible) in the following sections. The global development and operation of renewables is at 23.9% of the electricity generation and is projected to increase to 29.4% by 2023. Globally, the electricity accounts for a fifth of energy consumption and, so, a rapid application and usage of renewables in the transportation and heating sectors is required (IEA 2019). Renewable energy production and consumption of the United States since the year 2000 is shown in Figure 2-1. The total renewable energy consumption has been (more than) approximately 9,488 quadrillion J (9.0 quadrillion Btu) in the United States (USEIA 2019). As seen in Figure 2-1, the types of renewables included are hydroelectric, geothermal, solar, wind, wood-biomass, ethanol, biodiesel, and waste biomass; a Btu is approximately 1,054.2 J and can be used for unit conversion.

Figure 2-1.  US’ renewable energy—production and consumption. Source: USEIA (2019).

Renewables and Regulatory Requirements of the United States

19

US-CODE, LAW, AND ACT—RENEWABLE ENERGY The “US Title 42—The Public Health and Welfare, Chapter 125—Renewable Energy and Energy Efficiency Technology Competitiveness,” includes the Congress-finding, national goals for renewable energy, and energy efficiency authorizations. Under the 42USC, §12001, the Congress finds “… it is in the national security and economic interest of the United States to foster greater efficiency in the use of available energy supplies and greater use of renewable energy technologies.” In addition, the purpose is “… to pursue an aggressive national program of research, development, demonstration, and commercial application of renewable energy and energy efficiency technologies in order to ensure a stable and secure future energy supply …” The national goals (and the multiyear funding, on selected REs) for wind, PV, solar thermal, alcohol from biomass, biofuel energy systems, biodiesel energy systems, hydrogen energy systems, solar building energy systems, ocean energy systems, geothermal energy systems, low head hydro, and energy storage systems are specified in the 42USC, §12003. The RE project technologies are included in 42USC, §12005(c)(2): Projects under this section may include the following technologies: 1. Conversion of cellulosic biomass to liquid fuels. 2. Ethanol and ethanol by-product processes. 3. Direct combustion or gasification of biomass. 4. Biofuel energy systems. 5. Photovoltaics, including utility scale and remote applications. 6. Solar thermal, including solar water heating. 7. Wind energy. 8. High-temperature and low-temperature geothermal energy. 9. Fuel cells, including transportation and stationary applications. 10. Nondefense high-temperature superconducting electricity technology. 11. Source reduction technology. 12. Factory-made housing. 13. Advanced district cooling. where the term “source reduction” means [as included in 42USC, §12002(5)] any practice which reduces the amount of any hazardous substance, pollutant, or contaminant entering any waste stream or otherwise released into the environment, including fugitive emissions, prior to recycling, treatment, or disposal; and reduces the hazards posed to the public health and the environment associated with the release of such substances, pollutants, or contaminants, including equipment or technology modifications, process or procedure modifications, reformulation

20

Renewable Energy Technologies and Water Infrastructure

or redesign of products, substitution of raw materials, and improvements in housekeeping, maintenance, training, and inventory control but not including any practice that alters the physical, chemical, or biological characteristics or the volume of a hazardous substance, pollutant, or contaminant through a process or activity which itself is not integral to and necessary for the manufacture of a product or providing a service (42USC 2019a). The Energy Policy requirements are included in the 42USC, Chapter 134, §13201 to 13574; Subchapter V includes the applicable requirements of Renewable Energy, §13311 to 13317, that explains the renewable energy export technology training; renewable energy advancement awards; study of tax and rate treatment of renewable energy projects; data system and energy technology evaluation; innovative renewable energy technology transfer program; and renewable energy production incentive. The “42USC, Chapter 149—National Energy Policy and Programs, Subchapter II—Renewable Energy,” §15851, includes that the RE Resource Assessment be conducted—“Secretary (of the Department) shall review the available assessments of renewable energy resources within the United States, including solar, wind, biomass, ocean (including tidal, wave, current, and thermal), geothermal, and hydroelectric energy resources, and undertake new assessments as necessary, taking into account changes in market conditions, available technologies, and other relevant factors” and the reports be published (42USC 2019b). The Energy Policy Act of 2005 (enacted January 4, 2005) includes Title II— Renewable Energy; Title VIII—Hydrogen; Title IX—Research and Development, Subtitle C—Renewable Energy; Title XIII—Energy Policy Tax Incentives; Title XVI—Climate Change; and Title XVIII—Studies, to list a few relevant to further review of this enacted law-text (US-Congress 2005).

RENEWABLE ENERGY STANDARDS The renewable energy standards (RES) or the renewable portfolio standards (RPS) are adopted and established by the states, where the applicable requirements vary state-to-state. It is envisaged that at 20% or more of the electric-suite, the application-of or drawing energy via use of renewables would be significant in that it supports a good control of air pollution (otherwise, facing the air pollution due to 100% firing of fossil fuels). Thus, RE credits or certificates (RECs) are also included under the RE regulations. This US renewable energy market has been estimated at $US 64 billion. Table 2-1 shows the US legislation(s) on accomplishment of renewables (NCSL 2019). The procurement of renewable energy is critical in identifying various elements of capital expenditure (CapEx), operational expenditure (OpEx), and operation and maintenance (O&M) and in working with the stakeholders on a long-term basis. The significant participants and elements are as follows: the

2004

1998

2005 2001

2001 (voluntary target); 2007 (standard). 2011 1983

Arizona California

Colorado

Connecticut

Delaware Hawaii

Illinois

Kansas

2009 (standard); 2015 (goal).

2009–2010 Legislative session 2006 2002

Alaska

Indiana Iowa

Year established

State

10% by 2025 105 MW of generating capacity for IOUs (investor-owned utility) 15% by 2015–2019; 20% by 2020

25% by 2025–2026 30% by 2020; 40% by 2030; 70% by 2040; 100% by 2045 25% by 2025–2026

30% by 2020 (IOUs); 10% or 20% for municipalities and electric cooperatives depending on size 44% by 2030 (the State website shows 48%)

the state receive 50% of its electrical generation from renewable energy sources by 2025 15% by 2025 44% by 2024; 52% by 2027; 60% by 2030, and also requires 100% clean energy by 2045

Renewable energy requirement

Table 2-1.  The United States’ Renewable Portfolio or Energy Standards and Goals.

(Continued)

Kan Stat. Ann. §66-1256 et seq.; Goal: Senate Bill 91

Conn. Gen. Stat. §16-245a et seq.; Conn. Gen. Stat. §16-1; Senate Bill 9 (2018) Del. Code Ann. 26 §351 et seq. Hawaii Rev. Stat. §269-91 et seq.; House Bill 623 (2015) Ill. Rev. Stat. ch. 20 §688 (2001); Ill. Rev. Stat. ch. 20 §3855/1-75 (2007); Senate Bill 2814 (2016) Ind. Code §8-1-37 Iowa Code §476.41 et seq.

“Ariz. Admin. Code §14-2-1801 et seq.” “Cal. Public Utilities Code §399.11 et seq.; Cal. Public Resources Code §25740 et seq.; Assembly Bill 327 (2013); Senate Bill 350 (2015); Senate Bill 100 (2018).” Colo. Rev. Stat. §40-2-124; Senate Bill 252 (2013)

House Bill 306

Statute, code, or order Renewables and Regulatory Requirements of the United States

21

Class I (new sources): 35% by 2030 and an additional 1% each year after. Class II: 6.7% by 2020 15% by 2021 (standard), 35% by 2025 (goal, including energy efficiency and demand reduction) 26.5% by 2025 (IOUs), 25% by 2025 (other utilities) 15% by 2021 (IOUs) 15% by 2015 25% by 2025 25.2% by 2025 50% by 2030

2004

1997

2007

2007

2007 2005 1997 2007

1991

2002

Maryland

Massachusetts

Michigan

Minnesota

Missouri Montana Nevada New Hampshire New Jersey

New Mexico

20% by 2020 (IOUs); 10% by 2020 (co-ops)

25% by 2020

40% by 2017

1999

Maine

Renewable energy requirement

Year established

State

Statute, code, or order

(Continued)

N.J. Rev. Stat. §48:3-49 et seq.; Assembly Bill 3723 (2018) N.M. Stat. Ann. §62-15; N.M. Stat. Ann. §62-16

Mo. Rev. Stat. §393.1020 et seq Mont. Code Ann. §69-3-2001 et seq. Nev. Rev. Stat. §704.7801 et seq. N.H. Rev. Stat. Ann. §362-F

Minn. Stat. §216B.1691

Mich. Comp. Laws §460.1001 et seq.; Senate Bill 438 (2016)

Me. Rev. Stat. Ann. 35-A §3210 et seq.; Me. Rev. Stat. Ann. 35-A §3401 et seq. (wind energy) Md. Public Utilities Code Ann. §7-701 et seq.; Senate Bill 921; House Bill 1106 (2016 enrolled, 2017 veto override) Mass. Gen. Laws Ann. ch. 25A §11F; House Bill 4857 (2018)

Table 2-1.  The United States’ Renewable Portfolio or Energy Standards and Goals. (Continued)

22 Renewable Energy Technologies and Water Infrastructure

2004

2007

2007 2008

2010 2007

2004 2004

2014 2008

North Carolina

North Dakota Ohio

Oklahoma Oregon

Pennsylvania Rhode Island

South Carolina South Dakota

Year established

New York

State

2% by 2021 10% by 2015

12.5% by 2021 (IOUs); 10% by 2018 (munis and coops) 10% by 2015 12.5% by 2026. Senate Bill 310 (2014) created a 2-year freeze on the state’s standard while a panel studied the costs and benefits of the requirement. The freeze was not extended in 2016 15% by 2015 25% by 2025 (utilities with 3% or more of the state’s load); 50% by 2040 (utilities with 3% or more of the state’s load); 10% by 2025 (utilities with 1.5%–3% of the state’s load); 5% by 2025 (utilities with less than 1.5% of the state’s load) 18% by 2020–2021 14.5% by 2019, with increases of 1.5% each year until 38.5% by 2035.

50% by 2030

Renewable energy requirement

Statute, code, or order

(Continued)

Pa. Cons. Stat. tit. 66 §2814 R.I. Gen. Laws §39-26-1 et seq.; R.I. Gen. Laws §39-26.1 et seq. (contracting standard); House Bill 7413a (2016) House Bill 1189 S.D. Codified Laws Ann. §49-34A-94; S.D. Codified Laws Ann. §49-34A-101 et seq.

Okla. Stat. tit. 17 §801.1 et seq. Or. Rev. Stat. §469a; Senate Bill 1547 (2016)

N.D. Cent. Code §49-02-24 et seq. Ohio Rev. Code Ann. §4928.64 et seq.

NY PSC Order Case 03-E-0188; 2015 New York State Energy Plan. N.C. Gen. Stat. §62-133.8

Table 2-1.  The United States’ Renewable Portfolio or Energy Standards and Goals. (Continued) Renewables and Regulatory Requirements of the United States

23

15% by 2025 15% by 2020 10% from 2015 to 2019, 15% from 2020 to 2024, 25% by 2025 10% by 2015 20% by 2020, 100% by 2032 25% by 2035 20% by 2016

2005 (voluntary target); 2015 (standard) 2007 2006

Established: 2009; Repealed 2015 1998 2005

2008 2007; goal reduced in 2014 2010 2009

Vermont

Source: NCSL (2019).

Wisconsin Washington, DC Guam Northern Mariana Islands Puerto Rico US Virgin Islands

West Virginia

Virginia Washington

2008

Utah

20% by 2035 20% by 2015; 25% by 2020; 30% by 2025; up to 51% after 2025

55% by 2017; 75% by 2032

5,880 MW by 2015. 10,000 MW by 2025 (goal; achieved) 20% by 2025

1999

Texas

Renewable energy requirement

Year established

State

Statute, code, or order

PR S 1519 (2010); PR H 2610 (2010) VI B 9 (2009)

Va. Code §56-585.2 Wash. Rev. Code §19.285; Wash. Admin. Code §480-109; Wash Admin. Code §194-37 W. Va. Code §24-2F; Repeal: House Bill 2001 Wisc. Stat. §196.378 D.C. Code §34-1431 et seq., Bill 650 (2016); Bill 904 (2018) Guam Public Law §29-62 N. M. I. Public Law §15-23; House Bill 165 (2014)

Utah Code Ann. §54-17-101 et seq.; Utah Code Ann. §10-19-101 et seq. Vt. Stat. Ann. tit. 30 §8001 et seq.; Standard: House Bill 40

Tex. Utilities Code Ann. §39.904

Table 2-1.  The United States’ Renewable Portfolio or Energy Standards and Goals. (Continued)

24 Renewable Energy Technologies and Water Infrastructure

Renewables and Regulatory Requirements of the United States

25

public utility commission (PUC)—A regulatory body that oversees regulation of rates and services of a public utility. It can also be referred to as a utilities commission, utility regulatory commission, or public service commission; an independent power producer (IPP) would be “A corporation, person, agency, authority, other legal entity or instrumentality that owns or operates facilities for the generation of electricity for use primarily by the public, and that is not an electric utility”; a power purchase agreement (PPA) would be “A financial mechanism through which a bulk electricity customer enters into a long-term electricity supply contract with an IPP. The contract defines all the terms and conditions of the transaction of electricity sales between the supplier and buyer, including dates of commencement and termination, terms of payment, schedule for delivery, penalties, and exclusions.” In addition, the variable renewable energy (VRE) generator—a renewable electricity generator, such as wind and or solar power plants—provides variable and no dispatchable power output owing to the natural variability of the energy resource. The integration of renewable energy resources or the infrastructure to the existing power grid has also been evolved via restructuring the wholesale and retail electricity markets. “Restructured wholesale markets comprise a range of different market-based approaches to balancing bulk power supply and demand while creating an institutional separation between transmission operations and generation. Retail restructuring refers to the introduction of consumer choice among competing suppliers of enduse electric services” (NREL 2016).

RENEWABLE PORTFOLIO STANDARDS—THE STATE OF CONNECTICUT, EXAMPLE The State of Connecticut uses the RPS policy that requires the electric providers to annually maintain a “specified percentage or amount of the energy they generate or sell from renewable sources.” One renewable energy certificate (REC) for each of 3.6 × 109 J (1 MWh) of electricity produced will be issued to the qualified electric providers. The qualified renewables are categorized into three classes— Class I, Class II, or Class III. The regulatory information on Classes I, II, and III, and the “‘required Annual Renewable Energy Percentages” with respect to the said classes are, as follows (CT-PURA 2019): Class I renewable energy source, as defined in §16-1(a)(20) of the General Statutes of Connecticut (Conn. Gen. Stat.), means electricity derived from: solar power; wind power; fuel cell; geothermal; landfill methane gas, anaerobic digestion or other biogas derived from biological sources; thermal electric direct energy conversion from a certified Class I renewable energy source; ocean thermal power; wave or tidal power; low-emission advanced renewable energy conversion technologies, including, but not limited to, zero emission low-grade heat power generation systems based on organic oil-free rankine, kalina, or

26

Renewable Energy Technologies and Water Infrastructure

similar “nonstream” (nonsteam) cycles that use waste heat from an industrial or commercial process that does not generate electricity; run-of-the-river hydropower facility that began operation after July 1, 2003, and has a generating capacity of not more than 30 MW, or a run-of-the-river hydropower facility that received a new license after January 1, 2018, under the FERC rules pursuant to 18 CFR 16, as amended from time to time, and provided the facility is not based on a new dam or a dam identified as a candidate for removal; and biomass facility that uses sustainable biomass fuel, as defined in Conn. Gen. Stat. §16-1(a)(39) (cultivated and harvested in a sustainable manner). “Sustainable biomass fuel” does not mean construction and demolition waste, finished biomass products from sawmills, paper mills, or stud mills; organic refuse fuel derived separately from municipal solid waste (MSW); or biomass from old growth timber stands, except where (1) such biomass is used in a biomass gasification plant that received funding prior to May 1, 2006, from the Clean Energy Fund established pursuant to Section 16-245n, or (2) the energy derived from such biomass is subject to a long-term power purchase contract pursuant to Subdivision (2) of Subsection (j) of Section 16-244c entered into prior to May 1, 2006) and meets certain emissions requirements; and any electrical generation, including distributed generation, generated from a Class I renewable energy source, provided, on and after January 1, 2014, any megawatt hours that are claimed or counted toward compliance in another province or state, other than Connecticut, shall not be eligible. Class II renewable energy source, as defined in Conn. Gen. Stat. §16-1(a) (21), means electricity derived from a trash-to-energy facility that has obtained a permit pursuant to Section 22a-208a and Section 22a-174-33 of the regulations of Connecticut state agencies. Class III source, as defined in Conn. Gen. Stat. §16-1(a)(38), means • Electricity output from combined heat and power systems with a minimum operating efficiency of 50% that are part of customer-side distributed resources developed at commercial and industrial facilities in Connecticut on or after January 1, 2006; • Waste heat recovery systems installed on or after April 1, 2007, that produces electrical or thermal energy by capturing preexisting waste heat or pressure from industrial or commercial processes; • Electricity savings from conservation and load management programs that started on or after January 1, 2006 (on and after January 1, 2014, programs supported by ratepayers are not eligible); and • Any demand-side management project awarded a contract pursuant to §16-243 m (eligibility is based on the term of the contract). Table 2-2 shows the State of Connecticut requirements of Classes I, II, and III renewable energy contributions on an annual basis, since 2018 and up to 2030.

Renewables and Regulatory Requirements of the United States

27

Table 2-2.  Required, Annual Renewable Energy Percentages. Year

Class I (%)

Class II or Class I (add’l) (%)

Class III (%)

Total (%)

2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030

17.0 19.5 21.0 22.5 24 26 28 30 32 34 36 38 40

4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0

4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0 4.0

25.0 27.5 29.0 30.5 32 34 36 38 40 42 44 46 48

Note: As shown, the Class I renewables’ requirement is projected to 40%, while the Classes II and III requirements are no change at 4% each, by Year 2030 in the State of Connecticut.

RENEWABLE PORTFOLIO STANDARDS ELIGIBILITY—THE STATE OF CALIFORNIA, EXAMPLE The eligible electric generation facilities will be included in the RPS procurement process and, thus, provided with the RPS Certification. Therefore, to qualify for the RPS Certification, the eligible electric-generating facilities need to use one or more RE resources that meeting the resource-specific requirements. The CA Energy Commission publishes the RPS Eligibility Guidebook that must be followed by the applicants for RPS Certification. Chapter 2 of the Guidebook provides the RE resources and the eligibility criteria in the State of California, and the RE resource type and eligibility are as follows (for complete details, verify the CA Energy Commission’s regulatory requirements) (Green and Crume 2017): Biodiesel: “A facility may qualify for RPS certification if it generates electricity using biodiesel derived from biomass feedstock or from an eligible solid waste conversion process using municipal solid waste. Biomass: “A facility may qualify for RPS certification if it generates electricity using a biomass fuel.” A fuel that is resulting from “biomass conversion” is inclusive. Biomethane: “A facility may qualify for RPS certification if it generates electricity using biomethane derived from digester gas and/or landfill gas.

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Biomethane may be used to generate electricity at a facility that receives the biomethane in one of four ways: (1) onsite generating facility using a dedicated pipeline; (2) offsite generating facility using a dedicated pipeline; (3) offsite generating facility using a fuel container; and (4) offsite generating facility using a common carrier pipeline. Fuel cell using renewable fuel: “A facility that uses a fuel cell conversion technology may qualify for RPS certification if the facility uses either an RPS-eligible renewable energy resource, qualifying hydrogen gas, or both. Geothermal: “A facility may qualify for RPS certification if it generates electricity using a geothermal resource. Only natural heat from within the earth that is captured for electric power production may be used to create RPS-eligible geothermal generation.” Hydroelectric: “The following types of hydroelectric facilities may be RPS eligible: (1) Small hydroelectric facilities 30 MW or less. (2) Conduit hydroelectric facilities 30 MW or less. (3) Hydroelectric generation units 40 MW or less and operated as part of a water supply or conveyance system. (4) Incremental hydroelectric facilities. Municipal solid waste: “A facility may qualify for RPS certification if it generates electricity using municipal solid waste (MSW) in either a combustion or conversion process…” Ocean thermal: “A facility may qualify for RPS certification if it generates electricity using an ocean thermal resource, such as the temperature differences between deep and surface ocean water.” Ocean wave: “A facility may qualify for RPS certification if it generates electricity using an ocean wave.” Solar: “A facility may qualify for RPS certification if it generates electricity using either a photovoltaic or solar thermal process to produce electricity.” Tidal current: “A facility may qualify for RPS certification if it generates electricity using a tidal current.” Wind: “A facility may qualify for RPS certification if it generates electricity using a wind resource. Facilities using wind resources can use any method to capture the naturally occurring wind, convert it to mechanical energy, and then generate electricity.”

LOCAL GOVERNMENT ON RENEWABLE ENERGY PROJECTS—STATE OF VIRGINIA, EXAMPLE The local governments must also include the responsibilities in the development, installation, and operation of RE projects.

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In the State of Virginia (VA), the Local Government Outreach Stakeholder Group (LOG) holds the main responsibility of siting the RE projects. Thus, with the guidance of LOG, VA developed model ordinances for wind and solar RE projects in the state. For example, the Model Utility Scale Wind Ordinance (dated April 4, 2012) includes purpose; applicability; definitions; type of permitting; applications and procedures, location, appearance, and operation of a project site; safety and construction; and decommissioning (VA-RE 2019): The “purpose”2 statement, as follows—The purpose of this ordinance is to provide for the siting, development, and decommissioning of utility-scale wind energy projects in [locality], subject to reasonable conditions that promote and protect the public health, safety and welfare of the community while promoting development of renewable energy resources.3 Purpose. The statement of purpose is based on similar provisions found in existing ordinances and models and was acceptable to most LOG members. The phrase “promoting development of renewable energy sources” conforms with Virginia’s Energy Policy (specifically, §67-103 of the Code of Virginia). The legal requirements of this Energy Policy are discussed in the companion document, “Introduction: DEQ’s Local Government Outreach for Renewable Energy,” which appears on DEQ’s website along with this model ordinance. One LOG member believed that including the promotion of renewable energy as part of the Purpose was going further than necessary. However, a local government chooses to articulate the Purpose of its wind ordinance, it should keep in mind the statutory mandate, incumbent on both local and state government entities, to promote the development of renewable energy. 2

Public Health, Safety, and Welfare. This model ordinance addresses local governments’ traditional areas of responsibility—public health, safety, and welfare—as they relate to wind energy projects. The model ordinance does not address protection of natural resources. In Virginia, the Department of Environmental Quality (DEQ) regulates impacts of wind projects on wildlife and historic resources pursuant to 9VAC15-40. The Virginia legislature delegated this authority to DEQ pursuant to the Small Renewable Energy Projects Act of 2009 (§10.1-1197.5 et seq. of the Code of Virginia). Other natural resources are regulated via permits administered by DEQ and other agencies or levels of government (e.g., air, water, waste, erosion and sediment control) pursuant to other state or federal laws. 3

A few critical terms of definitions are important in understanding and interpreting a law, policy and/or regulation(s), as follows (and included in the model-ordinance): “Applicant” means the owner or operator who submits an application to the locality for a permit to install a wind energy project under this ordinance.

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“Landowner” means the person who owns all or a portion of the real property on which a wind energy project is constructed. “Operator” means the person responsible for the overall operation and management of a wind energy project. “Owner” means the person who owns all or a portion of a wind energy project. “Rated capacity” means the maximum capacity of a wind energy project based on the sum total of each turbine’s nameplate capacity. The nameplate capacity is typically specified by the manufacturer with a label on the turbine equipment. “Wind energy project, utility-scale”4 means a facility that generates electricity from wind, and consists of (1) one or more wind turbines and other accessory structures and buildings, including substations, post-construction meteorological towers, electrical infrastructure, and other appurtenant structures and facilities within the boundaries of the site, and (2) is designed for, or capable of, operation at a rated capacity greater than 5-MW.5 Two or more wind turbines otherwise spatially separated but under common ownership or operational control, which are connected to the electrical grid under a single interconnection agreement, shall be considered a single utility-scale wind energy project. Definition of “Project.” In land use zoning and ordinances, one of the first issues is how to name and define wind energy installations. Commonly used terms include windmills, turbines, wind energy facilities, wind energy systems, and wind energy conversion systems. Although several planning experts recommended using the term facility, LOG members recommended using project wherever the term would fit, in order to be consistent with Virginia’s Small Renewable Energy Projects Act of 2009 (hereinafter “2009 statute”). 4

Rated Capacity of Utility-Scale Wind Project. This model ordinance utilizes “greater than 5 MW” to define the size project addressed by utility-scale wind projects in order to coordinate with the 2009 statute; however, local governments may wish to alter this number. One alternative mentioned was “>5 MW or 2 or more turbines.” In determining how to define the project sizes addressed by a utility-scale ordinance, local governments may want to keep in mind the tiers or levels of rated capacity that could be addressed in community-scale ordinances. The LOG is also framing a model wind ordinance for community-scale projects. 5

“Wind turbine” means a wind energy conversion system that converts wind energy into electricity through the use of a wind turbine generator that typically consists of a tower, nacelle, rotor, blades, controller and associated mechanical and electrical conversion components.

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The types of permitting can be based on—by right or permitted use, accessory uses, special exception/conditional use/special use permitting. The application and procedures would include: project description, site plan, documentation of right to use property for the proposed project, decommissioning plan, liability insurance, etc. The location, appearance, and operation of a project site would include: visual appearance, visual impacts, lighting, signage, noise, shadow flicker, height, setbacks, use of public roads, etc. The safety and construction would include: design, climb prevention/ locks, warnings, ground clearance, speed controls and brakes, emergency response plan, signal interference, construction and installation, etc. The decommissioning details would include: decommissioning plan, discontinuation or abandonment of project, surety, etc. Thus, VA has developed model ordinances for community-scale wind, residential-scale wind, research studies and other resources, evaluating sources on wind energy, larger and smaller scale solar model(s), and solar tax exemption model (VA-RE 2019).

 SOLAR AND WIND ENERGY RULE—BUREAU OF LAND MANAGEMENT The BLM under the US Department of Interior enacted the Solar and Wind Energy Rule via the amendment of Title V (Rights-of-Way) of the Federal Land Policy and Management Act (FLPMA), where the regulatory requirements are included in the Code of Federal Regulations (CFR), under Title 43, Public Lands: Interior—the 43CFR, Part 2800—Rights-of-Way under the Federal Land Policy and management Act (43CFR 2019). The Right-of-Way is defined under the act— “includes an easement, lease, permit, or license to occupy, use, or traverse public lands granted for the purpose listed in title V of this Act” (DOI/BLM 2016). A few definitions of terms relevant to RE development under this Rule 43CFR, Part 2800, §2801.5 are as follows: Designated leasing area means a parcel of land with specific boundaries identified by the BLM land use planning process as being a preferred location for solar or wind energy development that may be offered competitively. Megawatt (MW) capacity fee means the fee paid in addition to the acreage rent for solar and wind energy development grants and leases. The MW capacity fee is the approved MW capacity of the solar or wind energy grant or lease multiplied by the appropriate MW rate. A grant or lease may provide for stages of development, and the grantee or lessee will be charged a fee for each stage by multiplying the MW rate by the approved MW capacity for the stage of the project.

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Megawatt rate means the price of each MW of capacity for various solar and wind energy technologies as determined by the MW rate formula. Current MW rates are found on the BLM’s MW rate schedule, which can be obtained at any BLM office or at http://www.blm.gov. The MW rate is calculated by multiplying the total hours per year by the net capacity factor, by the MW hour (MWh) price, and by the rate of return, where: 1. Net capacity factor means the average operational time divided by the average potential operational time of a solar or wind energy development, multiplied by the current technology efficiency rates. The BLM establishes net capacity factors for different technology types but may determine another net capacity factor to be more appropriate, on a case-by-case or regional basis, to reflect changes in technology, such as a solar or wind project that employs energy storage technologies, or if a grant or lease holder or applicant is able to demonstrate that another net capacity factor is appropriate for a particular project or region. The net capacity factor for each technology type is: i. Photovoltaic (PV)—20 percent; ii. Concentrated photovoltaic (CPV) and concentrated solar power (CSP)— 25 percent; iii. CSP with storage capacity of 3 hours or more—30 percent; and iv. Wind energy—35 percent; 2. Megawatt hour (MWh) price means the 5 calendar-year average of the annual weighted average wholesale prices per MWh for the major trading hubs serving the 11 western States of the continental United States (US); and 3. Rate of return means the relationship of income (to the property owner) to revenue generated from authorized solar and wind energy development facilities based on the 10-year average of the 20-year US Treasury bond yield rounded to the nearest one-tenth percent. Screening criteria for solar and wind energy development refers to the policies and procedures that the BLM uses to prioritize how it processes solar and wind energy development right-of-way applications to facilitate the environmentally responsible development of such facilities through the consideration of resource conflicts, land use plans, and applicable statutory and regulatory requirements. Applications for projects with lesser resource conflicts are anticipated to be less costly and time-consuming for the BLM to process and will be prioritized over those with greater resource conflicts. The high-priority applications are categorized, according to 43CFR-§2804.35, that meet the criteria, as follows: 1. Lands specifically identified as appropriate for solar or wind energy development, other than designated leasing areas (DLAs); 2. Previously disturbed sites or areas adjacent to previously disturbed or developed sites;

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3. Lands currently designated as Visual Resource Management Class IV; or 4. Lands identified as suitable for disposal in BLM land use plans. The medium- and low-priority applications based on the federal land criteria are also included in this section. Sections 43CFR-§2806.50 to §2806.68 include the rents and fees requirements for solar and wind energy rights-of-way. The rule provides needed operator flexibility, bidding, and RE development in the DLAs that have “high generation with low resource conflicts.” The BLM also leases land for geothermal energy projects. As of March 2018, BLM manages 50 geothermal leases that produce approximately 5.93 BJ/hr (1,648 MW) (which amounts to more than 40% of US geothermal energy); moreover, these leases provide alternative heat sources for direct use. The production of geothermal energy on these federal lands is projected to meet the United States, target of electricity production from RE sources. The environmental impact statement (EIS) related to this geothermal leasing and via the Record of Decision, allocated approximately 449,206 km2 (111 million acres) of land, and another approximately 319,705 km2 (79 million acres) of Forest Service land is also available (BLM 2018).

RE PROGRAMS—BUREAU OF OCEAN ENERGY MANAGEMENT BOEM works under the US Department of Interior, conducts and is responsible for the RE projects on the outer continental shelf (OCS). Similar to BLM, BOEM’s RE program authorizes the leases and rights-of-way for offshore RE projects. The 30CFR—Mineral Resources, Part 585—Renewable Energy and Alternate Uses of Existing Facilities on the Outer Continental Shelf, includes the regulatory requirements on developing the RE projects in the OCS. A few selected definitions of RE terms, as included in the 30CFR, Section §585.112, are as follows (30CFR 2019): Renewable energy means energy resources other than oil and gas and minerals as defined in 30 CFR Part 580. Such resources include, but are not limited to, wind, solar, and ocean waves, tides, and current. Right-of-use and easement (RUE) grant means an easement issued by BOEM under this part that authorizes use of a designated portion of the OCS to support activities on a lease or other use authorization for renewable energy activities. The term also means the area covered by the authorization. Right-of-way (ROW) grant means an authorization issued by BOEM under this part to use a portion of the OCS for the construction and use of a cable or pipeline for the purpose of gathering, transmitting, distributing, or otherwise transporting electricity or other energy product generated or produced from renewable energy, but does not constitute a project easement under this part. The term also means the area covered by the authorization.

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Figure 2-2.  The BOEM regulatory roadmap for developing a wind energy facility. Source: BOEM (2019).

BOEM provides a schematic (Figure 2-2) of the Regulatory Roadmap (based on 30CFR, Part 585) on requirements to an offshore wind energy facility (BOEM 2019). BOEM has developed and provides the national and regional guidelines for RE projects on the OCS. The good understanding of these regulatory requirements including the timelines, application, and area-leasing guidance would lead to a better “RE Project Plan Submittal” and the approvals toward a possible 25+ year(s) of RE project. For more information on regulatory frameworks (worldwide) for RE projects in marine environment, the TETHYS (named after the Greek-Titaness of the Sea) is developed by the Pacific Northwest National Laboratory (PNNL) of the Department of Energy (DOE) with the primary functions (TETHYS 2019) “To facilitate the exchange of information and data on the environmental effects of wind and marine renewable energy technologies; and, To serve as a commons for wind and marine renewable energy practitioners and therefore enhance the connectedness of the renewable energy community as a whole.”

RENEWABLES—FEDERAL ENERGY REGULATORY COMMISSION FERC is an independent federal entity that includes licensing “hydropower projects.” FERC regulates the transmission and wholesale sales of electricity in interstate commerce; reviews the siting application for electric transmission projects under limited circumstances; licenses and inspects private, municipal, and state hydroelectric projects; monitors and investigates energy markets; enforces FERC regulatory requirements through imposition of civil penalties and other means; oversees environmental matters related to natural gas and hydroelectricity

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projects and other matters; and administers accounting and financial reporting regulations and conduct of regulated companies. However, FERC (works-with or) observes the State Public Utility Commissions, which would be responsible on areas (as applicable) outside of FERC. The use of renewable energy resources to generate electricity has the potential to be a cost-effective means not only to reduce greenhouse gas emissions, but also to diversify the fuels used to generate electricity. The Commission will continue to pursue market reforms to allow all resources, including renewable energy resources, to compete in jurisdictional markets on a level playing field. These efforts could include amendments to market rules, the modification or creation of ancillary services and related policies, or the implementation of operational tools that support the reliable integration of renewable resources. By implementing these or other reforms, the Commission’s actions have the potential to increase the amount of electricity being produced from renewable energy resources. (FERC 2019). The other useful entities and/or databases would be the DOE’s Office of Energy Efficiency and Renewable Energy—https://www.energy.gov/eere/office-energyefficiency-renewable-energy (July 22, 2019) and the Database of State Incentives for Renewables & Efficiency (DSIRE)—https://www.dsireusa.org/ (July 22, 2019).

SUMMARY The US renewable energy generation technology mix has been expansive, and the total RE consumption surpassed approximately 9.5 quintillion J (9.0 quadrillion Btu). The 42USC, Chapters 125, 134, and 149 address the RE legislative actions and associated policies, and the implemented RE technologies and programs. The active participation of various states on RE programs has been significant via the rigorous implementation of RES or RPS (Table 2-1). The BLM implemented the Solar and Wind Energy Rule via an amendment of FLPMA, to facilitate the Rights-of-Way under the Public Lands, and those applicable requirements are available in the 43CFR, Part 2800. Similarly, BOEM established the Rights-of-Way for offshore RE programs (according to applicable OCS area); the 30CFR, Part 585, provides or includes the requirements of RE programs on OCS. The FERC also has a significant role in integrating the RE resources for generation of electricity and reduction of GHGs. Thus, the effective implementation of legislative actions and regulatory approach is required to best see the success of RE programs.

DISCLAIMER The material included in this chapter is as available from those references as selected and the author’s interpretation only. For all regulatory and permitting

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verifications and confirmations on the information presented in this chapter, the federal, state, and/or local regulators shall be contacted (as needed and appropriate).

References BLM (Bureau of Land Management). 2018. “Geothermal energy.” Accessed July 20, 2019. https://www.blm.gov/programs/energy-and-minerals/renewable-energy/ geothermal-energy. BOEM (Bureau of Ocean Energy Management). 2019. “BOEM’s regulatory framework and guidelines.” Accessed July 21, 2019. https://www.boem.gov/Regulatory-Framework. 30CFR. 2019. “30CFR, Part 585—Renewable energy and alternate uses of existing facilities on the outer continental shelf.” Accessed July 20, 2019. https://www.ecfr.gov/cgi-bin/ text-idx?SID=e2b4f27d2273002068c5fcaa1409b2c7&mc=true&node=pt30.2.585&rgn =div5#se30.2.585_1100. 43CFR. 2019. “43CFR, Part 2800—Rights-of-way under the Federal Land Policy and Management Act.” Accessed July 20, 2019. https://www.ecfr.gov/cgi-bin/text-idx?SI D=b5d0331dddb9fe6b2e07c47edfd1c8a8&mc=true&node=pt43.2.2800&rgn=div5 #se43.2.2801_15. CT-PURA. 2019. “The State of Connecticut—Renewable Portfolio Standard.” Accessed July 21, 2019. https://www.ct.gov/pura/cwp/view.asp?a=3354&q=415186. DOI/BLM (US Department of the Interior, Bureau of Land Management). 2016. The Federal Land Policy and Management Act of 1976, as amended. Office of Public Affairs. Washington, DC: DOI/BLM. FERC (Federal Energy Regulatory Commission). 2019. “Integration of Renewables.” Accessed July 22, 2019. https://ferc.gov/industries/electric/indus-act/integration-renew. asp. Green, L., and C. Crume. 2017. Renewables Portfolio standard eligibility guidebook. 9th ed. Publication No. CEC-300-2016-006-ED9-CMFREV. Sacramento, CA: California Energy Commission. IEA (International Energy Agency). 2019. “Renewables.” Accessed July 21, 2019. https:// www.iea.org/topics/renewables/. NCSL (National Conference of State Legislatures). 2019. Accessed June 5, 2019. http:// www.ncsl.org/research/energy/renewable-portfolio-standards.aspx. NREL (National Renewable Energy Laboratory). 2016. U.S. laws and regulations for renewable energy grid interconnections. Rep. No. NREL/TP-6A20-66724. Golden, CO: NREL. 42USC. 2019a. “Title 42 US Code—The Public Health and Welfare, Chapter 125— Renewable Energy and Energy Efficiency Technology Competitiveness.” Accessed July 21, 2019. https://uscode.house.gov/browse/prelim@title42/chapter125&edition=prelim. 42USC. 2019b. “Title 42 US Code—The Public Health and Welfare, Chapter 134—Energy Policy, Subchapter V—Renewable Energy; and Chapter 149—National Energy Policy and Programs, Subchapter II—Renewable Energy.” Accessed July 21, 2019. https://uscode.house. gov/browse/prelim@title42/chapter134/subchapter5&edition=prelim; https://uscode. house.gov/browse/prelim@title42/chapter149/subchapter2/partA&edition=prelim. TETHYS. 2019. “Environmental Effects of Wind and Marine Renewable Energy.” Accessed September 11, 2021. https://tethys.pnnl.gov/ https://tethys.pnnl.gov/ regulatory-frameworks-marine-renewable-energy

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US-Congress. 2005. “ENERGY POLICY ACT OF 2005; PUBLIC LAW 109–58—AUG. 8, 2005.” Accessed September 11, 2021. https://www.congress.gov/109/plaws/publ58/ PLAW-109publ58.pdf USEIA (US Energy Information Agency). 2019. “US Renewable Energy Production and Consumption by Source.” Accessed July 21, 2019. https://www.eia.gov/totalenergy/data/ browser/?tbl=T10.01#/?f=M&start=200001. VA-RE. 2019. “The State of Virginia—RE model ordinances.” Accessed July 21, 2019. https://www.deq.virginia.gov/Programs/RenewableEnergy/ModelOrdinances.aspx.

CHAPTER 3

Biofuels: Ethanol and Biodiesel William F. Ritter

ETHANOL Introduction Ethanol was first used in 1826 to power an engine. In 1876, Nicolaus Otto, the inventor of the modern four-cycle internal combustion engine, used ethanol to power an early engine. In 1908, Henry Ford used ethanol to power his Model T. The first use of ethanol blended with gasoline as an octane booster was developed in the 1920s and 1930s and was in high demand during World War II because of fuel shortage (Gustafson 2019). Modern-day ethanol industry began in the 1970s when petroleum-based fuel became expensive and environmental concerns involving leaded gasoline created a need for an octane fuel. Corn became the predominant feedstock for ethanol production because of its abundance and ease of transformation into alcohol. Federal and state subsidies for ethanol helped keep the fuel in production when ethanol prices fell with crude oil and gasoline prices in the early 1980s. Ethanol’s use as an oxygenate to control carbon monoxide emissions encouraged increased production of the fuel through the decade and in the 1990s. With the phasing out of methyl tertiary butyl ether (MTBE) as an oxygenate and a desire to decrease dependence on imported oil and increase the use of environmentally friendly fuels, ethanol’s demand increased dramatically. In 2005, the first renewable fuel standard (RFS) became law as part of the United States’ energy policy (DOE 2019). The law allowed for ethanol production of 15.1 billion L/year (4 billion gal./year) in 2006 and was later amended to increase production to 28.4 billion L/year (7.5 billion gal./year) by 2012 (DOE 2019). Figure 3-1 shows global ethanol production by country or region from 2007 to 2017. Global production peaked in 2017 after a dip in 2011 and 2012. The United States is the

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Figure 3-1.  Global ethanol production 2007–2017. Source: DOE (2019).

world’s largest producer of ethanol, having produced over 60 billion L/year (16 billion gal./year) in 2017 alone. Together, the United States and Brazil produce 85% of the world’s ethanol. The vast majority of US ethanol is produced from corn, whereas Brazil primarily uses sugarcane (DOE 2019).

Legislation The Energy Policy Act was first passed by Congress in 1992 (PL 102-486). The Energy Policy Act was revised in 2005 (PL 109-58). It addressed energy production in the United States including (1) energy efficiency, (2) renewable energy, (3) oil and gas, (4) coal, (5) tribal energy, (6) nuclear matters and security, (7) vehicles and motor fuels, (8) hydrogen, (9) electricity, (10) energy tax incentives, (11) hydropower and geothermal energy, and (12) chemical charge technology. One of the provisions of the 2005 Act was to increase the amount of biofuel that must be mixed with gasoline sold in the United States (DOE 2019). The Energy Independence and Security Act (EISA) (PL 110-140) was passed and signed by President George Bush on December 19, 2007 (EPA 2019). The goal of the act was to help the United States achieve greater energy independence and security and increase the production of clean renewable fuels. The three key provisions of the act were the corporate average fuel economy standard (CAFES), the RFS, and the appliance/lighting sufficiency standard. The RFS was originally under the Energy Policy Act of 2005 which amended the Clean Air Act (CAA). The EISA of 2007 further amended the CAA by expanding the RFS program. The RFS is implemented by EPA in consultation with the US Department of Agriculture and Department of Energy. The RFS program requires a certain volume of renewable fuel to replace or reduce gasoline volume. The categories under the RFS are • Biomass-based diesel • Cellulose biofuel,

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Table 3-1.  Volume renewable standards set by EISA. Year

Cellulose fuel

2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

NA  0.1  0.25  0.5  1.0  1.75  3.0  4.25  5.5  7.0  8.5 10.5 13.5 16.0

Biomass-based diesel (billion gal.)

Advanced biofuel

Total biofuel

0.5 0.65 0.8 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0

0.6 0.95 1.35 2.0 2.75 3.75 5.5 7.25 9.0 11.0 13.0 15.0 13.0 21.0

11.1 12.95 13.95 15.2 16.55 18.15 20.5 22.25 24.0 26.0 28.0 30.0 33.0 36.0

Source: EPA (2019).

• Advance biofuel, and • Total renewable fuels. The 2007 EISA has set long-term goal of boosting the renewable fuel production to 136 billion L (36 billion gal.). It extended the yearly volume requirements out to 2022. The yearly renewable fuel requirements under the EISA are listed in Table 3-1 (EPA 2019).

Classes of Ethanol The three general categories of ethanol–gasoline blends are E10, E15, and E85. E10 is gasoline with 10% ethanol content. E15 is gasoline with 15% ethanol content, and E85 is a fuel that may contain up to 85% ethanol. In the United States, the ethanol content of most of the motor gasoline sold is 10% by volume. In June 2012, EPA approved E15 for use in flex-fuel vehicles and light-duty trucks, SUVs, and cars manufactured since 2001. The next month, a Kansas gas station became the nation’s first to offer E15. Despite EPA’s certification, E15 was denigrated by many automakers, warning that it could damage engines. Also, distributing the fuel often required station modifications, that could cost thousands of dollars. In most US markets, Reid vapor pressure (RVP) volatility restrictions currently prevent the sale of E15 to flex-fuel vehicles from June 1 to September 15, meaning most vehicles cannot purchase the ethanol blend during the busiest driving period of the year. Ethanol advocates want this restriction lifted and see it as the key to E15’s growth. There are over 1,800 stations in 31 states selling E15 blend ethanol (Growth Energy 2019). Most of them are in the Midwest where most ethanol production capacity is located. There has been an ongoing discussion with

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EPA about getting the restriction lifted. After over a decade of hard work and coordination by renewable fuel organizations such as Growth Energy, leading fuel retailers, congressional champions, rural advocates, and other key industry stakeholders, on May 31, 2019, EPA took action to remove the regulation and allow access to E15 year-round. Growth Energy predictions suggest that it will increase employment in the ethanol industry by 136,000 jobs and create a market for 26.5 billion L (7.0 billion gal.) more ethanol and 810,000 ha (2.0 million acre) of corn (Growth Energy 2019). The energy content of ethanol is about 33% less than pure gasoline. The impact of fuel ethanol on vehicle fuel economy varies depending on the amount of methanol denaturant that is added to ethanol. The energy content of the methanol denaturant is almost equal to the energy content of pure gasoline. In general, vehicle fuel economy may decrease by about 3% when using E10 relative to gasoline that does not contain fuel ethanol.

Processing of Corn Ethanol The process of making ethanol from corn is a multistep process. The first step is milling the corn. Either dry milling or wet milling is used. Figures 3-2 and 3-3 outline the process steps for wet milling and dry milling, respectively. Today most of the ethanol plants in the United States use dry milling. In wet milling, the corn kernels are broken down into starch, fiber, corn germ, and protein by heating in sulfurous acid solution for 2 days. The starch is separated and can produce ethanol, corn syrup, or food-grade starch. Additional products that are produced include corn oil, gluten meal, and gluten feed (Dutton 2019). Dry milling is a simpler process. The main products are ethanol, CO2, and dried distillers’ grain. The five steps of dry milling are (1) grinding, (2) cooking

Figure 3-2.  Wet milling process for corn ethanol. Source: RFA (2019).

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Figure 3-3.  Dry milling process for corn ethanol. Source: RFA (2019).

and liquefication, (3) saccharification, (4) fermentation, and (5) distillation. A hammer mill or roller is used for grinding. After the corn is broken down, it is mixed with heated water to form a mash or slurry. The slurry then goes through cooking and liquefication. Water interacts with the starch granules when the temperature is more than 60°C. The liquefication step is partial hydrolysis that breaks down the longer starch chains into smaller chains. The next step is saccharification, which is further hydrolyzed to glucose. The final step to make ethanol from starch is fermentation in which yeast is added. In the fermentation process, one mole of glucose yields two moles of ethanol and two moles of carbon dioxide (Dutton 2019). The final phase in ethanol production is distillation. After fermentation, the concentration of ethanol is 12% to 15% in water. Distillation is used to increase the ethanol concentration to 95%. The remaining 5% water is removed from the ethanol by dehydration. A molecular sieve containing zeolite is used to remove the water.

Cellulosic Ethanol Processing Cellulosic ethanol is made from biomass. Processing could be anything from corn stover, recycled newspaper to trees. Farmers can grow energy crops for cellulosic ethanol, including switch grass and certain trees.

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Figure 3-4.  Cellulose ethanol flow diagram. Source: DOE (2019).

Cellulosic ethanol can be made either biochemically or thermochemically (Dutton 2019). The process for biochemical ethanol is shown in Figure 3-4. In biochemical production, the biomass is first ground into bits. The bits are treated in hot sulfuric acid where the cellular walls and content dissolve. The acid pushes lignin out of the way to form hemicelluloses. The hemicelluloses then decompose into the four sugars, namely, xylose, mannose, arabinose, and galactose. The second step is called cellulose hydrolysis. The acid is washed off and the mixture goes to a tank with enzymes called cellulases, which turns cellulose into glucose. The third step is fermentation where the glucose and four hemicellulose sugars are converted to ethanol. The sugar concentration and the microbes used depend on the plant species used in the beginning. The final step is separation. Everything that is not alcohol settles to the bottom of the tank is sent for processing and reuse. The alcohol remains on the top and is sent to distillation to separate fuel-grade ethanol.

US Ethanol Production The United States has approximately 200 ethanol plants with a total capacity of 59.7 billion L/year (15.8 billion gal./year) (Figures 3-5 and 3-6). Nearly, all of the plants are located in the Midwest, with Iowa having the largest capacity at 15.9 billion L/ year (4.2 billion gal./year) followed by Nebraska with a capacity of 8.7 billion L/ year (2.3 billion gal./year) and Illinois with a capacity of 7.2 billion L (1.9 billion gal./year) (DOE 2019). Today, the United States produces more ethanol than it consumes. With the decrease in fuel consumption, the E10 blend wall has been reached, which limits the amount of ethanol consumed. When Congress revised and dramatically expanded the size and scope of the RFS in December 2007, it established annual mandates to increase biofuel consumption from less than 18.9 billion L/year (5 billion gal./year) in 2007 to 136 billion L/year (36 billion gal./year)

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Figure 3-5.  US ethanol plants and capacity 1999–2017. Source: DOE (2019).

Figure 3-6.  US ethanol production and consumption 2000–2018. Source: DOE (2019).

in 2022. Had everything gone according to the schedule set by Congress, by 2022, according to the mandate, 79.4 billion L/year (21 billion gal./year) would be filled by so-called advanced biofuels. The remaining 56.7 billion L/year (15 billion gal./ year) was implicitly reserved for corn ethanol. There has been very little about the RFS that has gone according to plan. Congress assumed that motor vehicle fuel would continue to keep rising. The bulk of biofuel today was to have been supplied by cellulosic ethanol, which was to account for the bulk of the advanced fuel mandate. There was no commercial cellulosic ethanol production when the mandates were established, but proponents of the technology were certain that commercialization would come in response to the mandates. The cellulosic ethanol mandate went into effect in 2010, when 378 million L/year (100 million gal./year) of cellulosic ethanol was required to be blended into the fuel supply (EPA 2019).

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The mandate quickly ramped up to 1.89 billion L/year (0.5 billion gal./year) in 2012, 3.78 billion L/year (1.0 billion gal./year) in 2013, and in 2017 was supposed to reach 20.8 billion L/year (5.5 billion gal./year). In reality, no commercial cellulosic ethanol was produced in 2010 or 2011, but in 2012, the first qualifying batch of cellulosic ethanol was produced. Blue Sugars Corporation produced some 75,860 L (20,069 gal.) of cellulosic biofuel in April 2012. Following this, no further cellulosic ethanol was produced in 2012 or 2013, and Blue Sugars declared bankruptcy a year later. In 2014, several new plants came online. For the most part, these plants were heavily subsidized by taxpayers, and every gallon of qualifying production also received subsidies in the form of renewable energy credits. Companies that built plants to produce cellulosic ethanol included DuPont, Abengoa, INEOS Bio, and the privately owned POET. Most of these plants have also now gone out of business, but they did manage to contribute to the production of 2,753,764 L (728,509 gal.) of cellulosic ethanol in 2014 (Rapier 2018). The CAA requires EPA to set annual RFS volumes of biofuels that must be used for transportation for the total, cellulose and biomass, advanced, and biodiesel biofuel categories. Since 2010, EPA has been adjusting the volumes below statutory targets because of market realities. For 2019, the volumes EPA set for the cellulose, biodiesel, advanced, and total biofuel categories are 1.59, 7.94, 18.59, and 75.29 billion L (0.42, 2.10, 4.92, and 19.92 billion gal.), respectively. For 2020, the volumes for cellulose, biodiesel, advanced, and total biofuel categories are 2.04, 9.19, 19.05, and 75.75 billion L (0.54, 2.43, 5.04, and 20.04 billion gal.), respectively (EPA 2020).

Greenhouse Gases In 2010, EPA released a lifecycle analysis of the greenhouse gas (GHG) emissions for corn ethanol (EPA 2010). They concluded that by 2022, corn ethanol GHG emissions from a new refinery would be 21% lower than that of an energy equivalent of gasoline. Over the years, this 21% value has dominated policy discussion and Federal regulations related to corn ethanol. The GHG profile of corn ethanol has been controversial. Searchinger et al. (2008) concluded that GHG emissions associated with its production and combustion exceeded the emissions associated with producing and combusting an equivalent quantity of gasoline. They concluded that farmers brought new land into production for corn and reduced the production of other crops on existing land to meet the corn ethanol demand. The land-use changes (LUC) resulted in corn ethanol having a higher GHG profile than gasoline. RFS under the 2007 Energy Independence and Security Act of 2007 mandated EPA to do a full GHG lifecycle analysis of corn ethanol and to include both direct and significant indirect sources of emissions. The EPA indirect sources included LUC. The Congressional Budget Office (CBO 2014) summarizes several studies on the issue of GHG emissions from corn ethanol. One of the studies by the National Research Council challenged the EPA figure of about 20% reduction in GHG emissions from corn ethanol over gasoline saying that there are several scenarios in which GHG emissions from corn ethanol are much higher than those from

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petroleum-based fuels. The CBO concluded that switching to corn ethanol over gasoline offered only limited potential to reduce overall GHG emissions. In a recent study using updated data, Flugge et al. (2017) concluded that the current GHG emissions profile for corn ethanol was 39% to 43% lower than that for gasoline. Unlike other studies on GHG benefits, which relied on forecasts of future ethanol production systems and expected impacts on the farm sector, this study reviewed how the industry and farm sectors performed in the last decade to assess the current GHG profile of corn-based ethanol. This report found greater lifecycle GHG benefits from corn ethanol than a number of previous studies, driven by a variety of improvements in ethanol production, from the cornfield to the ethanol refinery. Farmers are producing corn more efficiently and using conservation practices that reduce GHG emissions, including reduced tillage, cover crops and improved nitrogen management. Corn yields are also improving. Between 2005 and 2015, US corn yields increased by more than 10%. Between 2005 and 2015, ethanol production in the United States also increased significantly from 14.7 billion L/year (3.9 billion gal./year) to 55.9 billion L/year (14.8 billion gal./year). At the same time, advances in ethanol production technologies, such as using combined heat and power, using landfill gas for energy, and co-producing biodiesel, helped reduce GHG emissions at ethanol refinery plants. They also projected two scenarios for corn ethanol in 2022 in which the GHG emissions are 47% to 70% lower than those for gasoline (Figure 3-7). Figure 3-7 compares the full lifecycle analysis of corn ethanol GHG emissions for the 2014 current conditions, 2022 business as usual (BAU) for corn ethanol production,

Figure 3-7.  Full lifecycle corn ethanol GHG emissions for 2014 current conditions, 20022 BAU and 2022 BBS. Source: Flugge et al. (2017).

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and 2022 building block scenarios (BBS). The 70% reduction scenario assumes that refineries contract with farmers to grow corn with low-emission practices such as reduced tillage, winter cover crops, targeting nitrogen (N) fertilizer application rates, and using N inhibitors to slow down nitrification rates. Several reasons are there to find greater lifecycle GHG benefits from corn ethanol than some previous studies. Previous estimates anticipated that growing corn to produce ethanol would result in “indirect land-use change.” In other words, the land would be converted from grasslands and forests to commodity production as a result of increased demand for corn used in ethanol production. However, based on new data and research, there is compelling evidence that, although LUC have occurred, the actual patterns of changes and innovation within the farm sector have resulted in these indirect emissions being much lower than previously projected.

Water Quality Impacts The Mississippi River Basin (MRB) encompasses more than 55% of the US agricultural land (Goolsby and Battaglin 2000) and more than 75% of the corn, cotton, rice, sorghum, wheat, and forage area. In 2015, the total value of all crop production in the conterminous United States was about $184 billion, with field crops accounting for $143.4 billion, commercial vegetable crops $13.4 billion, and fruit and nuts $27.1 billion (USDA 2017). The value of field and miscellaneous crop production (not including commercial vegetables, fruits, or nuts) within the MRB in 2015 was estimated at $131.6 billion, which represents more than 90% of the field and miscellaneous crop production value in the United States. Row crop agriculture in the Midwest has had an impact on water quality in the Gulf of Mexico over the years. A hypoxic zone in the northern Gulf of Mexico has been forming each summer since the 1950s. Measurements of the hypoxic zone started in 1985 (MTF 2008). The Gulf’s hypoxic zone is caused by excessive nutrient pollution in MRB. The excess nutrients stimulate algae growth, which sinks and decomposes and lowers oxygen levels below a point that cannot support most marine life. Every year NOAA predicts the size of the hypoxic zone based on USGS data. The major factor contributing to the size of the hypoxic zone every summer is the USGS May nitrogen and phosphorus nutrient load data. The Mississippi River/Gulf of Mexico Watershed Nutrient Task Force (MTF) was established in the fall of 1997 to understand the causes and effects of eutrophication in the Gulf of Mexico, coordinate activities to reduce the size and duration, and ameliorate the effects of hypoxia. In 2008, the MTF released the 2008 Action Plan (MTF 2008), which called for the MTF to complete and implement comprehensive nitrogen and phosphorus reduction strategies for the states within the MRB. Each state was to develop strategies for reducing nitrogen and phosphorus loads by 20% and 45%, respectively. In Illinois, extensive analyses conducted by researchers at the University of Illinois estimated that point sources and agricultural nonpoint sources contributed 48% of the total phosphorus (TP) reaching the Mississippi River from that state. Agriculture was the source of 80% of the nitrate-nitrogen; point sources

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contributed about 18%. Urban runoff contributed 4% of the TP and 2% of the nitrate-nitrogen. The tile-drained areas of central and northern Illinois are the largest source of nitrate. Sloping, erosive soils in western and southern Illinois are the largest contributor of nonpoint TP (ILEPA 2014). The Iowa Department of Agriculture and Land Stewardship, the Iowa Department of Natural Resources (Iowa DNR), and Iowa State University developed a science and technology-based framework to assess and reduce nutrients to Iowa waters and the Gulf of Mexico (IOWA 2019). On an annual basis, most nutrient loads in Iowa come from nonpoint sources. It is estimated that 83% of the nitrogen load to Iowa streams comes from nonpoint sources and 7% from point sources and 79% of the phosphorus load comes from nonpoint sources and 21% from point sources. Annual row crop production, coupled with usually abundant rainfall, facilitates the vast majority of nitrogen transport to streams in Iowa with a large majority discharged as nitrates through tile drainage. The sources of phosphorus include agricultural nonpoint source runoff and streambank erosion. As part of Minnesota’s nutrient reduction strategy, the state conducted a comprehensive science assessment that incorporated nutrient conditions, trends, sources, and pathways. The nutrient source assessment was based on multiple Minnesota Pollution Control Agency (MPCA) studies and engaged numerous local, state, and federal partners. During an average precipitation year, cropland sources contribute an estimated 78% of the nitrogen load to the Mississippi River in Minnesota. Cropland nitrogen reaches surface waters through two dominant pathways: tile drainage transport; and leaching to groundwater and subsequent flow to surface waters. The primary sources of phosphorus transported to streams are cropland runoff, permitted wastewater, and streambank erosion (MPCA 2014). In the major corn-growing states such as Iowa, Illinois, and Minnesota, the major sources of nitrogen and phosphorus are from agriculture. All three of these states have extensive tile drainage which transports a large percentage of the nitrates to streams. The major sources of phosphorus and nitrogen in the MRB as predicted by the USGS SPARROW model are shown in Figures 3-8 and 3-9 (MTF 2017). The major sources of nitrogen are from fertilizers, whereas the major sources of phosphorus are from fertilizers and manure. The annual total nitrogen (TN), nitrate, and TP loads from the MRB to the Gulf of Mexico from 1980 to 2017 are shown in Figures 3-10, 3-11, and 3-12 (TP is shown up to 2015), respectively (USGS 2017). Annual TN loads have been below the average annual baseline load from 1980 to 1996 for most years from 1997 to 2017. There has been no decrease in the annual TP loads. Best management practices (BMPs) for nitrogen and phosphorus may be classified as source management or transport management (Sharpley et  al. 2001). Some of the source management BMPs that will reduce both nitrogen and phosphorus losses are • Application nutrient rates that meet crop needs; • Method of application;

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Figure 3-8.  Major sources of phosphorus in the MRB. Source: MTF (2017).

Figure 3-9.  Major sources of nitrogen in the MRB. Source: MTF (2017).

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Figure 3-10.  Annual total nitrogen loads from the MRB to the Gulf of Mexico 1980–2017. Source: USGS (2017).

• Timing of application; • Manure management such as composting, storage ponds, or lagoons; and • Adding alum as a manure additive. Some of the transport BMPs that will reduce both nitrogen and phosphorus losses are • Winter cover crops, • Conservation tillage will reduce TN and TP losses but may increase nitrate losses, • Grass or forest buffers at the edge of fields next to streams,

Figure 3-11.  Annual nitrate plus nitrite loads from the MRB to the Gulf of Mexico 1989–2017. Source: USGS (2017).

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Figure 3-12.  Annual total phosphorus loads from the MRB to the Gulf of Mexico 1980–2015. Source: USGS (2017).

• Wetland areas and grassed waterways, • Terraces, • Strip cropping, • Critical source treatment areas, and • Sediment delivery structures. Since the late 1990s, the development of methods to reduce losses of nitrogen in drainage waters has become a primary objective in addressing the environmental impacts of agricultural drainage for researchers and engineers. Reducing nitrogen losses is difficult because the nitrate form is mobile in soil solution and may be readily leached with subsurface drainage water. A number of methods may be used to reduce losses. They include source reduction by fertilizing at appropriate rates and times, cover crops, routing drainage water through wetlands, use of biofilters, saturated buffers, reduced drainage intensity, and drainage water table management, also known as controlled drainage (CD). CD can reduce nitrate loads at an average of 30% in the Midwest, although this can range from 15% to 75% (Christianson et al. 2016).

Pros and Cons of Ethanol Savin (2019) of Alternative Energies has summarized some of the pros and cons of corn ethanol. Some of the pros of ethanol are • Ethanol is a biofuel that can lower the level of GHG emissions released by the transportation sector. • Ethanol can be produced from cheap raw materials such as corn and sugarcane.

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• Ethanol is an energy-balanced fuel that is produced from corn and generates 1.06 units of energy for any 1 unit of energy used. • Production of ethanol generates useful by-products. • Ethanol generates lower GHG emissions than fossil fuels and is also biodegradable. Some of the cons of ethanol are • Ethanol is less effective than gasoline. • Crops used to produce ethanol occupy a large surface of land. • In the United States, 40% of the corn crop production goes toward ethanol production instead of being used as food. • It is an alternate fuel that is heavily subsidized

BIODIESEL Introduction The diesel engine was developed in the 1890s by inventor Rudolph Diesel. Today, the diesel engine has become the engine of choice for power, reliability, and high fuel economy worldwide. Early experiments on vegetable oil fuels were conducted by the French government and Dr. Diesel himself. Dr. Diesel envisioned that pure vegetable oils could power early diesel engines for agriculture in remote areas of the world, where petroleum was not available at the time. The early diesel engines were designed to run on many different fuels, from kerosene to coal dust. The first public demonstration of vegetable oil–based diesel fuel was at the 1900 World’s Fair, when the French government commissioned the Otto company to build a diesel engine to run on peanut oil (Pacific Biodiesel 2019). Shortly after Dr. Diesel’s death in 1913, petroleum became widely available in a variety of forms, including the class of fuel we know today as “diesel fuel.” With petroleum being available and cheap, the diesel engine design was changed to match the properties of petroleum diesel fuel. Owing to the widespread availability and low cost of petroleum diesel fuel, vegetable oil–based fuels gained little attention, except in times of high oil prices and shortages. World War II and the oil crises of the 1970s saw a brief interest in using vegetable oils to fuel diesel engines. Unfortunately, the newer diesel engine designs could not run on traditional vegetable oils, because of the much higher viscosity of vegetable oil compared with that of petroleum diesel fuel. It was a Belgian inventor in 1937, who first proposed using transesterification to convert vegetable oils into fatty acid alkyl esters and use them as a diesel fuel replacement. The transesterification reaction is the basis for the production of modern biodiesel. Pioneering work in Europe and South Africa by researchers, such as Martin Mittelbach, furthered the development of the biodiesel fuel industry in the early

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1990s, with the US industry coming on more slowly, because of lower prices for petroleum diesel. Pacific Biodiesel became one of the first biodiesel plants in the United States in 1996 to establish a biodiesel production operation to recycle used cooking oil into biodiesel on the island Maui in Hawaii. The biodiesel industry became a household name in the United States, after the terrorist attacks of 9/11/2001 resulted in historically high oil prices and increased awareness of energy security. By 2005, worldwide biodiesel production had reached 4.2 billion L/year (1.1 billion gal./year) with most fuel being produced in the European Union.

Biodiesel Processing Biodiesel can be made from nearly any feedstock that contains free fatty acids, which are the raw materials that are converted to biodiesel through a process called transesterification. Most biodiesel in the United States is produced from vegetable oils. Other feedstocks (raw materials) include waste animal fats from processing plants and recycled used cooking oil and grease from restaurants. A flow diagram of the biodiesel production process is shown in Figure 3-13. In the transesterification process,-fats and oils are converted into biodiesel and glycerol (Figure 3-14) (Van Gerpen et al. 2004). Fats and oils are reacted with a short-chain alcohol in the presence of a catalyst, producing fatty acid esters that are primely the molecules in biodiesel. Methanol is usually the alcohol used in the process, and, in general, either sodium hydroxide or potassium hydroxide is used as the catalyst. The methanol is recovered in the process and reused. Approximately 45.4 kg (100 lb) of oil or fat is reacted with 4.5 kg (10 lb) of a shortchain alcohol to form 45.4 kg (100 lb) of biodiesel and 4.5 kg (10 lb) of glycerol (EIA 2020).

Figure 3-13.  Biodiesel processing flow diagram. Source: DOE (2020).

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Figure 3-14.  Biodiesel transesterification reaction. Source: Van Gerpen et al. (2004).

The glycerol produced in biodiesel production contains numerous impurities. There are various outlets for disposal and utilization of the crude glycerol generated in biodiesel plants. Many large-scale biodiesel producers refine the glycerol into a pure form and then it can be used in the food, pharmaceutical, or cosmetics industries. For small-scale producers, however, purification is too expensive to be performed in their manufacturing sites. Their crude glycerol is usually sold to large refineries for upgradation. In recent years, however, with the rapid expansion of the biodiesel industry, the market is flooded with excessive crude glycerol; thus, producers need to seek new value-added uses for this glycerol or dispose it. Combustion is the common method for glycerol disposal (EIA 2020).

Classes of Biodiesel Blends Biodiesel can be blended and used in many different concentrations. The most common are B5 (up to 5% biodiesel) and B20 (6% to 20% biodiesel). B100 (pure biodiesel) is typically used as a blend stock to produce lower blends and is rarely used as a transportation fuel. B20 is the most common biodiesel blend. It represents a good balance of cost, emission, cold-weather performance, material compatibility, and ability to act as a solvent. Engines operating on B20 have similar fuel consumption, horsepower, and torque to engines running on petroleum diesel. Pure biodiesel contains less energy on a volumetric basis than petroleum diesel. High-level biodiesel blends can also impact engine warranties, can gel in cold temperatures, and may present unique storage issues. B100 use could also increase nitrogen oxide emissions, although it greatly reduces other toxic emissions (EIA 2020).

US Biodiesel Production Biodiesel production and exports and consumption from 2001 to 2019 are shown in Figure 3-15 (DOE 2020). The biodiesel diesel industry has grown since 2010, with commercial production facilities from coast to coast. The industry reached a

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Figure 3-15.  US biodiesel production, exports, and consumption. Source: DOE (2020).

key milestone in 2011, when it produced 3.78 billion L/year (1.0 billion gal./year) for the first time. By 2015, the market had doubled to more than 7.6 billion L/ year (2.0 billion gal./year). In 2019, the market was 6.8 billion L/year (1.8 billion gal./year). The industry’s total production continues to significantly exceed the biodiesel requirement under the Federal RFS and has been sufficient to fill a majority of the advanced biofuel requirement. The various feedstocks used in the United States to produce biodiesel in 2019 are shown in Figure 3-16. Soybean oil is by far the largest feedstock used (57%). Animal fats account for 8% of the feedstocks used. A total of (approximately) 5.79 billion kg (12.75 billion lb) of feedstock was used to produce biodiesel in 2019 (EIA 2020).

Figure 3-16.  Feedstocks used for biodiesel production in 2019. Source: EIA (2020).

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For the year 2020, under the RFS, the final volume requirements for cellulosic biofuel, biodiesel or BBD, advanced biofuel (in total), and renewable fuel (in total) categories are: 2.23, 9.20, 19.27, and 76.04 billion L [0.59, 2.43 (for the year 2021, as well), 5.09, and 20.09 billion gal.], respectively (note that all values are ethanol-equivalent on an energy content basis, except for BBD which is biodieselequivalent) (CRS 2020, EPA 2020).

SUMMARY The Energy Independence and Security Act (EISA) (PL 110-140) was passed in 2007 (EPA 2019). The goal of the act was to help the United States achieve greater energy independence and security and increase the production of clean renewable fuels. By 2022, the 2007 EISA set boosting the long-term goal to 136 billion L (36 billion gal.) of renewable fuel. Had everything gone according to the schedule set by Congress, by 2022 according to the mandate, 21 billion gal./ year would be filled by so-called advanced biofuels. The remaining 15 billion gal./year was implicitly reserved for corn ethanol. Very little about the RFS has gone according to the plan; today, no significant level of cellulosic ethanol has been produced. Biodiesel can be made from nearly any feedstock that contains free fatty acids, which are the raw materials that are converted to biodiesel through a process called transesterification. Most biodiesel in the United States is produced from vegetable oils. In 2019, the market for biodiesel in the United States was 6.8 billion L/year (1.8 billion gal./year). In 2019, the industry used a total of 5.79 billion kg (12.75 billion lb) of feedstock to produce biodiesel (EIA 2020). Soybean oil (57%) was the largest feedstock used to produce biodiesel.

References CBO (Congressional Budget Office). 2014. The renewable fuel standard issue for 2014 and beyond. Washington, DC: CBO. Christianson, L. E., J. Frankenberger, C. Hay, M. J. Helmers, and G. Sands. 2016. Ten ways to reduce nitrogen loads from drained cropland in the Midwest. Pub. C1400. UrbanaChampaign, IL: Univ. of Illinois Extension. CRS (Congressional Research Service). 2020. The Renewable Fuel Standard (RFS): An overview (updated April 14, 2020); the CRS Report #R43325. Accessed December 13, 2020. https://crsreports.congress.gov/product/pdf/R/R43325. DOE (US Department of Energy). 2020. “Biodiesel production and distribution.” Alternative Fuels Data Center, DOE. Accessed June 26, 2020. https://afdc.energy.gov/ fuels/biodiesel_production.html and https://afdc.energy.gov/laws/RFS. DOE. 2019. “Maps and data.” Alternative Fuels Data Center, DOE. Accessed July 26, 2019. https://afdc.energy.gov/data/. Dutton, J. A. 2019. Alternate fuels from biomass. EGEE 439 e-Education Institute. University Park, PA: Pennsylvania State Univ. Accessed June 5, 2019. https://www.e-education.psu. edu/egee439/node/673.

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EIA (US Energy Information Administration). 2020. “Biofuels explained biomass-based diesel facts.” Accessed June 26, 2020. https://www.eia.gov/energyexplained/biofuels/ biodiesel.php. EPA (US Environmental Protection Agency). 2010. “Renewable fuel standard program regulatory impact analysis.” EPA-420-R-10-006. Accessed June 26, 2019. https://nepis.epa.gov/EPA/html/DLwait.htm?url=/Exe/ZyPDF.cgi/P1006DXP. PDF?Dockey=P1006DXP.PDF. EPA. 2019. “Renewable fuels program statues.” Accessed June 25, 2019. https://www.epa. gov/renewable-fuel-standard-program/statutes-renewable-fuel-standard-program. EPA. 2020. “Final renewable fuel standards for 2020, and the biomass-based diesel volume for 2021.” Accessed June 11, 2020. https://www.epa.gov/renewable-fuel-standard-program/ final-renewable-fuel-standards-2020-and-biomass-based-diesel-volume. Flugge, M., J. Lewandrowski, J. Rosenfeld, C. Boland, T. Hendrickson, K. Jaglo, et  al. 2017. A life-cycle analysis of the greenhouse gas emissions of corn-based ethanol. Report prepared by ICF under USDA Contract No. AG-3142-D-16-0243. Accessed July 26, 2019. https://www.usda.gov/media/press-releases/2017/01/12/usda-releases-new-report-life​ cycle-greenhouse-gas-balance-ethanol. Goolsby, D. A., and W. A. Battaglin. 2000. Nitrogen in the Mississippi basin-estimating sources and predicting flux to the Gulf of Mexico. US Geological Survey Fact Sheet 13500. Accessed July 25, 2019. http://ks.water.usgs.gov/Kansas/pubs/fact-sheets/fs.135-00. html. Growth Energy. 2019. Expanding access to biofuels with year-round E15. Washington, DC: Growth Energy. Accessed July 6, 2019. https://growthenergy.org/policy-priorities/ yearrounde15/. Gustafson, C. 2019. History of ethanol production and policy. NDSU Extension Fact Sheet. Fargo, ND. Accessed June 5, 2019. https://www.ag.ndsu.edu/energy/biofuels/ energy-briefs/history-of-ethanol-production-and-policy. ILEPA (State of Illinois EPA). 2014. “Illinois nutrient loss reduction strategy.” Accessed July 25, 2019. http://www.epa.illinois.gov/topics/water-quality/watershed-management/ excess-nutrients/index. IOWA (State of Iowa). 2019. “Iowa nutrient reduction strategy 2017–18 annual report.” Iowa Dept. of Agriculture and Land Stewardship, Iowa Dept. of Natural Resources, and Iowa State Univ. College of Agriculture and Life Sciences. Accessed June 12, 2019. http:// www.nutrientstrategy.iastate.edu>documentsNRS2018annualreportdocs. Mississippi River/Gulf of Mexico Watershed Nutrient Task Force (MTF). 2008. “Gulf hypoxiation plan 2008 for reducing, mitigating, and controlling hypoxia in the northern Gulf of Mexico and improving water quality in the Mississippi River basin.” Washington, DC: US Environmental Protection Agency, Office of Wetlands, Oceans, and Watersheds, Mississippi River/Gulf of Mexico Watershed Nutrient Task Force. Accessed July 25, 2019. http://water.epa.gov/type/watersheds/named/msbasin/ bupload/2008_8_28_msbasin_ghap2008_update082608.pdf. Mississippi River/Gulf of Mexico Watershed Nutrient Task Force (MTF). 2017. “Mississippi River/Gulf of Mexico watershed nutrient task force 2017 report to Congress.” 2nd Biennial Report. Washington, DC: US Environmental Protection Agency, Office of Wetlands, Oceans and Watersheds, Mississippi River/Gulf of Mexico Watershed Nutrient Task Force. Accessed July 25, 2019. https://www.epa.gov/ms-htf/hypoxia-task-force-reports-congress. MPCA (Minnesota Pollution Control Agency). 2014. The Minnesota nutrient reduction strategy. St. Paul, MN: Minnesota Pollution Control Agency. Accessed July 25, 2019. http://www.pca.state.mn.us/index.php/view-document.html?gid=20213.

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Pacific Biodiesel. 2019. “The history of biodiesel fuel.” Accessed June 10, 2020. https:// www.biodiesel.com/history-of-biodiesel-fuel/. Rapier, R. 2018. “Cellulosic ethanol falling far short of the hype.” Forbes. Accessed June 26, 2019. https://www.forbes.com/sites/rrapier/2018/02/11/cellu ​losic-etha ​nol-fall​ ing-far-short-of-the-hype/#5975fee3505f. RFA (Renewable Fuels Association). 2019. How is ethanol made. Washington, DC: RFA. Accessed June 25, 2019. https://ethanolrfa.org/how-ethanol-is-made/. Savin, M. 2019. “Pros and cons of ethanol”. Alternative Energies. Accessed June 19, 2019. https://www.alternative-energies.net/what-is-ethanol-pros-and-cons/. Searchinger, T., R. Heimlich, R. A. Houghton, F. Dong, A. Elobeid, J. Fabiosa, et al. 2008. “Use of cropland for biofuels increases greenhouse gases through emissions from landuse change.” Science 319 (#5867): 1238–1240. Sharpley, A. N., R. W. McDowell, J. L. Weld, and P. J. A. Kleinman. 2001. “Assessing site vulnerability to phosphorus loss in an agricultural watershed.” J. Environ. Qual. 30: 2026–2036. USDA (US Department of Agriculture). 2017. “Crop values 2017 summary, February 2018.” USDA National Agricultural Statistics Service (USDA NASS). Accessed August 2, 2019, and December 13, 2020. http://usda.mannlib.cornell.edu/usda/current/CropValuSu/ CropValuSu-02-24-2017.pdf and https://www.nass.usda.gov/Publications/Todays_ Reports/reports/cpvl0218.pdf. USGS. 2017. “Watershed loadings for the Mississippi River and subbasins.” US Dept. of Interior, USGS. Accessed August 3, 2019, and December 13, 2020. https://nrtwq.usgs. gov/mississippi_loads/#/ and https://nrtwq.usgs.gov/nwqn/#/. Van Gerpen, J., B. Shanke, R. Pruszko, D. Clements, and G. Knothe. 2004. Biodiesel production technology August 2002 to January 2004. Rep. No. NREL/SR-510-362-44. Golden, CO: National Research Energy Laboratory. Accessed December 13, 2020, and June 8, 2020. https://www.nrel.gov/docs/fy04osti/36244.pdf and https://www.nrel. gov>doc>R-510-36244.pdf.

CHAPTER 4

Micro-Hydropower: Concept, System Design, and Innovations Tamim Younos, Juneseok Lee

INTRODUCTION Hydropower can simply be defined as “flowing water’s energy” that performs a useful task. Ancient civilizations used hydropower in the form of waterwheel to grind wheat into flour (Nunez 2019). A well-known hydropower device, which dates back to the eighteenth century, is the hydraulic ram—a cyclic water pump that takes advantage of the water hammer effect (Rayner 1995). The pump uses a unidirectional valve to create a perpetual cycle of water flow in which a small portion of the inflow water is pumped via a delivery pipe, whereas excess water is expelled through a waste valve (Figure 4-1). Hydro rams are still popular for providing water for multiple uses in small communities and remote areas and other uses, such as operating a water fountain. The theme of this chapter is using “flowing water’s energy” to generate electricity. The history of hydropower development for electricity generation in the United States dates back to the late nineteenth century (Nunez 2019, EERE 2019a). In 1881, using direct current (DC) technology, a dynamo connected to a turbine in a flour mill provided street lighting at Niagara Falls, New York, and in 1893, the first commercial installation of an alternating current (AC) hydropower plant at the Redlands Power Plant in California allowed power to be transmitted longer distances for consumer use (EERE 2019a). At present, hydropower is the most widely used renewable energy source and represents about 17% of the total electricity production in the world (IEA 2018). China is the largest producer of hydroelectricity, followed by Canada, Brazil, and the United States. Hydropower accounts for nearly 9% of the US electric generating capacity (USGS 2018).

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Figure 4-1.  Basic components of a hydraulic ram: (1) inlet (drive pipe), (2) free flow at waste valve, (3) outlet (delivery pipe), (4) waste valve, (5) delivery check valve, and (6) pressure vessel. Source: Wikipedia https://en.wikipedia.org/wiki/Hydraulic_ram (available at public domain).

Table 4-1.  Hydropower Plant Size and Capacity. Plant size Large hydropower Small hydropower Micro-hydropower

Power-generation capacity >30 MW 100 kW–30 MW Up to 100 kW

Source: EERE (2019b).

The most common and traditional type of a hydropower plant uses a dam on a river that stores water in a reservoir. The water is released from the reservoir— creating total hydraulic/energy head (i.e., a sum of pressure, elevation, and velocity head)—and supplied to a turbine—a rotary engine that converts moving water to mechanical energy—which, in turn, activates a generator—a device that converts mechanical energy to electrical energy. However, a dam is not necessarily required to generate power. Electricity can be generated from any stream flow or pipe flow with enough hydraulic head that can turn a (suitable) turbine. A system can be put in place with as little as 0.61 m (2 ft) of head with high flow or as little as 0.008 m3/min (2 gal./min) of flow with high head (Alternative Energy News 2018). Table 4-1 shows a hydropower plant size based on its power generation capacity, which, in turn, depends on the available water flow rate and hydraulic head (EERE 2019b). The focus of this chapter is on micro-hydropower generation (up to 100 kW).

MICRO-HYDROPOWER GENERATION: CONCEPT A micro-hydropower plant is basically a small-scale decentralized energy generation infrastructure. In terms of electricity use, a micro-hydropower plant can be configured in two ways: (1) integrated into the conventional electric grid and (2) a stand-alone electricity source, when an electric grid is not available. Micro-hydropower is particularly useful for meeting electricity demand in rural environments, small farms, and remote communities. Micro-hydropower can also have specific urban applications, such as generating power for street lighting and other uses.

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Figure 4-2.  Typical schematic of a small-scale hydropower generation system. Source: DOE (2010).

A micro-hydropower generation plant location is site specific and depends on the topographic characteristics of the site. For example, a section of the river/ stream that contains a natural waterfall can be a suitable site. A common practice is to construct a diversion channel from the mainstream to create the hydraulic head, that is, a vertical distance from the water source to a turbine. Figure 4-2 shows major elements of the water conveyance system for a microhydropower plant. These include a water intake weir, settling basin, constructed channel, forebay tank or reservoir, and penstock. The penstock is a pipe that transports water from the channel to a turbine located in the power house at the base of a site. Figure 4-3 shows the technical concept of a micro-hydropower system based on field conditions. Two major field design factors are the available hydraulic head (H) and the flow rate (Q). Equation (4-1) can be used to estimate the potential available power (P)

P = η ρ g H Q

where η = Turbine efficiency, ρ = Density of water (kg/m3), g = Acceleration of gravity (m/s2), H = Hydraulic head (m), and Q = Flow rate (volume over time).

(4-1)

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Figure 4-3.  The basic concept of a micro-hydropower generation system. Source: DOE (2010).

MICRO-HYDROPOWER SYSTEM DESIGN In this section, the system design for a micro-hydropower plant is illustrated by a case study project. The goal of the case study project illustrated herein was to design and install a modern micro-hydropower plant for educational purposes.

Case Study Site The case study site is located in Glen Alton, a historic site located within the Jefferson National Forest in Giles County, Virginia, where a micro-hydropower plant was built in the 1940s (Younos 2013). The site, originally private property, was donated to the Federal government and is maintained by the US Forest Service as a sustainability education demonstration site. In the 1940s, the property owner, Lucas, constructed a dam [Figure 4-4(a)] on the North Fork Creek, a stream that ran through his property, and also a 271.3 m (890 ft) channel that diverted water from the North Fork Creek [Figure 4-4(b)].

Figure 4-4.  (a)The dam, (b) the channel, and (c) original powerhouse. Source: Student team.

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The channel supplied water to a turbine that generated electricity for use on his property [Figure 4-4(c)]. The original power plant at Glen Alton was abandoned when the property was connected to the electric grid.

Micro-Hydropower System Design Components Figure 4-5 shows an overview of the case study site at Glen Alton. Red segments in Figure 4-5 depict components of the new system design described in this section (Table 4-2). Black segments depict project components, such as the dam and the overflow creek that already existed. The electrical component in the powerhouse does not show the battery bank that was added later in the updated design. The Glen Alton system is capable of producing 6 to 8 A (power outputs up to 2 kW) when operating at the design H and Q. The 2 kW rating falls within the lower range of a micro-hydropower generation capacity. However, the design principles described herein apply to all power ranges. The generated electricity is used to power lights and a stand-alone heating/cooling unit at the Glen Alton lodge. Details of system design components are described subsequently.

Hydraulic Component Design Hydraulic component design parameters include hydraulic head and flow rate at the site, penstock design, and intake water filtration (Table 4-2).

Figure 4-5.  Overview of the case study project at Glen Alton. Source: Student team.

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Table 4-2.  System Design Components for a Modern Micro-Hydropower Plant. Hydraulic component

Mechanical component

Electrical component

Field conditions: hydraulic head (H) and flow rate (Q) Penstock design Penstock intake filter

Turbine

Electrical generator (alternator)

Turbine flow control Turbine–generator interface —

Inverter Controller

Penstock flow control

Battery bank

Source: Younos (2013).

Hydraulic Head Standard surveying procedures were applied to determine the design hydraulic head (H), that is, a change in the elevation (vertical distance) between the water source channel (forebay tank) and the turbine to be located in the power house. Figure 4-6 shows the constructed channel (2% slope) and the measured hydraulic head (H) 6.4 m (20.93 ft) at the case study site.

Flow Rate A temporary dam is constructed to measure the volumetric flow rate of a small stream. At the case study site, water discharge at the temporary dam near the penstock intake was collected to fill a container of known volume [0.0038 m3 (5 gal.)] and the filling time was recorded. Using this method, time to fill known volume (i.e., flow rate = volume/time to fill), the estimated design flow rate (Q) was calculated at 0.95 m3/min (250 gpm).

Flow Control to Penstock It is critical that water supply to penstock meet the design flow criteria and remain at a constant flow. A 1.22 m (48 in.) deep weir, which spans 3.66 m (12 ft) across

Figure 4-6.  Hydraulic head at the Glen Alton micro-hydropower project site (1 ft = 0.3048 m). Source: Younos (2013).

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Figure 4-7.  Flow control weir at the case study site. Source: Student team.

the channel, is constructed immediately upstream from the penstock intake (Figure 4-7). Weir outflow is connected via an underground pipe to the penstock intake, where the filtration unit is installed (discussed later). Preliminary investigation detected that segments of the old channel were leaking. Dolomite was used to fill the leaking segments of the channel.

Penstock Design Other than hydraulic head and flow control, critical penstock design parameters include the following: (1) pipe material, which determines the pipe durability and cost; and (2) penstock pipe length and diameter, which determines the head loss and flow capacity to the turbine. Pipe Material Three decision factors to determine penstock material are durability, pressure rating, and cost. Polyvinyl chloride (PVC) pipes and high-density polyethylene (HDPE) pipes are considered suitable pipe materials for the penstock. HDPE pipe is typically less expensive than PVC, but its pressure rating is lower than PVC. As shown in Table 4-3, based on a professional engineering judgment, a weight was assigned to each decision factor to create a selection matrix (durability 35%, pressure rating 35%, and cost 30%). It was determined that except for the cost, the normalized score for PVC was higher than that for HDPE. Thus, PVC was selected as the penstock pipe material. The required pipe length was 9.9 m (32.6 ft) (Figure 4-5).

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Table 4-3.  Selection Matrix for the Penstock Pipe Material. PVC Decision factor Durability Pressure rating Cost Total

HDPE

Weight (%)

Normalized score

Weighted score

Normalized score

Weighted score

35 35 30

0.78 0.73 0.60

27.22 25.67 18.00 70.89

0.56 0.33 0.73

19.44 11.67 22.00 53.11

Source: Younos (2013).

Pipe Diameter As a general rule, a larger pipe diameter yields a lower flow velocity and lower head loss. Although the larger penstock pipe diameter reduces head loss, it may result in a higher cost, and, therefore, it is a critical decision factor. Based on friction loss for schedule 40 PVC pipe [class of 160 psi (4,206 kPa) PVC pipe], it was determined that an 8 in. (20.3 cm) diameter (inner) PVC pipe was the optimal diameter pipe for the penstock. For the 8 in. (20.3 cm) pipe diameter and 0.95 m3/ min (250 gpm) flow rate, the estimated head loss was 0.12 ft per 100 ft of the pipe length (0.12 m per 100 m).

Penstock Intake Filter The turbine and generator should be protected from objects, such as fish, leaves, twigs, and rocks. A filter is needed at the penstock water intake to remove these objects. After a very thorough investigation and evaluation of various filtration methods, a Coanda effect hydro-shear screen was purchased from Hydroscreen LLC, Denver, Colorado (Figure 4-8), for the case study site. This type of screen is relatively new to small-hydropower projects but has had great success in largescale applications. The filter efficiently removes objects from flowing water using a “wedge-wire” design where water flow is accelerated over a wedge-wire screen, which shears the flow and forces the debris down the inclined screen (Figure 4-8). The filtration unit is self-cleaning and requires minimal maintenance.

Mechanical Component Design As shown, in Table 4-2, mechanical components include the turbine, flow control devices, and turbine–generator interface (connector). A water turbine is a rotary engine that converts moving water to rotational mechanical energy—the water pushes a series of blades mounted on a shaft. The shaft is electromagnetically coupled to an electric generator (alternator). The turbine selection depends on hydraulic head (H) and design flow (Q) at the site. After preliminary investigation, the following turbine types available in the market were found as potential choices: the Wild Nature Solutions LV1500 turbine (Missouri Wind and Solar, Seymour, Missouri), the energy systems and

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Figure 4-8.  Schematic showing operation of a typical Coanda effect screen unit. Source: US Bureau of Reclamation (2003).

design’s stream-engine turbine, and a custom-built cross-flow turbine. The option of custom-building a cross-flow turbine involves a significant effort of planning and construction and, therefore, was not considered. For micro-hydropower plants, impulse turbines (e.g., Pelton wheel and the Turgo wheel) are the preferred turbine type (impulse turbines rely on the velocity of water to turn the turbine wheel (called the runner). The Turgo impulse wheel, an upgraded version of the Pelton wheel, can move twice as fast (higher efficiency) and is known to require less maintenance. The Wild Nature Solutions LV1500 turbine requires more maintenance and costs higher than Energy Systems and Design’s (Sussex, New Brunswick, Canada) Stream Engine turbine. Therefore, an LV1500 four (4) nozzle high-precision bronze Turgo wheel turbine (StreamEngine turbine) (Energy Systems and Design) was selected for the case study site (Figure 4-9). Other components needed to be compatible with the selected turbine (Stream Engine Manual 2017). Turbine Flow Control The water supply nozzle diameter through which water is supplied from the penstock to the turbine is an important design factor. Appropriate nozzle diameter selection is based on the head and flow rate and the turbine type. For the case study site conditions using the Turgo turbine, four nozzles of 0.022 m (0.875 in.) diameter (at 925 rpm) are used. The tube connecting the penstock outlet to the turbine intake is also a critical factor as it impacts head loss and power output. Flexible braided vinyl tubing (smooth and minimized sharp bends) was selected to connect the penstock pipe outlet to the nozzle inserts of the turbine. A gate valve that controls the amount of water supplied to the turbine is installed in each of the four water lines that connect the penstock to the turbine [Figures 4-9(b) and 4-10].

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Figure 4-9.  (a) Top view of a turbine-generator system, and (b) LV1500 four-nozzle turbine. Source: Energy Systems & Design, n.d.; reproduced with permission.

Figure 4-10.  Turbine flow control. Source: Energy Systems & Design, n.d.; reproduced with permission.

Turbine–Generator Interface The generator interface is an electromagnetic shaft that connects turbine to the electric generator (alternator). Critical design parameters for selecting the turbine–generator connector include connection mode, efficiency, and cost. Table 4-4 shows the decision matrix for the interface selection process, which was processed in consultation with electrical experts. Direct connection was determined as the most appropriate option.

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Table 4-4.  Decision Matrix for Turbine–Generator Interface. Direct connection Decision factor Cost Efficiency Total

Belt connection

Rope connection

Weight Normalized Weighted Normalized Weighted Normalized Weighted (%) score score score score score score 40 60

0.96 0.96

38.4 57.75 96.15

0.71 0.685

28.40 41.02 69.42

0.82 0.72

32.80 43.20 76.0

Source: Younos (2013).

Turbine Protection To meet the design-head (H) requirement, it is desirable to install the turbine very close to the surface of North Fork Creek that flows in the base of the power house (Figure 4-5). It was noted that several times during the year, the North Fork Creek water level rises up to 1.5 m (5 ft) above the average and causes base-flooding. Therefore, it is necessary to protect the turbine generator from flooding. After considering various options, it was determined that a high-walled watertight caisson turbine housing would best provide the desired protection. Based on cost and other factors, such as material weight and endurance, a watertight plastic caisson was selected to house the turbine.

Electrical Component Design Figure 4-11 shows the electrical components of a modern grid-tied and batterybased micro-hydropower generation system similar to the case study site (Table 4-2). Details of the electrical components design are discussed in the following.

Electric Generator A generator (alternator) with an electromagnet converts mechanical energy into electricity. Based on consultation with experts, a 48VDC (volt direct-current) turbine–generator system was selected for the case study project (Figure 4-12). The system is capable of producing between 6 and 8 A (power outputs up to 2 kW) when running at the designed conditions. Battery Monitor

Turbine

Battery Bank

Charge Controller

Dump Lead

DC Disconnect

Inverter

AC Breaker Panel

To Household Loads

Figure 4-11.  Electric components of a modern micro-hydropower generation and distribution system. Source: Chapter Author.

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Figure 4-12.  Magnet electric generator directly connected to the Turgo turbine wheel. Source: Energy Systems & Design, n.d.; reproduced with permission.

Inverter The inverter converts 48VDC output from the electric generator to standard 120 V AC electricity for consumer use. The AC load includes a wire connection to the Glen Alton lodge and to the electric grid. The electric power company provided a meter that captures electricity delivered and electricity received. This feature allows the Glen Alton site to send excess power to the electric grid (for credit) or receive electricity from the grid in situations when micro-hydropower generation is minimal. Furthermore, the inverter prevents electricity transmission to and from the electric grid during power outages. For a utility-interactive electricity generation plant, such as Glen Alton site, there is a requirement that the inverter be UL1741 compliant. UL1741 refers to the Standard for Interconnecting Distributed Energy Resources with an electric power (grid) system. Based on consultation with hydropower experts and reviewing various vendors, an Outback GTFX3048 DC to AC inverter was selected for this system (Figure 4-13). In addition, an Outback surge protector was used to monitor and manage the system’s power output and load fluctuations and to protect equipment from grid electrical surges and minimize the risk of electricity being back fed to the system.

Controller The electrical loads on the system are dependent on the electricity demand. The controller automatically adjusts the load so that the generator always turns at exactly the right speed and constantly monitors voltage or frequency. A dump-load controller is used to dissipate generated electricity that cannot be used or stored. The dump-load controller installed at the site is an HL-100 Air Heater Dump-Load controller (Wholesale Solar, Mt. Shasta, California) (Figure 4-14). The stand-alone heating/cooling unit at the lodge serves as a temperature regulation unit.

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Figure 4-13.  (a) The outback GTFX3048 inverter and (b) surge protector/monitor. Source: Wholesale SOLAR, n.d.; reproduced with permission.

Figure 4-14.  HL-100 air heater dump-load controller. Source: altEstore, n.d.; reproduced with permission.

In addition, several AC and DC disconnect panels are necessary to properly isolate the system during maintenance or equipment failure. The electric company requires a fused, labeled, and lockable AC disconnect panel at the pole where the meter is installed to isolate the micro-hydropower system from the grid, if needed. In addition, a DC disconnect panel is installed between the battery bank and the turbine generator, which will allow the turbine generator to be isolated during yearly maintenance.

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Battery Bank As was noted, the micro-hydropower system at Glen Alton is both grid-tied and battery based. The electrical output from the generator is connected to a battery bank that allows for generated electricity to be stored in situations where there is no AC load at the lodge or electric grid system (Figure 4-15). At the Glen Alton site, four Universal UB4D 12 V, 200 Ah sealed absorbed glass mat (AGM) batteries, a variant, and an advanced design of sealed valveregulated lead acid batteries (VRLA) were used (Figure 4-16). The system creates a 48 V battery bank with a storage capacity of 200 Amp-hrs. The design storage capacity of the battery bank allows the Glen Alton lodge to be powered for 2 days when there is no electricity generation from the turbine generator.

Battery Overcharge Controller This device detects when the battery bank is fully charged and prevents overcharging of the battery bank (shunt load). A MorningStar Tri-45 controller (Wholesale Solar, Mt. Shasta, California) was recommended to perform this function (Figure 4-17). In addition, a remote temperature sensor (RTS) is connected to the overcharge

Figure 4-15.  Simplified schematic of a battery-based micro-hydropower system. Source: Energy Systems & Design Manual; reproduced with permission.

Figure 4-16.  Universal UB4D 12 V, 200AH sealed AGM battery. Source: altEstore, n.d.; reproduced with permission.

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Figure 4-17.  MorningStar Tri-45 battery overcharge controller. Source: Wholesale SOLAR, n.d.; reproduced with permission.

controller and battery bank. This component is used to improve battery charging in systems that experience temperature variations throughout the year.

Case Study Project Cost A micro-hydropower plant’s capital cost depends on the plant size and site conditions. Table 4-5 shows a summary of cost items for the Glen Alton microhydro project. Detailed costs are documented in the Appendixes A and B.

Cost–Benefit Analysis A brief outline of the cost–benefit analysis for the Glen Alton case study is presented in the following. As shown in Table 4-5, the initial incurred cost/salvage value for the project was $9,900. This is the total project cost because the labor cost is $0 as it was provided by the in-kind support and volunteer work. The Glen Alton system is capable of producing power outputs up to 2 kW. With the estimated system overall efficiency of approximately 60%, the system will continuously produce about 1.2 kW. The yearly operation and maintenance (O&M) was estimated to be $100 to replace bearings in the turbine every year and other potential expenses. The system was tied to the electric grid. The electricity (cost) saving ($) can be based on the system Table 4-5.  Micro-Hydropower Cost Summary at the Glen Alton Site. Cost item Equipment (shipping) Supplies and material Construction* Total cost

Cost ($) 9,471 (450) 420 — 9,900

Source: Younos (2013). *Construction and labor cost was provided as in-kind support by the US Forest Service.

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providing 1,200 W of electricity (credit). The average electricity cost in the United States is about 0.13 $/kWh. Assuming that the electricity cost will increase 15% every year, the projected payback period for the case study project would be 15 to 20 years. In this brief cost–benefit estimation, only the benefits of electricity capture are considered for quantifying the economic value. Note that this type of microhydropower can be a source of personal pride for the owners/community. Those who are environmentally aware and motivated can spend a substantial sum of dollars on installing these types of energy generation equipment as they believe in the cause of renewable energy and environmental issues and, even though, financially the costs do not cover the benefits. These types of “warm glow” benefits or emotional reward are hard to quantify in monetary values and cannot be included in the analysis. Also, the energy costs in the United States are expected to increase and the relatively larger-scale micro-hydropower (i.e., within 60% by volume; carbon dioxide—34% to 38% by volume; nitrogen—1% to 2% by volume; oxygen—470 kW) and heat recovery and the design included the facility to foresee “netzero-energy” operation(s) (Chitikela and Simerl 2017). There is potential for 12,000 new biogas systems to be developed in the United States based on wastewater and livestock manure sources in the country and that could be equivalent to the electricity production of approximately

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68,400 TJ (19 billion kWh) per year. Biogas systems can drive economic growth: distributed energy system development and energy delivery; proven revenue streams; job growth; production of high-quality and concentrated organic fertilizer; avoidance of costs of fossil- or petroleum-based fuel transportation and heat; the available system-payback paves the way for project financing; and there is the availability of RECs and associated demand for this renewable energy. The biogas-distributed energy systems support the local economy and are a win– win to all stakeholders (USDA-EPA-DOE 2014). At a minimum, the biogas-toenergy project(s) development to commissioning includes the following: the preliminary study; RFQs (request for qualifications); selection of a qualified provider; detailed design—conceptual verification, basis of the design, plans, and specifications; environmental permits; cash flow—capital expenditure (CapEx), operational expenditure (OpEx), savings, rebates, grants, and so on; and effective construction or installation. Thereon, periodic measurement and verification of the key performance indicators for the project duration (and beyond) should be conducted (Chitikela and Ritter 2018). Thus, the biogas-to-energy CHP projects are proven: class of renewable; in the control of methane emissions; for local energy independency; and, to meet the triple bottom line (TBL) including resiliency requirements.

SUMMARY Biogas-to-energy is a proven renewable energy system and has successfully been practiced worldwide. Livestock manure, sewage solids, or unstabilized biosolids obtained as raw by-products from wastewater processing; FOG; vegetable and food wastes; and other municipal and industrial highly biodegradable wastes are the feedstocks to a biogas-to-energy CHP system. Biogas is obtained via anaerobic digestion of said feedstocks and comprises a high concentration of CH4, which is a GHG and, therefore, release of methane needs to be controlled and put to use in recovering this renewable energy (and toward making other useful products, as research is ongoing). Many anaerobic digester systems with various configurations are used worldwide and the effective design and O&M of these systems are critical. Biogas conditioning or cleanup is necessary since it contains other than methane, such as moisture, hydrogen sulfide, siloxanes (based on feedstocks) and carbon dioxide; and to suit the downstream use of combustion operations or pipeline-quality supply, as applicable. The applicable local/state/federal regulatory requirements should be followed, such as US 40CFR, Part 503—Standards for the Use or Disposal of Sewage Sludge (and other energy standards, if applicable). The economics of biogas-to-energy systems are sturdy or proven and generate a positive cash flow (with a shorter payback period). Thus, the stabilization of biodegradable and wasted feedstocks via anaerobic digestion and the generation of biogas is a classrenewable since it also provides the feasibility to produce other environmentally friendly byproducts and, fits within the “circular economy.”

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Metcalf & Eddy|AECOM. 2014. Wastewater engineering, treatment, and resource recovery. 5th ed. New York: McGraw-Hill. NBC (Narragansett Bay Commission). 2009. Bucklin point renewable biogas energy feasibility study, and Rhode Island State Office of Energy Resources RI. NREL. 2013. Energy analysis – Biogas potential in the United States. NREL/FS-6A2060178. Golden CO: NREL. OR-DOE. 2018. Biogas and renewable natural gas inventory. SB334 (2017) – 2018 Report to the Oregon Legislature. Salem, OR: OR-DOE. Personal-Experience. 2019. Author’s experience working with various biogas-to-energy CHP systems. Sawyer, C. N., and P. McCarty. 1978. Chemistry for environmental engineering. 3rd ed. 2nd Printing (Singapore). Singapore: McGraw-Hill. Sharvelle, L., and L. Loetscher. 2011. Anaerobic digestion of animal waste in Colorado. Fact Sheet 1227. Fort Collins, CO. Colorado State Extension, Colorado State Univ. Ten-State-Standards. 2014. Recommended standards for wastewater facilities. Albany, NY: Health Research, Health Education Services Division. USDA-USEPA-DOE. 2014. “Biogas opportunities roadmap – Voluntary actions to reduce methane emissions and increase energy independence.” Accessed July 25, 2019. https:// www.usda.gov/oce/reports/energy/Biogas_Opportunities_Roadmap_8-1-14.pdf. WEF (World Economic Forum). 2014. Towards the circular economy: Accelerating the scale-up across global supply chains. Geneva: WEF. Weisberg, P., and T. Roth. 2011. Growing Oregon’s Biogas Industry; A Review of Oregon’s Biogas Potential and Benefits. A White Paper by The Climate Trust and Energy Trust of Oregon (February 2011). Energy Trust of Oregon. Portland, OR. Wright, P. E., and C. A. Cooch. 2017. “Paper Number 1700626: Estimating the Economic Value of the Greenhouse Gas Reductions Associated with Dairy Manure Anaerobic Digestion Systems Located in New York State Treating Dairy Manure.” In Presented at the ASABE Annual Int. Meeting, Spokane WA.

CHAPTER 6

Fuel Cells for Renewable Wastewater Infrastructure Bhuvan Vemuri, Govinda Chilkoor, Jawahar Kalimuthu, Ammi Amarnath, James E. Kilduff, Venkataramana Gadhamshetty

INTRODUCTION Modern infrastructure entails a significant interdependence between water security and energy security. Rapidly changing climate and population growth has resulted in an increasing demand for energy and water (or vice versa), increasing the stress on the water–energy nexus. Figure 6-1 shows the complex interplay of energy production and water consumption, primarily in the context of energy and water exchange between power plants, wastewater treatment plants [or the water resource recovery facility (WRRF)], municipalities, and commercial entities. As shown in Figure 6-1, action taken in one area (energy production) will impact the other (water consumption) (DOE 2006). For example, a 1,800 GJ/h (500 MW) thermoelectric power plant uses nearly 1.14 million m3 (300 million gal.) of freshwater on a daily basis, out of which 97% is returned into the environment (Feeley et al. 2005). Noting that electricity demand in the United States is expected to grow by 41% in the high-economic growth case (annual GDP growth rate = 2.8%) and 20% in the low-economic growth case (annual GDP growth rate = 1.9%) (EIA 2014), we can observe a corresponding increase in water consumption (see EIA 2014 for definitions of the high and loweconomic growth cases). Water is also used for energy extraction; for example, the horizontal drilling and hydraulic fracturing methods that have enabled gas and crude oil production from previously inaccessible shales also entail significant use of freshwater (Shrestha et al. 2017). Energy is required to extract and deliver freshwater for human consumption. Total water withdrawals in the United States have been reported to reach as high as 1.2 trillion m3 [322 billion gallons (Bgal. or BG)] per day (USGS 2015). Nearly

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Figure 6-1.  Interrelation between water and energy. Source: DOE (2006).

41.4% of the water (0.5 trillion m3 or 133 Bgal. per day) is used by thermoelectric power plants, 36.7% (0.45 trillion m3 or 118 Bgal. per day) for irrigation, 12.1% (0.15 trillion m3 or 39 Bgal. per day) for public supply, 4.6% (56.0 million m3 or 14.8 Bgal. per day) by self-supplied industries, 2.3% (28.8 million m3 or 7.6 Bgal. per day) for aquaculture, 1.2% (15.1 million m3 or 4 Bgal. per day) for mining, and the remaining for commerce and self-supplied domestic and livestock operations (USGS 2015). The use of potable water by municipalities and industries, in turn, produces wastewater, which requires treatment by publicly owned treatment works, industrial works, or a WRRF. This wastewater infrastructure is responsible for nearly 3% to 4% of the net energy consumption in the United States and accounts for greenhouse gas emissions of 45 million tons per year (Pirne and Yonkin 2008). In terms of the economic impact, the energy requirements of water and wastewater infrastructure account for 35% of municipal budgets in the United States (Pirne and Yonkin 2008). Among the energy costs, electricity accounts for 25% to 40% of the operating costs for wastewater treatment and 80% for drinking water treatment and distribution (Pirne and Yonkin 2008). Against this background, there is a clear need to minimize both water and energy consumption. On a positive note, the new technologies discussed in this study can help use wastewater as a resource of energy. Anaerobic digestion (AD) is one approach currently used to do this by generating biogas (or biomethane) that can be used as a fuel to generate heat and electricity. However, impurities in the form of carbon dioxide, carbon monoxide (CO), water vapor, nitrogen,

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ammonia, siloxanes, and hydrogen sulfide in biogas reduce the overall efficiency of internal combustion engines. It is also quite expensive to refine and compress biogas (Ong et al. 2014). In addition, AD systems are more effective for treating high-strength industrial wastewaters and sludge, as compared to municipal wastewater. Bioelectrochemical processes can potentially treat low-strength wastewater and simultaneously generate pure hydrogen and methane or directly generate electricity. This study focuses on the use of the emerging fermentation processes or bioelectrochemical processes for rendering a WRRF, a “net-zero” consumer of energy. The hydrogen that can be generated at the WRRF can then be used by a range of established fuel-cell technologies; the power generated by the fuel cells (FCs) can then meet the electricity demands of typical equipment and process operations under the wastewater infrastructure. Figure 6-2 shows typical equipment and power requirements for a 37,850 m3/day (10 MGD) activated sludge municipal WRRF. The equipment include the following: pumps; motors used in screens, grit chambers, skimmers, and sludge rakes; compressors or aerators used in secondary treatment (activated sludge process); lamps used in UV disinfection; motors used for mixing and filter presses in sludge treatment; and heating, ventilation, and air-conditioning (HVAC) and lighting used in buildings and grounds. Figure 6-2 also shows five different classes of FCs that can be used to power various types of WRRF equipment with corresponding power outputs. These include alkaline fuel cells (AFCs), molten carbonate fuel cells (MCFCs), phosphoric acid fuel cells (PAFCs), proton exchange membrane fuel cells (PEMFCs), and solid oxide fuel cells (SOFCs) rated from 0.11 MJ/h to 7.2 GJ/h (30 W to 2 MW) (Kirubakaran et al. 2009). Section 6.2 provides extensive details for each type of fuel cell and its potential uses in wastewater infrastructure. As shown schematically in Figure 6-3, this study discusses a suite of biohydrogen production technologies and fuel-cell designs that can replace energy-intensive secondary treatment processes, improve the efficiency of wastewater treatment, and enable the use of wastewater as a resource for generating energy carriers and electricity. We present an approach that combines dark fermentation (DF) processes to convert the chemical oxygen

Figure 6-2.  A hypothetical example of a 10 MGD WRRF that can use various types of fuel cells to drive typical equipment and process operations. Note: AFC = alkaline fuel cells; MCFC = molten carbonate fuel cell; PAFC = phosphoric acid fuel cell; PEMFC = proton exchange membrane fuel cell; SOFC = solid oxide fuel cell.

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Pumping

Wastewater

Fuel cell

Hydrogen from Biomass

Heat / electricity

Hydrogen gas

Heating and cooling

Lighting Fermentation effluent

Microbial fuel cell

Transportation

Electricity

Treated water

Microbial fuel cell effluent Ultra filtration

Reuse

Figure 6-3.  A conceptual schematic of a biomodule, UF, and a microbial fuel cell for wastewater treatment and energy production. demand (COD) in wastewater into hydrogen, which can be used in FCs to generate heat and electricity [combined heat and power (CHP)]; the fermentation effluent can be further treated in microbial fuel cells (MFCs) to generate electricity. A major opportunity is to replace the activated sludge process with microbial electrolysis cells (MECs) that treat wastewater under anaerobic conditions and simultaneously produce biohydrogen.

HYDROGEN Hydrogen is almost always bonded with other elements, forming compounds such as water, hydrocarbons, and hydroxides in minerals. Unlike oxygen and nitrogen, the gaseous form of hydrogen does not freely exist in nature. A range of chemical, thermochemical, and biological processes generate hydrogen. Unlike fossil fuels, the combustion of hydrogen does not generate greenhouse gases; instead, it yields pure water. The classic methods of hydrogen production rely on energy-intensive processes, including catalytic steam reforming of naphtha or natural gas, gasification of coal, and electrolysis of water. This study discusses the use of biological processes for generating hydrogen from wastewater under ambient conditions.

Biological Processes for Hydrogen Production Hydrogen produced via biological processes is known as biohydrogen. Figure 6-4 provides an overview of four methods for producing biohydrogen.

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Figure 6-4.  Biohydrogen production methods. Light-independent reactions include DF and MECs, whereas light-dependent reactions include photofermentation and biophotolysis.

Dark Fermentation Gram-positive bacteria, including Clostridia spp., can ferment both pure substrates (glucose and sucrose) and complex substrates (corn stover and biomass) to generate biohydrogen. The acetate fermentation pathway yields nearly four moles of H2 per mole of glucose [Equation (6-1)], whereas the butyrate pathway yields only two moles of H2 per mole of glucose [Equation (6-2)]. Operational parameters, such as the hydraulic retention time, pH, and hydrogen partial pressure, can be engineered to achieve the desired fermentation pathway

C 6H12O6 + 2H2O → 4H2 + 2CO2 + 2C 2H 4O2

(6-1)



C 6H12O6 → 2H2 + 2CO2 + C 4H8O2

(6-2)

DF offers high production rates and entails the use of a simple reactor design. Major disadvantages include low yield and accumulation of volatile fatty acids (VFAs). These disadvantages could be overcome by combining DF with downstream processes that require volatile fatty acids as feedstock, including photofermentation, microbial electrolysis, and microbial fuel-cell processes. Furthermore, the VFAs in biohydrogen effluents can be used as carbon substrates in tertiary bioprocesses, such as enhanced biological phosphorus removal (EBPR) processes. DF has been demonstrated on a relatively large scale and for a variety of applications. Wang et  al. (2018) demonstrated the use of DF for generating hydrogen from the space crew’s waste (3.999 mM H2/g waste). Van Ginkel et al. (2005) used DF to treat the wastewater from apple and potato processing plants, producing hydrogen at a rate of 0.7 to 0.9 liter H2 per liter and 2.1 to 2.8 liter H2

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per liter of wastewater, respectively. Han and Shin (2004) used a leaching-bed reactor to generate hydrogen from food waste at a maximum production rate of 04.21 m3 H2 per m3 of waste per day. An anaerobic sequencing batch reactor was used by Mohan et al. (2007) to treat dairy wastewater with a COD removal efficiency of 64% and a hydrogen yield of 1.105 mmol H2/m3/min; also, this team has demonstrated a pilot of 10 m3 DF technology.

Microbial Electrolysis Cells MECs for hydrogen production were first reported in 2005 (Liu et al. 2005). MECs can use pure substrates as well as complex waste streams including DF effluents containing high levels of VFA. These devices use the energy and protons produced by microbial transformation of organic matter, coupled with an additional (small) electric current (Figure 6-5). This current can be driven by a potential of only 200 to 600 mV to produce hydrogen gas in the cathode chamber. This is in contrast to the electrolysis of water, where a potential of 1,210 mV is theoretically required to produce hydrogen gas at a neutral pH, and a potential of 1,800 to 2,000 mV is required under alkaline conditions owing to overpotential of electrodes (Cheng et al. 2002). In an MEC, microbes consume organic matter and produce electrons (e−) and protons (H+). Therefore, hydrogen production in an MEC requires less energy than a traditional electrolysis to produce hydrogen gas. One of the main advantages of MECs is their capacity to treat wastewater and produce hydrogen. Significant progress in the MEC field is observed over the past decade. Heidrich et  al. (2013) demonstrated biohydrogen production (0.015 liter H2 liter−1 day−1) using domestic wastewater in a pilot-scale MEC (120 L). A 1,000 L pilot-scale continuous flow MEC was used by Cusick et al. (2011) to treat winery wastewater, in which they achieved a COD removal efficiency of 62% and biogas (approximately 60% biomethane) of 0.19 liter/liter wastewater/day produced. Call and Logan (2008) achieved hydrogen production (3.12 m3 H2/m3 reactor per day) in a single-chambered MEC (no membrane), which reduces the cost of these systems. However, compared with other biohydrogen production processes such as DF, MECs require higher energy inputs; MECs also require external energy inputs in the form of electric supply (approximately 800 mV). The hydrogen conversion efficiency for MECs is also quite low. Another challenge is that MECs require expensive electrode and membrane materials.

Figure 6-5.  Schematic of a microbial electrolysis cell.

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Photofermentation As shown in Equation (6-3), photoheterotrophic bacteria can generate hydrogen from organic substrates via photofermentation. This process requires an external source of light (Figure 6-6)

C 6O6H12 (glucose) + 6H2O → 12H2 + 6CO2

(6-3)

Unlike DF, anaerobic fermentation of organic waste produces organic acids such as acetic, butyric, and lactic acids, which are converted to hydrogen and carbon dioxide by phototrophic bacteria in the presence of light. Because of low light conversion efficiencies, the hydrogen production rates (in m3) are small, but the yields (in mL/g substrate) are high in this process (Barbosa et al. 2001; Nath et  al. 2008). Recently, the photosynthetic bacterium Rhodobacter sphaeroides has been reported to produce biohydrogen from light, water, and limited nitrogen condition using mixed and single carbon sources (Hakobyan et al. 2019). Microalgae and cyanobacterial are potential renewable resources for biohydrogen production from light and water. Algal biomass can produce H2 in two different ways: (1) extracellular biohydrogen production using specialized hydrogenase genes; and (2) DF using microalgal biomass/residues as substrates for H2 production (Wang and Wan 2009; Wang and Yin 2018). A schematic diagram of photofermentation is shown in Figure 6-6. Although photofermentation offers a higher hydrogen yield than DF, hydrogen production efficiency is about two orders of magnitude lower, and the simultaneous accumulation of oxygen by algae inhibits the hydrogenase enzymatic activity and further limits biohydrogen production (Wang and Yin 2018). Therefore, for the same hydrogen production rate, the photofermentation process requires twice the reactor size compared with DF. Although there are several feedstocks reported for biohydrogen production through photofermentation, actual hydrogen production yields remain much lower than the theoretical maximum value (Su et al. 2009). Photofermentation requires a good reactor design that provides an external light

Figure 6-6.  Schematic of the photofermentation process for hydrogen production.

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source, allows adequate light penetration, and minimizes light attenuation at higher cell densities. Also, the challenges vary with the method of pretreatment, raw material properties, light distribution and density, photobioreactor configuration, and light-, heat-, and mass-transfer properties. Combining DF with downstream photofermentation holds considerable promise and has helped successfully improve overall hydrogen yield (Su et al. 2009).

Biophotolysis Algae and cyanobacteria can generate H2 from water in the presence of sunlight [Equation (6-4)], and this process is known as biophotolysis. The solar conversion efficiencies by this process are quite low. In this process, microorganisms, such as green microalgae or cyanobacteria, use sunlight. These microorganisms contain photosynthetic (PS) pigments such as chlorophyll that can perform oxygenic photosynthesis. Sunlight provides the energy to split oxygen and hydrogen ions from water. The produced hydrogen ions can be combined through direct and indirect routes to produce hydrogen gas. A schematic diagram of direct and indirect biophotolysis is shown in Figure 6-7.

Figure 6-7.  Schematic of biophotolysis: (a) direct biophotolysis, and (b) indirect biophotolysis.

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2H2O → 2H2 + O2

121 (6-4)

Microalgae and cyanobacteria are involved in biohydrogen production through biophotolysis using two distinct pathways, namely, direct photolysis and indirect photolysis. Microalgae, such as Chlamydomonas reinhardtii, use direct biophotolysis and rely on photosystems PSI and PSII along with the hydrogenase enzyme systems (Oh et al. 2013). Cyanobacteria use indirect biophotolysis, with a simultaneous accumulation of electrons/reducing equivalents as carbohydrate energy reserves, along with DF for H2 production. The major advantage of biophotolysis is that it generates hydrogen using water as the sole feedstock. Hydrogen gas produced in this process has a purity of 98% (Kruse et al. 2005). However, in addition to hydrogen, microorganisms produce oxygen, which reduces the overall hydrogen production efficiency.

FUEL CELLS Table 6-1 provides an overview of different FCs that can be used to drive equipment and process operations under water infrastructure. Table 6-1 also provides information on the type of electrolyte, half-cell reactions, and performance parameters including power density and the cost. FCs convert chemical energy into electrical energy by reacting fuel and an oxidant. Hydrogen, methanol, and hydrocarbons can be used as fuels (Wang and Jiang 2017), and ambient air can be used as an oxidant. An FC consists of four different components: (i) an anode, where the fuel such as hydrogen is oxidized, producing protons and electrons; (ii) a cathode, where an electron acceptor such as oxygen is reduced to form water; (iii) a conductive electrolyte that transports the protons from the anode to the cathode; and (iv) an external circuit that electrically connects the anode with the cathode. Although FCs are commonly used to generate electricity, they can also be used to operate in a CHP mode. The thermal energy produced in a fuel cell is on account of electrochemical reactions at the electrodes, overpotential losses, and Joule heating. AFCs are commonly used in spacecraft to generate drinking water. The FCs are commonly classified based on the choice of the electrolyte used in the cell. For example, when phosphoric acid is used as an electrolyte, they are grouped as phosphoric acid fuel cells (PAFCs or PFCs). The type of electrolyte further determines the choice of catalyst, and the operating temperature, which can affect the fuel-cell application. Currently, there are several types of FCs that have their own advantages, limitations, and potential applications. The following sections give a brief overview of the six major fuel-cell designs, each classified based on the electrolyte and fuel used.

AFC

∼1

∼1,800

Oxygen in air

40%–50%

3.8–6.5

50%

CO32− H2, CO, CH4, other hydrocarbons Oxygen in air

1/2O2 + CO2 + 2e−  → CO32−

∼3,000

0.1–1.5

>50%

O2− H2, CO, CH4, other hydrocarbons Oxygen in air

1/2O2 + 2e−  → O2−

H2O + CO32− → H2O +  H2 + O2 → H2O  CO2 + 2e− + 2e−

Lithium and potassium carbonate (LiAlO2) ∼650

MCFC

0.8–1.9

40%

Oxygen in air

H+ Pure H2

1/2O2 + 2H+ +  2e− → H2O

H2 → 2H+ + 2e−

∼200

Phosphoric acid (H3PO4)

PAFC

Parameters

Table 6-1.  Comparison of Different Fuel Cells and Their Application in Wastewater Infrastructure.

∼8,500

∼1

(Continued)

Oxygen in air, potassium ferric cyanide >50%

H+ Organic carbon

1/2O2 + 2H+ + 2e−  → H2O

C12H22O11 + 13H2O   → 12CO2+ 48H+ + 48e−

25

Ion-exchange membrane (optional)

MFC

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Kirubakaran et al. (2009)

Reference

Note: 1 kW = 3.6 MJ/h.

Drawbacks

Expensive platinum catalyst; sensitive to fuel impurities (CO, CO2, CH4, H2S)

High power density; quick start-up

High power density; quick start-up; solid noncorrosive electrolyte Expensive platinum catalyst; sensitive to fuel impurities (CO, H2S)

Advantages

AFC

10–100 kW Pumping; aeration; lighting and heat; sludge-digestion; transportation; portable power

30 W–250kW Pumping; aeration; lighting and heat; sludgedigestion; transportation

PEMFC

Capacity Applications

Fuel cell 100 kW–1.3 MW Pumping; aeration; lighting and heat; sludgedigestion; transportation; portable power Produce highgrade waste heat; stable electrolyte characteristics Corrosive liquid electrolyte; sensitive to fuel impurities (CO, H2S)

PAFC

MCFC

High cost; corrosive liquid electrolyte; slow start-up; intolerance to sulfur

High efficiency; no metal catalysts needed

155 kW–2 MW Pumping; aeration; lighting and heat; sludge-digestion; transportation;

Parameters

1 kW–1.7 MW Pumping; aeration; lighting and heat; sludgedigestion; transportation; portable power Solid electrolyte; high efficiency; generate high-grade waste heat High cost; slow start-up; intolerance to sulfur

SOFC

Table 6-1.  Comparison of Different Fuel Cells and Their Application in Wastewater Infrastructure. (Continued)

Nonreliable influent concentration; pH imbalance; electrode material and performance; membrane fouling; low electricity production, current instability; high cost Do et al. (2018), Logan et al. (2006)

Producing energy while treating organic effluents, and decrease in sludge production

– Replace the aeration process; Pumping; lighting

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Hydrogen Fuel Cells We discuss three major types of hydrogen FCs that can be used to support wastewater infrastructure. As discussed in Section 6.2, the hydrogen gas that is required to drive these FCs can be sustainably generated by biological processes or bioelectrochemical technologies.

Polymer Electrolyte Membrane Fuel Cell Working Principle A polymer electrolyte membrane fuel cell [also known as proton exchange membrane fuel cell (PEMFC)] is used to produce protons and electrons at the anode in the presence of a catalyst (e.g., platinum). The protons and electrons generated at the anode surface flow through the electrolyte (the PEM) and the external circuit, respectively (Figure 6-8), to produce electricity, water, and heat at the cathode. However, PEMFCs require noble metals such as platinum as a catalyst, which increases the initial and operating costs, in part because it is susceptible to carbon monoxide (CO) poisoning if present in fuel (Baschuk and Li 2001).

Figure 6-8.  Schematic of a PEMFC.

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Potential Applications in Wastewater Infrastructure The PEMFC design offers major advantages, including low operating temperatures (50°C to 100°C), lightweight and easy portability, high efficiency, high power density, and low maintenance requirements. PEMFCs are suitable for commercial applications, including use in water reclamation facilities to satisfy plant electricity requirements. As shown in Figure 6-2, it can be seen that the PEMFC has a wide range of power output, from 100 W to 250 kW; therefore, it can be used for virtually every piece of equipment and process at a WRRF, from screening to disinfection, and solids’ processing.

Alkaline Fuel Cell Working Principle AFCs were one of the first FCs developed and were used as the primary source of electricity in the United States’s Apollo space program. As the name suggests, AFCs use alkaline potassium hydroxide (KOH) as the electrolyte. Initially, these AFCs used potassium hydroxide in water as the electrolyte, but because of advancements in technologies in recent years, a polymer membrane (an alkaline membrane) was developed as the electrolyte. Figure 6-9 shows a schematic of the working principle of an AFC. These AFCs produce heat and electrical energy, in which hydrogen and oxygen gas are fed at the anode and cathode, respectively. The hydrogen supplied at the anode reacts with a hydroxyl ion (OH−) to generate water and electrons. The electrons travel from the anode through an external circuit to the cathode, in which electrons react with the supplied oxygen at the cathode to produce water and hydroxyl ions. This hydroxyl ion migrates

Figure 6-9.  Schematic of an AFC.

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through the electrolyte and back to the anode to sustain the anodic reaction (Behling 2012). AFCs offer high performance and efficiencies greater than 60% when combined with heat. AFCs are operated in the temperature range of 50°C to 200°C. However, the disadvantage with AFCs is the formation of carbonate scaling on membrane surfaces due to the presence of dissolved CO2. These carbonate impurities interfere with the electrochemical reactions in AFCs, reducing the overall efficiency and power production. In the case of liquid electrolyte AFCs, parameters including wettability, differential pressure, and corrosion affect the performance.

Potential Applications in Wastewater Infrastructure Because of their operating temperature range, these FCs are easy to start. These FCs have a capacity rating of 10 to 100 kW, which makes these ideal for pumping, aeration, lighting and HVAC, and solids’ processing at a WRRF. Because these are easy to start, they can also be used for transportation requirements within the facilities.

Phosphoric Acid Fuel Cell Working Principle PAFCs use phosphoric acid as an electrolyte. PAFCs are considered the “first generation” of modern FCs and are the first ones commercially used. These FCs use porous carbon electrodes containing platinum as a catalyst. The protons generated at the anode surface flow through the electrolyte (phosphoric acid), and simultaneously the electrons generated at the anode surface move through an external circuit to produce electricity. The electrons and protons meet at the cathode surface to sustain the oxygen reduction reaction (Figure 6-10). Simultaneously, water and heat are produced at the cathode. A typical PAFC is similar to a PEMFC, but instead of a solid polymer membrane, phosphoric acid is used as the electrolyte. The coulombic efficiency of these FCs is approximately 40% (as compared to combustion-based power plants that have approximately 33%), but when combined for cogeneration of heat, the efficiency of these cells reaches more than 85%. Because of the acidic nature of the electrolyte, the components are susceptible to corrosion or oxidation over time. Due to their lower efficiency as compared to other types of FCs, these cells require a higher loading of catalysts to increase their efficiency, which, in turn, increases the cost.

Potential Applications in Wastewater Infrastructure PAFCs produce high-grade waste heat, which can be used for heating requirements of biohydrogen production or digestion processes. These FCs have a capacity of 100 kW to 1.3 MW (range), which makes it ideal for pumping, aeration, lighting and HVAC, and solids’ processing at a WRRF. The main disadvantages of these FCs are corrosiveness of the electrolyte and sensitiveness to fuel impurities.

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Figure 6-10.  Schematic of a PAFC.

Hydrogen and Hydrocarbon Fuel Cells In this section, we discuss two major types of FCs that run on fuels other than hydrogen, and these FCs include carbon monoxide (CO), biomethane (which is the major component of biogas produced in AD), and other hydrocarbons.

Molten Carbonate Fuel Cells Working Principle MCFCs are high-temperature FCs composed of a molten mixture of alkali metal carbonate suspended in a lithium aluminum oxide matrix as the electrolyte, an anode, a cathode, and an external circuit connecting the two electrodes. Figure 6-11 shows a schematic of the working principle of a typical MCFC. The high operating temperature (600°C to 700°C) results in the formation of a highly conductive molten salt carbonate, in which carbonate ( CO32− ) ions provide the ionic conduction. In the anode compartment, hydrogen supplied as fuel reduces the carbonate ions to form carbon dioxide and electrons to produce electricity. CO2 from the anode exhaust moves to the cathode compartment to react with oxygen present in air and the electron supplied from the external circuit to form CO32−

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Figure 6-11.  Schematic of an MCFC. ions. The carbonate ions produced at the cathode are again converted back into CO2 at the anode. As these are operated at a high temperature of approximately 650°C, salt becomes liquid, which enables the movement of carbonate ions and the use of nonprecious metals as catalysts. Unlike other FCs (PEM, AFC, PAFC), MCFCs can use carbon-based fuels, such as natural gas and biogas, which are converted to hydrogen within the fuel cell by a process called “internal reforming,” as shown in Equation (6-5). Because of their high efficiencies (that can reach up to approximately 65%) and high operating temperatures, these FCs are being currently developed for natural gas and coal-based power plants for electricity generation and for use in industrial and military applications. Due to the presence of carbonate ions and the high operating temperatures, the electrodes used in these FCs are vulnerable to corrosion.

CH 4 + H2O = 3H2 + CO

(6-5)

Potential Applications in Wastewater Infrastructure MCFCs can be integrated with WRRFs as the biomethane produced during the solids’ digestion process can be utilized as a fuel in the anode component.

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Because of MCFCs’ capacity to generate electricity in the range of 414 MJ/h to 7.2 GJ/h (115 kW to 2 MW), they can be used to power the equipment and process operations at a WRRF.

Solid Oxide Fuel Cells Working Principle SOFCs produce electricity directly from oxidizing fuels. The materials used for all the components in an SOFC are either ceramic or metal. In an SOFC, oxygen, which is continuously fed into the cathode compartment, undergoes the reduction reaction to produce O2− (Figure 6-12). The electrolyte transports the produced O2− from the cathode to the anode compartment. The fuel in the anode (usually hydrogen or hydrocarbon) reacts with O2− to produce electrons, water, and CO2. The electrons released at the anode pass through an external circuit to the cathode to sustain the cathodic reaction (Huang and Goodenough 2009). SOFCs use a nonporous ceramic compound, such as yttrium-stabilized zirconia, as the electrolyte. These cells are operated at very high temperatures of 800°C to 1,000°C, which eliminates the need for a precious metal catalyst. Similar to MCFCs, these

Figure 6-12.  Schematic of an SOFC.

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SOFCs use carbon-based fuels, such as natural gas and biogas, which are converted to hydrogen within the fuel cell by internal reforming, as shown in Equation (6-3), which also reduces the cost. These cells have an efficiency of more than 50% in converting fuel to electricity, but when the cogenerated waste heat is captured, these can achieve an efficiency of approximately 85%, which is similar to MCFCs. Figure 6-12 shows the schematic and process flow of a typical SOFC.

Potential Applications in Wastewater Infrastructure Because of their high operating temperatures, SOFCs are limited to stationary applications, such as residential facilities, utility power plants, commercial cogeneration, and portable power, making them ideal for operation at a WRRF. These FCs have a wide range of operating capacity, from 3.6 MJ/h to 6.1 GJ/h (1 kW to 1.7 MW), which is ideal for running various WRRF/water reclamation facility infrastructure.

Microbial Fuel Cell The MFC is a bioelectrochemical device that converts chemical energy from organic substrates, such as glucose, into electricity using microorganisms as the catalyst. Generating electricity using microorganisms was first demonstrated by Potter (1911) using Escherichia coli. Recently, the MFC has been getting good traction in the scientific community for its potential as a sustainable wastewater treatment method. Typical components of an MFC include an anode, a cathode, and an ion-exchange membrane (Figure 6-13). The organic matter present in wastewater is oxidized by electrogenic bacteria at the anode surface to generate electrons and protons. The produced electrons pass through the external circuit to reduce an electron acceptor in the cathode compartment, whereas the protons pass via the ion-exchange membrane to the cathode chamber to participate in the redox reaction. It is now well agreed that oxygen is the most suitable electron acceptor as compared to chemicals, such as potassium ferric cyanide, which is toxic to the environment, incurs high cost, and has scalability issues. Recently, air-breathing

Figure 6-13.  Schematic of an MFC.

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cathodes have been developed, which can utilize oxygen present in the air as the terminal electron acceptor, eliminating the use of chemicals and reducing the cost. Even though there are huge advancements in MFCs, their performance is limited by nonreliable influent concentration, pH imbalance, electrode material and performance, membrane fouling, low electricity production, current instability, and high initial cost. Currently, there are few applications of MFCs for commercial or large-scale use, but with increasing demand for an affordable and efficient way to clean water with less sludge by-products, MFCs offer an attractive alternative to existing technologies (Logan et al. 2006).

SUMMARY Fermentation technologies provide an attractive option for generating hydrogen from wastewater, which can drive FCs that support typical equipment and processes operating under wastewater infrastructure. To develop such renewable infrastructure, it is critical to identify and address technological barriers to fuel-cell technology that is solely driven by biohydrogen. Some of the challenges will be those associated with the development of biohydrogen infrastructure (i.e., production, storage, and supply of biohydrogen), durability and reliability of biohydrogen FCs, and end users’ acceptance of the biohydrogen/fuel-cell technology. A series of technoeconomic studies are warranted to assess and compare the viability of different fermentation technologies (DF, photofermentation, microbial electrolysis, and biophotolysis). In the case of MFCs and MECs, technological breakthroughs are required to address fouling challenges faced by materials (catalysts and electrodes) and those pertaining to reactor design. Overall, the biohydrogen/fuel-cell approach discussed in this study provides an exciting route to minimize energy consumption by wastewater infrastructure and drive wastewater processing operations toward a NET-ZERO-energy.

ACKNOWLEDGMENTS The authors acknowledge the funding support from the Electric Power Research Institute (No. 10003325), the National Science Foundation (No. 1736255), and NASA-EPSCoR (No. NNX16A). The authors declare no conflict of interest.

References Barbosa, M. J., J. M. S. Rocha, J. Tramper, and R. H. Wijffels. 2001. “Acetate as a carbon source for hydrogen production by photosynthetic bacteria.” J. Biotechnol. 85 (1): 25–33. Baschuk, J. J., and X. Li. 2001. “Carbon monoxide poisoning of proton exchange membrane fuel cells.” Int. J. Energy Res. 25 (8): 695–713.

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Behling, N. 2012. Fuel cells: current technology challenges and future research needs. Amsterdam: Elsevier. Call, D., and B. E. Logan. 2008. “Hydrogen production in a single chamber microbial electrolysis cell lacking a membrane.” Environ. Sci. Technol. 42 (9): 3401–3406. Cheng, H., K. Scott, and C. Ramshaw. 2002. “Intensification of water electrolysis in a centrifugal field.” J. Electrochem. Soc. 149 (11): 11–172. Cusick, R. D., B. Bryan, D. S. Parker, M. D. Merrill, M. Mehanna, P. D. Kiely, et al. 2011. “Performance of a pilot-scale continuous flow microbial electrolysis cell fed winery wastewater.” Appl. Microbiol. Biotechnol. 89 (6): 2053–2063. Do, M., H. Ngo, W. Guo, Y. Liu, S. W. Chang, D. D. Nguyen, et al. 2018. “Challenges in the application of microbial fuel cells to wastewater treatment and energy production: A mini review.” Sci. Total Environ. 639: 910–920. DOE. 2006. Energy demands on water resources. Technical Rep. No. 201107. Washington, DC: DOE. EIA (Energy Information Administration). 2014. Annual energy outlook 2014: With projections to 2040. Washington, DC: EIA. Feeley, T. J., L. Green, J. T. Murphy, J. Hoffmann, and B. A. Carney. 2005. Department of Energy/Office of Fossil Energy’s Power Plant Water Management R&D Program. Pittsburgh, PA: National Energy Technology Laboratory. Hakobyan, L., L. Gabrielyan, and A. Trchounian. 2019. “Biohydrogen by Rhodobacter sphaeroides during photo-fermentation: Mixed vs. sole carbon sources enhance bacterial growth and H2 production.” Int. J. Hydrogen Energy 44 (2): 674–679. Han, S. K., and H. S. Shin. 2004. “Performance of an innovative two-stage process converting food waste to hydrogen and methane.” J. Air Waste Manage. Assoc. 54 (2): 242–249. Heidrich, E. S., J. Dolfing, K. Scott, S. R. Edwards, C. Jones, and T. P. Curtis. 2013. “Production of hydrogen from domestic wastewater in a pilot-scale microbial electrolysis cell.” Appl. Microbiol. Biotechnol. 97 (15): 6979–6989. Huang, K., and J. Goodenough. 2009. Solid oxide fuel cell technology: Principles, performance and operations. Amsterdam: Elsevier. Kirubakaran, A., S. Jain, and R. K. Nema. 2009. “A review on fuel cell technologies and power electronic interface.” Renewable Sustainable Energy Rev. 13 (9): 2430–2440. Kruse, O., J. Rupprecht, K. P. Bader, S. Thomas-Hall, P. M. Schenk, G. Finazzi, et al. 2005. “Improved photobiological H2 production in engineered green algal cells.” J. Biol. Chem. 280 (40): 34170–34177. Liu, H., S. Grot, and B. E. Logan. 2005. “Electrochemically assisted microbial production of hydrogen from acetate.” Environ. Sci. Technol. 39 (11): 4317–4320. Logan, B., B. Hamelers, R. Rozendal, U. Schröder, J. Keller, and S. Freguia. 2006. “Critical review microbial fuel cells: Methodology and technology.” Environ. Sci. Technol. 40 (17): 5181–5192. Mohan, S. V., V. Lalit Babu, and P. N. Sarma. 2007. “Anaerobic biohydrogen production from dairy wastewater treatment in sequencing batch reactor (AnSBR): Effect of organic loading rate.” Enzyme Microbial Technol. 41 (4): 506–515. Nath, K., M. Muthukumar, A. Kumar, and D. Das. 2008. “Kinetics of two-stage fermentation process for the production of hydrogen.” Int. J. Hydrogen Energy 33 (4): 1195–1203. Oh, Y., S. Raj, G. Jung, and S. Park. 2013. “Metabolic engineering of microorganisms for biohydrogen production.” Biohydrogen, 45–65. New York: Elsevier. Ong, M. D., R. B. Williams, and S. R. Kaffka. 2014. DRAFT comparative assessment of technology options for biogas clean-up. Davis, CA: Univ. of California.

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Pirne, M., and M. Yonkin. 2008. Statewide assessment of energy use by the municipal water and wastewater sector. Rep. No 08-17. Albany, NY: New York State Energy Research and Development Authority. Potter, M. C. 1911. “Electrical effects accompanying the decomposition of organic compounds.” Proc. R. Soc. Lond. Series B 84 (571): 260–276. Shrestha, N., G. Chilkoor, J. Wilder, V. Gadhamshetty, and J. J. Stone. 2017. “Potential water resource impacts of hydraulic fracturing from unconventional oil production in the Bakken shale.” Water Res. 108: 1–24. Su, H., J. Cheng, J. Zhou, W. Song, and K. Cen. 2009. “Combination of dark-and photofermentation to enhance hydrogen production and energy conversion efficiency.” Int. J. Hydrogen Energy 34 (21): 8846–8853. USGS. 2015. “Water use data for the nation.” Accessed July 13, 2020. https://waterdata.usgs. gov/nwis/water_use?format=html_table&rdb_compression=file&wu_year=2015&wu_ category=ALL. Van Ginkel, S. W., S. E. Oh, and B. E. Logan. 2005. “Biohydrogen gas production from food processing and domestic wastewaters.” Int. J. Hydrogen Energy 30 (15): 1535–1542. Wang, J., M. Bibra, K. Venkateswaran, D. R. Salem, N. K. Rathinam, V. Gadhamshetty, et al. 2018. “Biohydrogen production from space crew’s waste simulants using thermophilic consolidated bioprocessing.” Bioresour. Technol. 255: 349–353. Wang, J., and W. Wan. 2009. “Factors influencing fermentative hydrogen production: A review.” Int. J. Hydrogen Energy 34 (2): 799–811. Wang, J., and Y. Yin. 2018. “Fermentative hydrogen production using pretreated microalgal biomass as feedstock.” Microbial Cell Factories 17: 22. Wang, S., and S. P. Jiang. 2017. “Prospects of fuel cell technologies.” Natl. Sci. Rev. 4 (2): 163–166.

CHAPTER 7

Sustainable Desalination Using Renewable Energy Sources Veera Gnaneswar Gude

INTRODUCTION Freshwater production through desalination processes can be achieved by two major physical principles: (1) evaporation/condensation, and (2) separation/ filtration (Gude 2018). Evaporation/condensation processes are known as phasechange operations, whereas separation processes are known as nonphase-change operations. An evaporation process requires thermal energy to form pure water vapor from a saline water source, which is being heated. This water vapor is then condensed on a cooling surface to form freshwater. A small portion of electrical energy is required for fluid transfer and to create pressure conditions suitable for the evaporation process. A separation process involves a membrane, which acts as a physical barrier to separate water molecules from saline water via permeation or diffusion (Gude 2016a). Examples of evaporation/condensation or phase-change processes include solar stills, multieffect evaporation/distillation (MED), multistage flash distillation (MSF), thermal vapor compression (TVC), and mechanical vapor compression (MVC). Separation processes may be based on ion transfer or solvent transfer phenomena as in electrodialysis (ED) and reverse osmosis (RO) processes, respectively. Other emerging hybrid (involving both evaporation and separation principles) desalination processes are membrane distillation (MD) and RO combined with MSF or MED processes (Gude et al. 2010). Phase-change desalination processes require both thermal and electrical energy. Nonphase-change desalination processes require electrical energy only. A comparison of energy requirements for major desalination processes is shown in Figure 7-1.

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Figure 7-1.  Comparison of energy requirements for different desalination processes. Source: Modified after Gude (2018).

DESALINATION TECHNOLOGIES—PRINCIPLES OF OPERATION Multistage Flash Desalination MSF desalination process was the dominant technology in the desalination industry until the year 2000. Its share was around 60% of the total world desalination capacity. Currently, its share in the market is about 30% of the total market and about 80% of the thermal desalination capacity (Gude 2016a). This process consists of a number of flashing stages, a brine heater, pumps, a venting system, and a cooling water control loop. Incoming seawater temperature is increased by passing it through the final heat exchanger (El-Dessouky et al. 1999). Then, it is passed through the brine heater where steam from an external source supplies the energy for the process and heats the seawater in the heat exchanger to the maximum process temperature (80°C to –90°C). Finally, it is released into the first vacuum chamber where the water vapor condenses into a freshwater product on the cooling water control loop, and this operation is repeated in a number of stages to achieve energy recovery and recycling (Younos and Tulou 2005a).

Multieffect Distillation The multieffect distillation (MED) process is different from the MSF process. The operating pressure in the distillation effects is reduced in successive stages so that heat recovery can be achieved in a number of stages (Gude 2015). The heat removed in a previous stage functions as a heat source in the next stage. Feedwater entering the first effect is heated to the boiling point. Both feedwater and heating vapor to the evaporators flow in the same direction. The water that is remaining is pumped to the second effect, where it is once more applied to a tube bundle.

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This process continues for several stages called effects, and there are about 4 to 21 effects in a large desalination plant. In recently designed plants, the feedwater is divided into several parts before entering the flash drums. The rest of the process remains similar to the other design (Ghalavand et al. 2015).

Vapor Compression In this process, the heat for evaporating the feedwater is generated by compressing the vapor. Two methods are used to condense the water vapor and to produce an amount of heat sufficient to evaporate the incoming feed seawater: a mechanical compressor and a steam jet (thermal compressor). In the first method, seawater is evaporated and the vapor is passed through a compressor (Ghalavand et al. 2015). The vapor is compressed, which leads to an increase in the vapor dew point (in this condition, the compressed vapor dew point is higher than seawater boiling point), so it can be condensed by indirect seawater contact, leading to the evaporation of freshwater. The compression ratio should be maintained near unity to increase energy efficiency. In this process, the seawater temperature is held at 100°C (212°F). MVC units are built in a variety of configurations to promote seawater evaporation. The compressor creates a vacuum in the evaporator and then compresses the vapor taken from the evaporator and condenses it in a tube bundle.

Energy Efficiency of Thermal Desalination Thermal energy required for desalination can be provided from different heating sources such as natural gas and steam generated from power plants. The energy efficiency is reported either as gain output ratio (GOR) or as performance ratio (PR). GOR is defined as the ratio of the mass of water produced through a desalination process over a fixed quantity of energy consumed. PR is defined as the mass, in pounds, of water produced by desalination per 1,054 kJ (1,000 Btu) of heat provided to the process (Gude 2015; Ghalavand et al. 2015). This is equivalent to the number of kilograms of freshwater produced per 2,326 kJ (approximately 2,206 Btu) of heat. As shown in Figure 7-1, the MED process has a high GOR or PR compared with the MSF and VC processes. MED is also known to be thermodynamically more efficient.

Reverse Osmosis RO is the most commonly used technology in desalination. In this process, the osmotic pressure is overcome by applying an external pressure higher than the osmotic pressure on the feedwater (brackish/seawater); thus, water flows in the reverse direction to the natural flow across the membrane, leaving the dissolved salts behind the membrane with an increase in salt concentration called brine. Most of the energy consumption for membrane desalination is used for pressurizing the feedwater. A typical large seawater RO plant consists of four major components: feedwater pretreatment, high pressure pumping, membrane separation, and permeate post-treatment. Major design considerations for

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seawater RO plants are the flux, conversion, or recovery ratio, permeate salinity, membrane life, energy consumption, and feedwater temperature. Energy demand by membrane processes is reported as specific energy consumption in kWh/m3 of freshwater produced (Gude 2011). The specific energy consumption has been reduced by almost 10 times over the last two decades as a result of developing energy recovery devices and energy-efficient and highly permeable membranes. Table 7-1 presents a list of desalination processes with process operating conditions and renewable energy applicability. Hybrid technologies such as MD and low-temperature desalination technologies need more pilot-scale demonstrations before they can be considered for large-scale operations.

RENEWABLE ENERGY INTEGRATION WITH DESALINATION PROCESSES Conventionally, desalination processes are powered by energy derived from combustion of fossil fuels, which contribute to acid rain and climate change by releasing greenhouse gases and several other harmful emissions (Gude 2011). Currently, the world’s established desalination capacity is around 10% of the world’s total minimum freshwater demand [basis: a minimum of 100 L/cap/day (26.4 gal./cap/day) for 7.8 billion of the current world population]. It requires 1.63 million tons of oil/day, which may release 179 metric tons of CO2/day. It is clear that freshwater production through fossil fuel-powered desalination technologies is not an environmentally sustainable alternative. It is necessary to develop alternatives to replace conventional energy sources used in the desalination process with renewable ones and reduce the energy requirements for desalination by developing innovative low-cost, low-energy technologies and process hybridizations (Gude 2015). The large quantities of energy required for desalination processes can be provided by various renewable energy sources, as shown in Figure 7-2. The selection process is not simple. Some of the renewable energy technologies such as photovoltaic (PV) and wind turbines have reached maturity, making their application in desalination economical. It should be noted that the desalination processes can function regardless of the source of energy. Heat energy and electricity can be supplied from any renewable energy source. The energy production costs can be improved through process integration and cogeneration schemes (Younos and Tulou 2005b). Renewable energy applications are more favored in regions where they are competitive with other energy production methods. As shown in Figure 7-2, desalination technologies should be integrated with locally available renewable energy sources considering factors such as plant capacity, location, and availability of renewable energy sources. Technologies that require thermal energy can be conveniently combined with locally available renewable energy sources such as geothermal sources (Gude 2016b). However, a proper site and source evaluation

Operating temperature and pressure: 40°C–80°C, atmospheric Source water: seawater/brackish water Recovery Rate: 35%–45% Specific energy consumption: 5,040 kJ/kg Operating temperature and pressure: 40°C–80°C, 1 atm Source water: seawater/brackish water Specific energy consumption: 5,040 kJ/kg; Operating temperature and pressure: 80°C–120°C, 1–2 atm Source water: seawater Recovery rate: 35%–45% Specific energy consumption: 200–350 kJ/kg; 50°C–90°C, 0.1–0.5 atm, Source water: seawater Recovery rate: 35%–45% Specific energy consumption: 150–250 kJ/kg

Solar still

MED

MSF

Multieffect solar still

Description

Process

Solar collectors, solar pond, geothermal source, and process waste heat

Solar collectors and geothermal source

Direct solar energy, solar collectors, PVT collectors, Solar ponds, waste heat source

Direct solar energy, solar collectors, PVT collectors, Solar ponds, and process waste heat

Renewable energy applications

Remarks

(Continued)

Large-scale applications, reliable process, and experience in operations Can be combined with power generation (cogeneration) Cost and energy intensive, not suitable for small-scale applications

Small and rural applications possible, low capital and little maintenance costs, no energy costs Not suitable for large-scale applications because of lower efficiency

Table 7-1.  A comparison of Various Desalination (Membrane and Thermal) Processes and Potential Applications.

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Description

Operating temperature and pressure: 40°C–70°C, 0.1–0.4 atm, Source water: seawater Recovery rate: 35%–45% Source water: seawater Recovery rate: 25%–40% Specific energy consumption: 150–240 kJ/kg Operating temperature and pressure: 40°C–80°C, atmospheric Source water: seawater Recovery rate: 35%–45% Operating temperature and pressure: