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Climatic Impact of Activities
Series Editor Françoise Gaill
Climatic Impact of Activities Methodological Guide for Analysis and Action
Jean-Yves Rossignol
First published 2020 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
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© ISTE Ltd 2020 The rights of Jean-Yves Rossignol to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988. Library of Congress Control Number: 2019952941 British Library Cataloguing-in-Publication Data A CIP record for this book is available from the British Library ISBN 978-1-78630-512-1
Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Chapter 1. Overview of the Scientific Basis for the Greenhouse Effect and Geocycles . . . . . . . . . . . . . . . . . . . . . . . . . .
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1.1. Greenhouse effect . . . . . . . . . . . . . . . . . . . . . . . 1.2. The additional criteria of the emissions in the atmosphere . 1.2.1. The carbon geocycle . . . . . . . . . . . . . . . . . . . 1.2.2. The water geocycle . . . . . . . . . . . . . . . . . . . . 1.3. Answers to exercises in Chapter 1 . . . . . . . . . . . . . .
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Chapter 2. General Methodology for Quantification of a Climate Footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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2.1. Description of the problem . . . . . . . . . . . . . . . . . 2.2. Identification of the greenhouse gases to be included . . 2.3. Quantification of the impact of greenhouse gases on the climate: radiative forcing. . . . . . . . . . . . . . . . . . . . . 2.4. Quantification of the relative climate impact: the Global Warming Potential . . . . . . . . . . . . . . . . . . . . 2.5. Climate impact of gases in relation to their quantity: the emission factor of greenhouse gases . . . . . . . . . . . . 2.6. Impact of greenhouse gas emission processes on the climate: the emissions factor of any material . . . . . . . . . .
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2.7. Impact of an activity on the climate: generalization of the characterization of flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8. Answers to the exercises in Chapter 2 . . . . . . . . . . . . . . . . . . . . . . .
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Chapter 3. Quantification of the Climate Footprint of an Organization: Methodology of the Balance of Emissions . . . . . . . . . . .
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3.1. The various methods. . . . . . . . . . . . . . . . . . . . 3.2. The broad-spectrum greenhouse gas emission balance . 3.3. The system at hand: processes and flows . . . . . . . . 3.4. Data harvesting . . . . . . . . . . . . . . . . . . . . . . 3.5. The case of the regulatory greenhouse gas emission balance in France . . . . . . . . . . . . . . . . . . . . . . . . 3.6. Answers to the exercises in Chapter 3 . . . . . . . . . .
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Chapter 4. Calculation of Emissions . . . . . . . . . . . . . . . . . . . . . . . . .
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4.1. Emissions due to the use of energy . . . . . . . . . . . . . . 4.2. Other direct emissions (excluding energy) . . . . . . . . 4.3. Emissions due to manufacturing of inputs . . . . . . . . . . 4.4. Emissions due to transport of merchandise . . . . . . . . . 4.4.1. Road transport . . . . . . . . . . . . . . . . . . . . . . . 4.4.2. Non-road transport . . . . . . . . . . . . . . . . . . . . 4.5. Emissions due to movements of people . . . . . . . . . . . 4.6. Emissions due to waste treatment . . . . . . . . . . . . . . 4.7. Emissions due to the production of tangible assets . . . . . 4.8. Emissions due to the use of products. . . . . . . . . . . . . 4.9. Emissions due to the end of life of products . . . . . . . . . 4.10. Calculation of uncertainties . . . . . . . . . . . . . . . . . 4.10.1. Emissions due to the incineration of plastic waste (see section 6.1.3.7.3) . . . . . . . . . . . . . . . . . . . . . 4.10.2. Emissions due to transportation of sawdust supplies (see section 6.1.3.5.2) . . . . . . . . . . . . . . . . . . . . . 4.11. Answers to the exercises in Chapter 4 . . . . . . . . . . .
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Chapter 5. Results Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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5.1. Recommended actions. . . . . . . . 5.2. Interpreting balances . . . . . . . . 5.3. Carbon dashboard . . . . . . . . . . 5.4. Answer to the exercise in Chapter 5
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Contents
Chapter 6. Case Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1. Case study 1: brickworks . . . . . . . . . . . . . . . . . . . . 6.1.1. Description of the activity and challenge in the exercise 6.1.2. Activity data and emissions factors . . . . . . . . . . . . 6.1.3. Calculation of emissions . . . . . . . . . . . . . . . . . . 6.1.4. Recap of the quantification of emissions . . . . . . . . . 6.1.5. Recommendations . . . . . . . . . . . . . . . . . . . . . 6.2. Case study 2: vineyard . . . . . . . . . . . . . . . . . . . . . 6.2.1. Description of the activity . . . . . . . . . . . . . . . . . 6.2.2. Challenge in this exercise . . . . . . . . . . . . . . . . . 6.2.3. Specifications about the activity and questions . . . . . . 6.2.4. Activity data . . . . . . . . . . . . . . . . . . . . . . . . . 6.2.5. Answer to case study 2: winemaking industry . . . . . . 6.3. Case study 3: factory for production of animal feed . . . . . 6.3.1. Description of the activity . . . . . . . . . . . . . . . . . 6.3.2. Challenge in this exercise . . . . . . . . . . . . . . . . . 6.3.3. Specific activity data . . . . . . . . . . . . . . . . . . . . 6.3.4. Answer to case study 3: factory for production of animal feed . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Appendix 1. For a Physical Economy . . . . . . . . . . . . . . . . . . . . . . . .
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Appendix 2. Explanation of the Calculation Methods for Emissions due to Transport of Merchandise . . . . . . . . . . . . . . . . . . .
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Appendix 3. Accounting of Emissions due to the Production of Fixed Assets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Appendix 4. Emissions Related to Journeys Made Between the Brickworks and Employees’ Places of Residence: Analysis of Sensitivity to Calculation Hypotheses (Case Study 1) . . . . . . . . . . .
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References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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Foreword
For more than 30 years, the scientific community has been trying to draw the attention of political decision-makers and the wider public to climate imbalance and all the potential consequences that it brings. But the subject is vast and complicated and, above all, requires us to make an in-depth reconsideration of the economic development model that has shaped our societies for 150 years. How can we establish a sustainable reconciliation between issues that are generally perceived to be antagonistic: maintaining growth in the value of wealth of countries and individuals while very significantly reducing (dividing by 4, and more) the general consumption of natural resources, and fossil fuels in particular, all without recourse to radical solutions such as the division of the world population by 2 or 3 and/or a dramatic reduction in individual material wealth and therefore of purchasing power? In fact, this is the key point. Everything, absolutely everything that characterizes our societies today has been made possible due to oil, coal and gas, these fantastic concentrated sources of energy that are easy to exploit and therefore of a totally insignificant cost compared to the services that they provide us with. What is more “normal” today than being able to cross an ocean in a few hours, buy almost everything at the click of a mouse, move at a speed of 130 km/h by simply pressing a button while listening to our favorite music or even being able to live longer and with a better quality of life thanks to progress in medical research. And since we all “stumbled into it naturally when we were young”, how many of us realize that the comfort and way of life that we enjoy every day is possible thanks to the numerous machines that work in our place by “using up” fossil fuels? How many of us realize that the total energy contained in a single liter of oil is equivalent to what an individual in good health would be capable of “producing” with their arms by shifting 6 m3 of earth with a spade every day for 200 days? In total, today, each day
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around the world, the consumption of oil (approximately 100 million barrels) is the equivalent, in volume, of a square-based tower with sides of 100 m and a height of 1 km. This has absolutely no precedent in the history of humanity. Besides the fact that, given the intrinsically non-renewable nature of these fossil resources, this level of consumption can only last for a few decades more at the most, the other consequence is that by burning almost all these fossils, we are adding a massive amount of CO2 into the atmosphere, thus reinforcing the greenhouse effect excessively rapidly with the consequence of a general imbalance of the climate system, which is already in place and which will last for several centuries more. While for the planet, which functions on the time scale of millions of years, this imbalance is a “non-subject”, for the Homo sapiens species that we are, with our time scale of a few decades, this question must be at the top of our “to-do” list. This being the case, given the urgency and the scale of the means that need to be mobilized, it is essential to keep our priorities straight. To act in an effective and pertinent manner, the first thing is to have an inventory of our greenhouse gas (GHG) emissions which is both complete and specific. Today, among those who wish to take action, far too many people and organizations directly aim for an action plan before carrying out any initial diagnostic assessment, or at best having drawn one up based on an extremely cursory diagnosis. It would certainly not occur to you to go and see your doctor and to ask them for a prescription without prior examination or analyses. How is he or she to know if your problem is the heart, kidneys or the stomach? In terms of GHGs, the situation is similar, because the greatest sources of emissions at the scale of a person or of an organization are those that we cannot “see”. Who knows if their favorite smartphone, which sits in their pocket with a weight of a few tens of grams, “weighs” in reality between 30 and 50 kg of CO2? Therefore, it is essential to understand the “overall logic” while ensuring certain subtle points are not missed out, and to have an overview of the situation which has been gained from an objective initial analysis. However, for the subject in question, there are very many individuals and organizations that need to “increase their skills” concerning this issue of the quantification of GHG emissions. Yet higher education establishments or lifelong learning programs that include these questions in their course content are rare. If you are reading this, then we can say a priori that you are interested in the subject or you are at least asking questions about it. Whether you are in formal education or whether that is now, in the past, Jean-Yves Rossignol’s book is a very good starting point for the subject. Its content, simultaneously complete, thorough, precise and accessible, will allow you to establish a solid foundation
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in both methodological and practical knowledge. Moreover, the exercises and case studies proposed throughout the book will allow you to make an immediate transfer from theory to practice, and by doing so will contribute to an effective consolidation of this newly acquired knowledge. In summary, a reference book for all those who truly wish to add this string to their bow and thus play their part in building an effective response to climate change. François KORNMANN President of the Institut de Formation Carbone
Preface
“If we wait until the climate is too inhospitable before we act against the causes of this imbalance, the only guarantee that we will have at that point is that the future will be worse.” Jean-Marc Jancovici, Alain Grandjean C’est maintenant! 3 ans pour sauver le monde This book aims to provide an intellectually independent examination of the impact of activities on climate, in particular targeting students and directors of small- and medium-sized organizations. In France, an institutional method to establish a greenhouse gas assessment exists; the Bilan Carbone® (an English language version of the tools and documentation for this method are available). It includes sophisticated tools and provides full and extremely detailed methodological documentation. The idea behind it was to propose a different perspective, one both precise and global, as well as one obviously compatible with the Bilan Carbone® method. Since 2006, I have taught students about greenhouse gas emission assessments in universities and in various engineering schools, in addition to teaching the Bilan Carbone® itself on behalf of the Institut de Formation Carbone. Given the questions asked and the difficulties that the students encountered, it seemed useful to focus on certain theoretical and methodological aspects in order to participate in a consolidation of the validity of the analyses and calculations used when establishing an assessment. The general sections of this book are a preparation for understanding and using the documentation and the database on the “Bilan GES” platform, which is available online through ADEME, in addition to the information issued by the
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Association Bilan Carbone, which is responsible for the development and promotion of the Bilan Carbone® method. All these methods, and in particular the Base Carbone® provided by the ADEME [ADE 18a, 18b], can be employed by any one of us to carry out a greenhouse gas emission assessment ourselves. However, in order to have access to sophisticated and ergonomic calculation tools, and to obtain the Bilan Carbone® designation, an authorization that can be obtained by taking a training course at the Institut de Formation Carbone is a strict requirement. WARNING.– To sate the curiosity of scientific readers, mathematical workings are presented in some sections of this book. They are not at all essential for an understanding of the assessment methodology, nor are they necessary for practical calculations of emissions. You can purely and simply ignore the mathematical sections that appear arduous. Jean-Yves ROSSIGNOL October 2019
Acknowledgments
I thank, in particular, François Kornmann, president of the Institut de Formation Carbone (IFC), who, since 2011, has given me the opportunity to teach the Bilan Carbone® method to motivated professionals and students as part of the IFC’s integrated educational programs in various higher education establishments. I praise him for his tireless investment in his teaching mission. Concerning this book, I am thankful to him for his informed observations and for the preface that he kindly agreed to provide. I also express my gratitude to his associate, Isabelle de la Calle, for her devoted and agreeable assistance to those dispensing the training courses. Nor should I omit Laurence Nguyen and Élisabeth Kornmann, who carried out this task before her. I mention the training staff who work for the IFC, for the interesting exchanges that we have been able to have during the training sessions, in particular Shafik Asal, Laurie Chesné, Frédéric Chome, Thibault Laville, Rémi Marcus, Vincent Mariel, Olivier Papin and Bertrand Thuillier. I must honor the people that I have met and who have contributed to my own self-improvement, within the Association des Professionnels en Conseil Climat, Energie et Environnement (initially, the Association des Professionnels en Conseil Carbone) – directed successively by Rémi Marcus, Jacques Aflalo and Charles-Adrien Louis – in particular the training staff previously mentioned and Thierry Fornas, Gilles Grandval and Guillaume Neveux, in addition, the members of the South-West branch of the APCC: Patrick Armando, Antoine Audebert, Mathieu Bertrand, Laurent Castagnède and Benoît Mabon.
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I would like to thank the research professors who have entrusted numerous interventions to me at universities and in various engineering colleges, for teaching missions that I designed on the subject of climate change, energy, and the characterization of the climate footprint of activities: Bénédicte Morin (Vocational Bachelor’s Degree in Recycling and repurposing of materials for transport, Université Bordeaux 1, France), Catherine Azzaro-Pantel and Stéphan Astier (Institut national polytechnique de Toulouse, specialization in Eco-energy), Philippe Behra (Institut national polytechnique de Toulouse, specialization in Environmental engineering), Nadine Gabas (École nationale supérieure des ingénieurs en arts chimiques et technologiques), Didier Kleiber and Jean-François Gabarrou (École d’ingénieurs de Purpan), Éric Pinelli, Pascal Lafaille, Benoît Van der Rest (École nationale supérieure agronomique de Toulouse), Adeline Ugaglia and Bernard Del’homme, Hervé Jacob, Benoît Grossiord, Michel Le Hénaff and Antoine Proffit (Bordeaux sciences agro), Aline Duneau (Mastère Spécialisé in QSE, CESI Blanquefort), Roman Teisserenc and the steering group for the Mastère Spécialisé in Eco-engineering (Institut national polytechnique de Toulouse). I would also like to thank Jean-Marc Jancovici [JAN 19], from whom, in 2006, I learnt the Bilan Carbone® method that he designed for ADEME (French Agency for the Environment and Energy Management). He must especially be acknowledged for his precocious and determined engagement in favor of a world that is fit to live in and which is affected as little as possible by climate change, and for his success in instigating an awareness of this subject on a national scale and bringing about dynamic actions. I extend my sincerest gratitude to Jean-Michel Quenisset for re-reading the methodology section of the book and for his pertinent observations of the presentation of the mathematical sections. Lastly, I am grateful to Aline Framarin, meticulous proofreader, as persistent as she is enthusiastic in the detection of imperfections of all kinds, no matter how subtle.
Introduction For a Physical Economy
National economies refer to the gross domestic product (GDP) to evaluate their performance. This indicator represents the total of the added values, meaning the return on the energy input all along the processing chains. The GDP therefore expresses an annual flow. The priority objective for states is to see an increase in this indicator. However, a flow supposes a difference in potential or, stated in a more prosaic manner, “reservoirs” upstream and downstream from the flow. In the context of the economy, these upstream reservoirs are sources of energy, primary materials and biomass, and the downstream reservoirs are biomes that receive the waste from the activity. The former are emptied when the exploited resources are not renewed or when the anthropological pressure exceeds the capacity of the biosphere to renew the resources. The latter fill up when the flow of waste is higher than the capacity of the natural environment to reabsorb these materials. For example, oil is becoming rarer in the Earth’s crust and carbon dioxide that is produced by its use accumulates in the atmosphere. Unfortunately, economic logic incorporates neither the capacity nor the status of the reservoirs. The target that it sets for us is therefore detached from physical possibilities, and the pursuit of an increase in worldwide GDP leads us to a dead end [JAN 09]. This simplistic indicator, which also does not take into account people’s well-being, nor the fairness of redistribution of the wealth produced, must be abandoned, or at least complexified, as suggested by the Stiglitz [STI 09a] commission. A physical indicator based on energy (see Appendix 1) and a method of patrimonial accounting, which expresses the resources consumed and the depreciation of the capacity of natural systems to renew them, in the same way as a depreciation allowance, would be more pertinent to guide humanity on a sustainable trajectory.
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The natural carbon cycle is disturbed by the consequences of human activity, in particular, due to the release of fossilized carbon into the atmosphere in the form of carbon dioxide, a greenhouse gas. The climate system is destabilized by this, and warming, which began in the 20th Century, could be on a scale seen during a change in climate era, but at a pace of an order of 100 times faster. Natural systems and the socioeconomic system could be profoundly affected by this. There is significant inertia in the climate system, and the warming process is not reversible in the medium term. However, the collective will to act could limit warming to a tolerable threshold. This is why international institutions, states and certain private actors have designed and implemented instruments that are intended to direct the economy along a new path which integrates a physical indicator, carbon. It is necessary to install a regulation of the exchanges that takes into account the devaluation of the capital made up of carbonized resources that are not very or not at all renewable, in addition to the capacity of ecosystems to regenerate resources. Several large devices and various tools, more or less generalized, are now in place: the European carbon market initiated by the Kyoto protocol, taxes on carbon dioxide emissions in certain countries, compensation for emissions and analysis methods of the impact of organizations on the climate, in the same way as the greenhouse gas emission assessments. The Kyoto protocol, which came into effect in 2005, imposed on the 38 industrialized countries that had ratified it a reduction in their greenhouse gas emissions by 5.2% over the period from 2008 to 2012, with respect to the reference emissions for 1990. For the second application period (2013–2020), 37 industrialized countries set themselves an objective of an 18% reduction in emissions compared to 1990. The states transfer part of the obligations to their main industries that cause large amounts of emissions, and which are obliged to reduce their emissions each year. The Emissions Trading System (ETS) is a flexibility mechanism that allows companies to choose to invest in procedures with lower levels of emissions or even to buy quotas to relieve themselves of their reduction obligations, which are, in turn, quotas proposed for sale by companies that have exceeded their assigned emission reduction objectives. The law of supply and demand is supposed to optimize reduction efforts from an economic point of view. The theory of the carbon market is alluring, but its implementation and experience have generated disillusionment, or have drifted away from their initial aims [AYK 14, BER 08]. Taxes on emissions are an additional device on the market, applied to carbon dioxide to make their application easier, insofar as it is sufficient to tax fossil energies at the source. Also in this case, a mechanism of flexibility, with receipt “recycling”, would avoid penalizing economically vulnerable actors and would
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reduce other deductions that could affect the dynamic of the economy, such as compulsory contributions based on work. The quota market and carbon taxes are additional devices: the former allows the emission reduction objectives to be expressed quantitatively, but does not provide visibility of the costs, whereas taxation has inverse properties. Carbon compensation consists of quantifying one’s own emissions, of calculating their monetary equivalent at market price and of entrusting the corresponding funds to an organization that is in charge of funding emission reduction projects, under certain conditions of eligibility. The compensation is only really of use for irreducible emissions, after internal improvements of the climate footprint, because if no actors go further than compensating, it is not possible to reach the objective of global reduction. Lastly, methods and tools are freely available to all organizations to take stock of and quantify their emissions due to their activity, in order to design and implement actions to improve the climate footprint and then to measure its effectiveness. With this in mind, this book presents the methodological foundations, according to the least reductive approach possible, to an understanding of the problem of the impact of activities on the climate.
1 Overview of the Scientific Basis for the Greenhouse Effect and Geocycles
1.1. Greenhouse effect During the planet’s recent temperate period, the greenhouse effect has maintained the average temperature of the Earth at 15°C (at sea level), whereas without these gases, it would be just –18°C. The greenhouse effect is beneficial to life. Solar radiation is, depending on the wavelength, more or less absorbed by the atmosphere. Relatively little incident infrared radiation (known as “near” due to the proximity of its range of wavelength compared to that of visible radiation) is absorbed, and instead, this reaches the Earth’s crust which then plays a part in warming (the infrared radiation absorbed by a material is converted into heat). Moreover, all bodies re-emit infrared radiation with a wavelength that depends on their temperature (the higher the temperature, the more energetic the radiation, meaning the shorter the wavelength). In this, we see that the infrared radiation that is re-emitted by the Earth (known as “far infrared”) does not have the same spectral characteristic as that emitted by the sun. It turns out that certain atmospheric gases are high absorbers of this secondary infrared radiation, and then convert it into heat. This is the (simplified) principle of the greenhouse effect (see Figure 1.1). In less than three centuries, due to human activities and, in particular, as a consequence of combustion of fossil energy, the concentration of this greenhouse gas carbon dioxide has increased by 40%. Although its current atmospheric concentration is only 0.04%, the disturbance has been sufficient to trigger a major change in the climate on the scale of the planet [LET 04]. The reason for this is that the climate system is complex, non-linear and subject to non-equilibrium thermodynamics, a foundation for positive feedback where self-amplification phenomena are able to make the system bifurcate to a new climate era [ROS 18].
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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Figure 1.1. Diagram of the greenhouse effect. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
Thus, certain consequences of the warming themselves cause an increase in the greenhouse effect: – the solubility of carbon dioxide decreases when the water temperature increases, causing desorption of CO2 from the oceans; – with atmospheric warming, the increase in vapor pressure of water, the main greenhouse gas, leads, in turn, to an increase in its concentration; – the evaporation of solid methane hydrates encased in permafrost and oceanic sediments releases a powerful greenhouse gas, methane; – along with the warming, the more intense mineralization of organic matter releases extra CO2; – the reduction in the surface area of snow cover leads to a decrease in the reflection of incident infrared, and extra absorption by the Earth’s crust, which re-emits more infrared that can be absorbed by greenhouse gases; – etc.
Overview of the Scientific Basis for the Greenhouse Effect and Geocycles
3
Of course, there have always been climate fluctuations on the planet for various reasons: – cosmological (Milankovitch cycles, of which one process is the variation in the extension of the elliptical orbit of the Earth around the sun); – geological (orogenesis and exposure of calcium silicate which acts with the atmospheric carbon dioxide to create calcium and silica); – biogenic, with plant organism fossilization and the subsequent carbon sequestration (plants synthesize their matter with atmospheric carbon dioxide). Currently, the cause of the warming is anthropogenic, but the problem is the abruptness of the change. The emissions due to our activities are massive and sudden, to such an extent that the ecosystems will not be able to easily readjust. They will be subject to a violent shock, and the disturbance will have destabilizing repercussions on the socioeconomic system. 1.2. The additional criteria of the emissions in the atmosphere 1.2.1. The carbon geocycle
Figure 1.2. Main cyclic processes involving carbon in oceanic environments. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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Climatic Impact of Activities
Figure 1.3. Main cyclic processes involving carbon in continental zones. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
Carbon circulates in the various planetary zones in various chemical forms (Figures 1.2 and 1.3). In particular, it transits through living organisms, of which it makes up a significant part. The retention time varies greatly from zone to zone: from a few minutes to a few millennia for living things; in the order of a century in the atmosphere in the form of carbon dioxide; in the order of hundreds of millions of years in the Earth’s crust in fossil form. EXERCISE 1.1.– Wine-making involves alcohol fermentation of must (squashed grapes). During the fermentation process, driven by yeast, sugar is transformed into alcohol and carbon dioxide is released: C6H12O6 2 C2H5OH + 2 CO2 Glucose Ethanol + Carbon dioxide The fermentation releases around 12 kg of carbon dioxide per hectoliter of must.
Overview of the Scientific Basis for the Greenhouse Effect and Geocycles
5
Motivated by sales strategy choices with the objective of producing better quality wine, a vineyard operator aims to reduce the yield of their vines without increasing the surface area. An intern from an agricultural college points out that by reducing their production in this way, the company will reduce their emissions, but the operator disagrees with this. Who is right? (Answer in section 1.3) EXERCISE 1.2.– How much time does it take for us to generate, by breathing, the equivalent of the climate impact of a 5CV car which travels 1 km, emitting 234 g of CO2? Data: Breathing rate: 15 cycles/min Exhaled volume at rest: 0.5 l/cycle Level of CO2 in the exhaled air: 5% Level of CO2 in the inhaled air: 0.04% Volumetric mass of CO2: 1.87 kg.m-3 (Answer in section 1.3) Carbon migrates in the geosphere on a cyclic pathway, temporarily retained in “reservoirs” [DEN 07, p. 511]. Several cycles affect the carbon. At our human scale, some extend over very long time periods, such as for the carbon cycle of fossilized carbon, or short time periods, such as in the case of a biogenic cycle (cycle related to living things). The length of the cycle is the deciding factor for the current climate, when the carbon goes back through the atmospheric zone in dioxide form (Figure 1.4). Thus, destocking of fossilized carbon enriches the current atmosphere, in which levels of this gas have for a long time been depleted due to the trapping effect of fossilization of living things for long geological periods (long cycle). However, current carbon dioxide emissions due, for example, to plant decomposition (short cycle) do not contribute to modification of the current atmospheric concentration, because an equivalent quantity of carbon dioxide had been extracted from the atmosphere by these plants just before this, during photosynthesis. Since retention time of carbon dioxide in the atmosphere is a century, all complete cycles involving this gas and which are shorter than this period can be considered to have no effect on climate change. However, despite being
6
Climatic Impact of Activities
short, if the cycle is unbalanced, the climate impact does indeed come into play. The inbalance can be a result of an emission of carbon dioxide that is greater than the quantity previously extracted from the atmosphere (for example, combustion of wood from a forest that has not regenerated) or even when the carbon produced by photosynthesis is re-emitted in a chemical form other than CO2 (e.g. methane (CH4)), due to the fact that its warming capacity is higher than that of carbon dioxide. Over the course of past geological eras, different biogeochemical processes have absorbed atmospheric carbon dioxide and have transferred it to other zones, such as the Earth’s crust. Thus, during the Carboniferous era, plant fossilization contributed to this. During the combustion of coal, carbon dioxide is liberated and modifies the current atmospheric composition (Figure 1.4, part a). In the case of a forest floor where there is a balance between the contribution of organic matter via photosynthesis, and mineralization processes carried out by decomposing microorganisms with an associated release of carbon dioxide, the current composition of the atmosphere is not modified (Figure 1.4, part b). In the case of anaerobic fermentation in hydromorphic soils (marshes, rice paddies, etc.), carbon is released in a chemical form (methane) with a Global Warming Potential (GWP) that is 28 times higher than that of the carbon dioxide extracted by photosynthesis at a previous stage in the cycle. The process therefore has an impact on the climate, although it occurs during the short carbon cycle (Figure 1.4, part c). Box 1.1. Three examples that illustrate the carbon cycle: the long cycle of fossilized carbon, which pollutes, and the short cycle of biogenic carbon, with or without an additional greenhouse effect that depends on the chemical nature of the gas
IMPORTANT.– The carbon cycle reveals that it is not emissions of greenhouse gases that are a problem in themselves, but only the emissions that cause an increase in the atmospheric concentration of these gases, with an additional greenhouse effect. Because of misuse of the term, we will refer to additional emissions or nonadditional emissions. TIP.– To determine whether CO2 emissions are additional or not, we need to go back along the carbon path step by step asking ourselves the question: “Where does it come from?” At the start of the path, if we end up at the current atmosphere, the emissions are not additional, but otherwise, they do have an impact on the climate.
Overview of the Scientific Basis for the Greenhouse Effect and Geocycles
a)
b)
c)
Figure 1.4. Impact of carbon emissions on the climate. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
7
8
Climatic Impact of Activities
COMMENT ON FIGURE 1.4.– The impact of carbon emissions on the climate depends on the length of the cycle and on the type of gas (only case (b) does not lead to an additional greenhouse effect). a) Carbon destockage enriches the current atmosphere in CO2. b) The short carbon cycle does not modify the current atmospheric composition if it involves only carbon dioxide. c) The short carbon cycle can increase the greenhouse effect if CO2 is transformed into a type of chemical that has a higher Global Warming Potential (GWP). Figure 1.5 illustrates the conditions required so that combustion of wood does not have an impact on the climate. In order for the wood combustion emissions to not be considered additional, the extraction needs to remain less than or equal to the increase in biomass observed since the previous extraction. On the other hand, deforestation to claim land has a significant impact on the climate because it constitutes carbon destockage (deforestation represents nearly 10% of worldwide emissions).
Figure 1.5. Over a given time period, as long as wood extraction for short lifetime uses (energy, paper, packaging, etc.) remains less than the regeneration capacity of the forest, the greenhouse effect is not increased, because the carbon dioxide emissions of the end-of-life uses of the wood are counterbalanced by photosynthesis
Overview of the Scientific Basis for the Greenhouse Effect and Geocycles
9
1.2.2. The water geocycle Clouds and atmospheric water vapor influence the greenhouse effect by almost 75%. For an educational introduction to the role of water in the planet’s energy system, it is useful to look at the three exercises proposed below, in order. EXERCISE 1.3.– Nuclear power plants use radioactivity as a source of heat to produce pressurized steam which drives turbines and electricity generators. The steam must be condensed by cooling to return the water to the thermodynamic cycle in a liquid state. The cooling is obtained by another water circuit, open or semi-open to the natural environment, through the intermediary of a heat exchanger. Some power plants use cooling towers in which the water that evacuates the heat flows in contact with the atmospheric air before returning to the heat exchanger. A small proportion of the water evaporates in this process, forming immense characteristic plumes of steam above air coolers. This loss, compensated for by extraction in a water course, represents around 2 m3 of water per second (6 liters per kWh of electricity produced) [EDF 13]. Can you quantify the impact of this cooling process on the climate in comparison with the process where water circulates in an open circuit and is simply diverted towards the heat exchanger to cool the system before returning to the river? (Answer in section 1.3) EXERCISE 1.4.– Do the water emissions of combustion engines powered by petrol or diesel generate an additional greenhouse effect? (Answer in section 1.3) EXERCISE 1.5.– Do the trails of condensation produced by commercial airplane engines generate an additional greenhouse effect? (Answer in section 1.3)
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Climatic Impact of Activities
Water circulates between the Earth’s crust and the atmosphere by changing state. Evaporation of water from the ocean, transport by the wind, condensation into rain, infiltration, trickling and flow of watercourses towards the oceans create a cycle which affects the lower part of the atmosphere, named the “troposphere”. For a given average temperature of the planet, the quantity of water in the troposphere is at its maximum, because the partial pressure of water vapor is equal to its vapor pressure for that temperature point. The two liquid and vapor phases are at equilibrium; the input of water vapor shifts the equilibrium towards liquid water, which causes condensation of an equivalent quantity of water: H2O liq. H2O vap.
[1.1]
Consequently, the emission of water vapor at low altitudes, in the troposphere, has no incidence on the atmospheric concentration and does not result in any additional greenhouse effect1. This is obvious for water which evaporates from anthropological installations after extraction from a watercourse, such as in the cooling towers of certain nuclear power plants, because the vapor in question was already in the atmosphere before it fell as rain and supplied the watercourse. But this is also true for new water, synthesized in chemical reactions. Thus, we all know that combustion of hydrocarbons produces carbon dioxide, but we generally forget that the oxidation of hydrogen in hydrocarbons produces water: CnH2n+2 (saturated hydrocarbon) + (3(n+1)/2) O2 nCO2 + (n+1)H2Ovap Synthesized water vapor, new in the geocycle,, causes condensation of an equivalent quantity of water by displacement of the equilibrium [1.1] to the left. On the other hand, if water vapor is introduced into the stratosphere, which is unsaturated, as is done by commercial airplanes, by burning kerosene at an altitude of the order of 10,000–12,000 meters, there is indeed an additional greenhouse effect2.
1 This reasoning is only valid for the short time period of the emission. Over a longer time scale, the warming atmosphere is going to absorb more water vapor because the vapor pressure of water increases with increasing temperature (the equilibrium [1.1] will be shifted to the right). 2 The interface between the troposphere and the stratosphere, known as “tropopause”, is not at the same altitude for all latitudes and seasons and is located between 8,500 and 18,000 meters. Natural phenomena such as powerful ascending air currents in tropical storms can cross the tropopause and introduce water into the stratosphere.
Overview of the Scientific Basis for the Greenhouse Effect and Geocycles
11
Figure 1.6. The lower layer of the atmosphere (troposphere) is the site of the water cycle (the illustration is not to scale, otherwise the thickness of the troposphere would only be around 20 μm on this diagram!)
IN SUMMARY.– For the two main greenhouse gases, only emissions that cause an additional greenhouse effect by increasing the atmospheric concentration need be considered. – Water: - terrestrial and tropospheric sources: never counted; - stratospheric sources: should be counted (which is the case with the demanding Bilan Carbone® method). – Carbon dioxide: the key question is, “where does carbon come from?”: - destockage: source to be counted; - short carbon cycle: emission not counted (no additional greenhouse effect). 1.3. Answers to exercises in Chapter 1 Answer to exercise 1.1 (section 1.2.1) The carbon in carbon dioxide that is released by fermentation comes from must, meaning grapes, and therefore vines. Vines obtain carbon by extracting carbon dioxide from the atmosphere, thanks to photosynthesis. Consequently, a quantity of
12
Climatic Impact of Activities
carbon dioxide that is exactly equal to the amount liberated by fermentation has been extracted a few months beforehand by photosynthesis. The balance is zero, and the emissions from fermentation do not contribute to an increase in the quantity of atmospheric CO2: they have no impact on the climate and are said to be “nonadditional”. The operator is right to insist that the impact of alcoholic fermentation on the climate is not related to the harvested quantities, because it is zero in all cases. For a more detailed consideration of biogenic emissions of wine-making activities, see the case study presented in section 6.2, “Case study 2: wine-making industry”. Answer to exercise 1.2 (section 1.2.1) This question refers to the impact on the climate and not to the quantities of carbon dioxide emitted. The carbon from the carbon dioxide that is released by breathing, in other words, 234 grams in 5 hours and 36 minutes (calculation not necessary for the question to be answered correctly), comes from metabolism, which draws this element from food conveyed via the food chain. Previously, this same carbon is extracted from the atmosphere in the form of carbon dioxide by plants which function by photosynthesis (Figure 1.7). Carbon dioxide emissions due to respiration therefore do not modify the atmospheric concentration and are neutral to the greenhouse effect. On the other hand, the carbon dioxide emissions due to combustion of a fossil fuel change the current atmospheric composition and generate an additional greenhouse effect. From the point of view of the climate, a comparison between the two sources is not relevant if it only takes into consideration the quantities of gases emitted.
Figure 1.7. Certain greenhouse gas emissions have no impact on the climate as they do not cause an increase in the gas concentration, such as in the case of release of carbon dioxide by respiration higher up the food chain, which is balanced by photosynthesis
Overview of the Scientific Basis for the Greenhouse Effect and Geocycles
13
Answer to exercise 1.3 (section 1.2.2) The two cooling principles are equivalent and have no impact on the climate, because water emitted by the air coolers was already contained within the atmosphere, before condensing, precipitating, then dripping and flowing to the power plant. Answer to exercise 1.4 (section 1.2.2) The carbon in fossil hydrocarbons is transformed into carbon dioxide, whereas the hydrogen that saturates carbon chains is oxidized into water (vapor at the temperature of the reaction). This synthesized water is new to the current environment. However, the troposphere, where the water cycle takes place, is saturated (the partial pressure of water vapor is equal to the saturation pressure of water vapor). Under these conditions, the emission of synthesized water vapor does not increase the tropospheric concentration. In fact, it causes condensation of an equivalent quantity of water and does not result in an additional greenhouse effect. Answer to exercise 1.5 (section 1.2.2) Water emissions from the combustion of kerosene in airplane engines occur in the stratosphere, which is not the site of the water cycle and which is therefore not saturated with water vapor. At this altitude, synthesized vapor contributes to an increase in the concentration and consequently generates an increase in the greenhouse effect.
2 General Methodology for Quantification of a Climate Footprint
2.1. Description of the problem The essential question is: How much is the activity of an organization going to increase the temperature of the planet? However, the average temperature of the planet is obviously not an influencing factor in controlling the climate footprint! Two realities of a very different order therefore need to be connected. The planet’s climate is characterized by an average temperature, a global parameter with very high inertia and which depends, in particular, on the atmospheric concentration of greenhouse gases. In addition, any activity is local, occasional, rapidly varying, even temporary and characterized by flows of matter and energy. Thanks to a range of conventions and calculations, these two registers can be correlated in the manner described below. 2.2. Identification of the greenhouse gases to be included Less than 1% of gases in the troposphere contribute to the greenhouse effect. The main ones are presented in Table 2.1.
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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Climatic Impact of Activities
Gas (chemical formula) Water (H2O) Carbon dioxide (CO2) Methane (CH4) Ozone (O3) Nitrous oxide (N2O)
Volumetric concentration in the troposphere (%) 0.3 0.039 (0.028 in 1750) 0.00018 Traces Traces
Table 2.1. Main greenhouse gases that are naturally present in the atmosphere and their relative volumetric concentration
The Intergovernmental Panel on Climate Change [MYH 13] has drawn up an inventory of the following gases, or families of gases, for the purposes of characterization and control of the impact of human activities on the climate (non-exhaustive list); the Kyoto protocol only recognizes the gas or families of gases that are written in bold: – carbon dioxide (CO2); – methane (CH4); – nitrous oxide (N2O); – sulfur hexafluoride (SF6); – nitrogen trifluoride (NF3); – hydrofluorocarbons (abbreviation: HFC; general chemical formula: CnHkFx); – perfluorocarbons (abbreviation: PFC; general chemical formula: CnFx); – hydrochlorocarbons (abbreviation: HCC; general chemical formula: CnHkCly); – chlorofluorocarbons (abbreviation: CFC; general chemical formula: CnFxCly); – hydrochlorofluorocarbons (abbreviation: HCFC; general chemical formula: CnHkFxCly); – hydrobromocarbons (general chemical formula: CnHkBrz); – sulfuryl fluoride (SO2F2). For measurement and reduction of emissions, the following is required: – consideration of the gases that absorb infrared radiation that is re-emitted by the Earth’s crust; – among these, the consideration of those that cause an additional greenhouse effect of anthropological origin.
General Methodology for Quantification of a Climate Footprint
17
Two classes of greenhouse gases immediately become clear: – synthesis molecules which, after dispersal, are certainly new within the geosystem; – natural molecules transferred into the atmosphere from confined stocks (new to the atmosphere only in this day and age). 2.3. Quantification of the impact of greenhouse gases on the climate: radiative forcing Radiative forcing (RF)1 expresses the modification of the energy flow at the level of the tropopause that is induced by the increase in the concentration of a greenhouse gas. It characterizes the ability of the gas to modify the energy equilibrium of the planet. It is power per unit surface area (W/m2). Radiative forcing due to the emission of a greenhouse gas depends on the ease with which the molecule absorbs the infrared radiation that is re-emitted by the Earth’s crust (Aλ), on the atmospheric concentration of the gas ([GHG]) and on its retention time in the atmosphere (τ), in other words, the stability of the molecule. RF = f (Aλ, [GHG], τ)
Figure 2.1. Evolution of radiative forcing as a function of time, with input of a million metric tons of various greenhouse gases into the atmosphere (according to [DEL 05, p. 429]). m0: the mass of gas emitted at the instant 0; ax: the instantaneous radiative efficiency of gas x; τx: the lifetime of molecule x in the atmosphere 1 Radiative forcing was calculated at atmospheric conditions and constant surface areas, but the improvement in knowledge of the system has meant that disturbances can be taken into account in the calculation of radiative forcing, now known as “effective radiative forcing” [MYH 13].
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Climatic Impact of Activities
2.4. Quantification of the relative climate impact: the Global Warming Potential The energy impact of a given quantity of greenhouse gas is the cumulative effect of radiative forcing on a certain time period (in mathematics, this is the integral of radiative forcing). By convention, the time scale considered is a century. The cumulated effect of radiative forcing over 100 years for a given greenhouse gas corresponds to the surface area outlined by the curve of radiative forcing as a function of time and by the graph axes, going up to 100 years (see Figure 2.2). This surface area for carbon dioxide is the reference to which the equivalent surface area of another gas is going to be compared. The ratio of these two surface areas is the Global Warming Potential (GWP) of the gas under consideration. This is a dimensionless measure, which is expressed by a value with no units (in the same way as the density of a solid or liquid material, which has no units, is the ratio of the volumetric mass of this material to that of water). The Global Warming Potential of carbon dioxide is evidently 1:
GWPGHG =
100
0
RFGHG dt /
100
0
RFCO 2 dt
Figure 2.2. The Global Warming Potential of the gas CFC11 is given by the ratio of the orange surface area to the reference surface area (hatched) for carbon dioxide (according to [DEL 05, p. 429]). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
COMMENT ON FIGURE 2.2.– Remark: in fact, this ratio is more important than the diagram would indicate, because the vertical scale of the x-axis is increasingly compressed the higher it goes (logarithmic scale) and visually attributes too much importance to the CO2. The GWP of the CFC11 is 4,660.
General Methodology for Quantification of a Climate Footprint
19
Figure 2.3. If 28 kg of CO2 is required in order to cause the same impact on the climate as 1 kg of methane, then the Global Warming Potential of methane is 28. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
The calculation below is the mathematical expression of Figure 2.2. mx: mass of gas x at time t after emission (m0 at time t = 0) ax: instantaneous radiative efficiency of gas x τx: lifetime of the molecule x in the atmosphere h: time horizon (20, 100 or 500 years)
RFx = a x mx (t) = a x m0exp(-t/τ x ) GWPh (x) =
h
0
RFx dt /
h
0
RFCO 2 dt
GWPh (x) = [-τ x a x m0exp(-t/τ x )]0h / [-τ CO2 a CO2 m0exp(-t/τCO2 )]0h GWPh (x)=a x τ x (1-exp(-h/τ x )) / a CO2 τCO2 (1-exp(-h/τ CO2 ))
Box 2.1. Calculation of the Global Warming Potential from radiative forcing, according to [DEL 05, p. 446–447]
Although the carbon present in biogenic methane (CH4 from anaerobic fermentations, ruminant eructations, etc.) comes from the short cycle, and a molecule of CO2 is required in photosynthesis to synthesize a molecule of CH4, the difference in Global Warming Potential (1 for CO2 and 28 for CH4) leads to an imbalanced climatic effect. Since sheep are ruminants, considerations of methane can be added to Figure 1.7 (Figure 2.4).
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Climatic Impact of Activities
Figure 2.4. Expressed in warming potential, for two CO2 molecules entering the cycle by photosynthesis, outgoing flow due to respiration and eructation is equivalent to 29 molecules of CO2, due to methane (GWP = 28). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
Chemical formula
Lifetime (year) [DEL 05, p. 449]
GWP for 100 years [MYH 13, p. 731–737]
Carbon dioxide
CO2
100
1
Biogenic/fossil methane
CH4
12
28/30
Nitrous oxide
N20
114
265
Sulfur hexafluoride
SF6
3,200
23,500
Gas
NF3
740
16,100
CHF3
260
12,400
HFC-43-10mee (R4310mee)
CF3-(CHF)2-CF2-CF3
15
1,650
Tetrafluoromethane (R14)
CF4
50,000
6,630
Hexafluoroethane (R116)
C2F6
10,000
11,100
Octafluoropropane (R218)
C3F8
2,600
8,900
Nitrogen trifluoride Trifluorohydromethane (R23)
Sulfuryl fluoride Difluoromonochloromethane (R22)
SO2F2 CHClF2
4,090 12
1,760
Table 2.2. Lifetime and Global Warming Potential of some greenhouse gases. For a color version of this table, see www.iste.co.uk/rossignol/climatic.zip
General Methodology for Quantification of a Climate Footprint
21
COMMENT ON TABLE 2.2.– – Yellow background: the main greenhouse gases taken into account by the Kyoto protocol (KP). – Green background: some examples of hydrofluorocarbons (included in the KP). – Blue background: some examples of perfluorocarbons (carbonated chains saturated by fluorine atoms, included in the KP). – Gray background: examples of gases not taken into account by KP (because they are already regulated by the Montreal Protocol which aims to eradicate the molecules that react with stratospheric ozone). Depending on the intensity of the absorption of infrared radiation, the chemical stability of the molecule (lifetime), the atmospheric concentration of the gas, the Global Warming Potential (GWP) can vary over a very wide range (see Table 2.2). The GWP depends on parameters that evolve over time such as the concentration of gas, which is why its value is recalculated and can change periodically. Certain gases that are emitted in relatively low quantities in comparison to carbon dioxide do, however, make a significant contribution as soon as their Global Warming Potential is taken into account (Figure 2.5).
Figure 2.5. Worldwide emissions of greenhouse gases in 2010, expressed in mass of gas (on the left) and in equivalent mass of CO2 (on the right), according to the IPCC [GIE 14, p. 7]. The equivalent mass of CO2 is obtained by applying weightings to the mass of gas, based on the Global Warming Potential (given that the GWP of CO2 is 1, the right and left representations are equal for this gas). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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Climatic Impact of Activities
EXERCISE 2.1.– In the south of the Gironde department in France, the Hostens site is set in a lake-scattered landscape, featuring the remains of former open lignite quarries. Lignite is made up of wood and plant debris from the Tertiary Period, 5 million years old, which was used as a fuel for an EDF thermal power station from 1932 to 1965. It is estimated that 3 million metric tons of lignite has been extracted. The site’s nature leader tells visitors that this fuel is highly polluting, with its combustion emitting 1,800 kg of CO2 per metric ton of lignite. One visitor, who has wood-fired heating, is surprised, because he has noted that the emissions associated with this fuel are only 50 kg CO2e/t. Who is right? Information: mass fraction of carbon in ligneous material: around 50%. (Answer in section 2.8) EXERCISE 2.2.– An anaerobic digestion plant uses biomethane for cogeneration (production of both electricity and heat), thanks to a heat engine and an electricity generator. A faulty weld causes a methane leak. At what threshold level is the impact of the leak on the climate higher than the impact of the combustion of biogas in the engine? Answer 1: a minuscule quantity of methane. Answer 2: a quantity of methane that is 28 times lower than that of CO2. Answer 3: a quantity of methane that is equal to that of CO2. Answer 4: a quantity of methane that is equal to 28 times that of CO2.
For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
(Answer in section 2.8)
General Methodology for Quantification of a Climate Footprint
23
2.5. Climate impact of gases in relation to their quantity: the emission factor of greenhouse gases Defining the emission factor of a gas is simple: all it requires is an expression of the Global Warming Potential. The GWP of biogenic methane is 28, which means that 1 kilogram of methane has the same impact on the climate as 28 kilograms of carbon dioxide. The emission factor of methane is 28 kilograms of carbon dioxide equivalent per kilogram of methane, which is denoted: EFCH4 = 28 kg CO2e/kg CH4 When a mass is involved, the notion of an emissions factor brings us closer to the reality characterizing human activities. However, we are still only looking at greenhouse gases, which is why it is necessary to continue the reasoning, to connect the considerations of these gases to real-life situations and processes at work in the economy. 2.6. Impact of greenhouse gas emission processes on the climate: the emissions factor of any material EXERCISE 2.3.– A manufacturing sector produces 100 metric tons of finished products per year. Its activity depends on other prior activities, starting from the extraction of primary materials (materials and energy), by way of heavy industry, which supplies it with semi-finished products. We suppose that the annual emissions of this sector are as follows for the production of 100 metric tons of products. GHG
Quantity (metric ton of gas)
Extractive industry
CO2
A
Initial transformation industry
CO2 N2O R14
B C D
Final manufacturing industry
CO2 CH4
E F
Calculate the emissions generated by the production of 1 metric ton of products (meaning the emissions factor of the product). (Answer in section 2.8)
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Climatic Impact of Activities
The emissions factor for a material corresponds to all the emissions that are generated by the processes used in its production, expressed in the same “CO2 equivalent” unit, and for a unit quantity of material or energy (a metric ton, a kilowatt-hour or any other relevant units). When the emissions factor (EF) of a material or an energy is known, it becomes simple to quantify the prior emissions (E) that an input flow of this material represents for a quantity Q: E = Q . EF Emissions factors are defined not only for manufacturing processes but also for various other combinations of technical processes, in particular waste treatment, and for unit processes such as combustion or fermentation of materials. At this point, we have almost reached the end of our approach which relates the planet’s temperature to our ordinary local and real activities. The impact of an activity as a whole on the climate remains to be characterized. COMMENT.– The Base Carbone® is the database of emissions factors that is managed by ADEME, freely available online in the top-level domain. The emissions factors for many products are not yet known: one must be able to carry out an estimated calculation according to a defined and solidly argued method (the method and result may be submitted to ADEME to enhance the Base Carbone®). EXERCISE 2.4.– “The shale gas industry releases a smaller quantity of CO2 compared to oil and especially to coal…” [CAI 13]. Check this expert’s statement on the following database by calculating the maximum permissible leak rate during the extraction of shale gas. The calculations are based on a study by Howarth et al. [HOW 11]. The emissions factors for conventional gas and coal are as follows (they are somewhat different from those given by the Base Carbone® [ADE 18b]): – conventional natural gas (low estimate) 2,957 kg CO2e/toe; – conventional natural gas (high estimate)
4,118 kg CO2e/toe;
– coal (open pit mine)
4,005 kg CO2e/toe;
– coal (deep mine)
4,229 kg CO2e/toe.
General Methodology for Quantification of a Climate Footprint
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To maintain coherence, the Global Warming Potential of methane (GWPCH4) for 100 years, calculated by Howarth et al. is 33 (according to Shindell et al. [SHI 09]). Gas leak rate during extraction [HOW 11, Table 2]: – shale gas (min)
2.2%;
– shale gas (max)
4.06%;
– conventional gas (min)
0.31%;
– conventional gas (max)
2.17%.
Lower calorific value of methane: LCVCH4 = 41.61 MJ/kg. (Answer in section 2.8) 2.7. Impact of an activity on the climate: generalization of the characterization of flows The characterization and quantification of the climate footprint of an organization rely on the flows of materials and energy that are necessary for the activity. The flows taken into account are input flows, related to provision of supplies, and output flows, related to products and waste. “Supply of provisions” must be understood in very broad terms: consumables, supplies, raw materials, semifinished products, finished products, liquid fuels, solid fuels, services, transport services, fixed assets, etc. For each flow (index k), there is a corresponding activity data and emissions factor. The activity data leads to quantification of the annual flow (Φk) which, when multiplied by the emissions factor (EFk), returns the quantity of associated emissions. The sum of these emissions for all the flows restitutes the emissions generated by an activity, directly and indirectly (before the activity and after it):
∈=
Φ . EF k
k =1, n
k
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Climatic Impact of Activities
It is important to remember that the emissions generated by an organization include not only the direct emissions, which are produced within organizational scope, such as from a boiler room, a chemical synthesis facility, a livestock farm, etc., but also the indirect emissions, which relate to the activities that the organization in question depends on, such as the emissions generated by the manufacturers for the products bought in, by the organization’s waste treatment, by the transporters that manage deliveries, by the use and end-of-life of sold products. SCOPE OF AN ORGANIZATION’S organization’s emissions includes:
EMISSIONS.–
The overall scope of an
1) direct emissions, attributable to the intrinsic activity; 2) indirect emissions, located outside this scope of activity, for which other parties are responsible, but which are necessary for the organization’s operations.
∈ = direct emissions + indirect emissions
Figure 2.6. The emissions that can be attributed to an organization include the emissions for external activities that are mobilized for operation of the organization. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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Figure 2.7. Summary of reasonings starting with physical characterization of greenhouse gases and leading to quantification of the climate footprint of an organization. For a precise and scientific definition of the measures, refer to radiative forcing [FOR 07, p. 133; RAM 01, p. 353]; Global Warming Potential [RAM 01, p. 385]
2.8. Answers to the exercises in Chapter 2 Answer to exercise 2.1 (section 2.4)
Given that the mass fraction of carbon in lignite is 50%, the extracted quantity of lignite, in other words, 3.106 metric tons, represents 1.5.106 metric tons of carbon. The atomic mass of carbon and of oxygen are 12 g/mole and 16 g/mole respectively (in other words, 44 g/mole of carbon dioxide (CO2)).
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Assuming that it is complete, combustion of 1.5.106 metric tons of carbon releases: E = 1.5.106 × 44/12 = 5.5.106 metric tons of carbon dioxide Related back to a metric ton of lignite, combustion produces: EF = 5.5.106 / 3.106 = 1.83 t CO2/t (1,830 kg CO2/t) The nature leader is right. However, the visitor’s statement is also correct. The significant gap results from the fact that lignite is a fossilized wood (long cycle) whose combustion is a form of carbon destockage, whereas the current combustion of wood from forests in France is compensated for by photosynthesis (short cycle); the emissions factor for wood is, however, not zero, because the exploitation and transformation processes consume fossil energy. Answer to exercise 2.2 (section 2.4)
Methodological reasoning must be applied to each of the sources of emissions: leaks of methane, on the one hand, and release of carbon dioxide due to combustion of methane in the engine, on the other hand. Since it is biogenic carbon (from organic materials that come from plants, directly or indirectly), emissions of CO2 from the engine do not generate an additional greenhouse effect (short carbon cycle) and their contribution is zero. Concerning methane leakage, it does have an impact, although it is the same carbon as in the short cycle, due to the relatively high Global Warming Potential of this gas. Indeed, while from a chemical point of view, the synthesis of a CH4 molecule only requires the absorption of a single molecule of CO2 during photosynthesis, from the point of view of the climate, each molecule of methane that is released corresponds to 28 molecules of CO2. Even the smallest methane leak therefore has an impact on the climate that is greater than the zero contribution of the engine which emits CO2: the correct answer is Answer 1. Answer to exercise 2.3 (section 2.6)
From the point of view of the impact on climate, the total sum of the tonnages of the different gases is not relevant. It is necessary to homogenize the measures by expressing all the quantities in metric tons of CO2 equivalent, taking account of the Global Warming Potential of each of the gases. Using this, we can fill in the table as shown on the following page.
General Methodology for Quantification of a Climate Footprint
GHG
Quantity (metric ton of gas)
Extractive industry
CO2
A
Initial transformation industry
CO2 N2O R14
B C D
Final manufacturing industry
CO2 CH4
E F
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The overall emissions for the collective processes are summarized as:
∈ (t CO2e) = A + B + 265C + 6,630D + E + 30F These emissions correspond to the production of 100 metric tons of finished products. The emissions factor of this product, which represents the unit emissions (in other words, for a metric ton of products), is:
∈ (t CO2e/t) = (A + B + 265C + 6,630D + E + 30F) / 100 Answer to exercise 2.4 (section 2.6)
The emissions factor (emissions per unit quantity) of fossil gas reflects: – the consumption of energy (Wp) for extraction, purification, conditioning, storage and transport (emissions factor: EFWp); – the gas leaks during extraction (Φe); – the gas leaks during the production and transport processes (Φp); – the combustion (C). The symbols SG and NG are used respectively for shale gas and conventional natural gas. Leakage rates of shale gas and conventional natural gases during extraction: α and β respectively. Emissions factor for each type of gas: EFSG = [Φe + EFWp + Φp + C]SG EFNG = [Φe + EFWp + Φp + C]NG
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Since the compositions of the two types of gas are similar (mainly methane), the processes after extraction are identical. For this life phase, the energy used, methane leaks and combustion emissions are identical: [EFWp + Φp + C]SG = [EFWp + Φp + C]NG Therefore: EFNG - [Φe]NG = EFSG - [Φe]SG EFSG = EFNG + ([Φe]SG - [Φe]NG)
[2.1]
Consequently, the emissions caused by the use of a given quantity of shale gas represent those of the same quantity of natural gas, and the impact of the excess of escaped methane during extraction. Calculation of Φe for the production of a metric ton of oil equivalent (1 toe)
The emissions factor of methane released into the atmosphere is 33 kg of CO2 equivalent per kg of methane (GWPCH4 = 33) [SHIN 09]: EFCH4 = 33 kg CO2e/kg, in other words, 33.103 kg CO2e/t The units of measurement must be homogeneous. Since the emissions factors are specified in kg CO2e/toe, the emissions factor of methane must be converted into this same unit: LCVCH4 = 41.61 MJ/kg = 41.61 GJ/t 1 GJ = 23.89.10-3 toe LCVCH4 = 0.994 toe/t EFCH4 = 33.103 / 0.994 = 33,199 kg CO2e/toe For 1 toe of gas, with known leakage rates during extraction (α and β), the escaped quantities are: [Φe]GS = α EFCH4 [Φe]GN = β EFCH4
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Substituting into [2.1], this results in: EFGS = EFGN + (α - β) EFCH4 We shall calculate the gas leakage rate for which the emissions factor for shale gas would be lower than that of other fossil resources (EFF): EFGS < EFF EFGN + (α - β) EFCH4 < EFF α < (EFF - EFGN + β EFCH4) / EFCH4 From the values of the emissions factors and the conventional natural gas leakage rate (β) given in the question, we can deduce the shale gas leakage rate (α) during extraction that must not be exceeded in order for its emissions factor to be lower than that of the fossil fuels to which it is being compared: – data: Scenario
Low estimate
High estimate
EFGN (kg CO2e/toe)
2,957
4,118
β
0.31%
2.17%
– result (constraint on leakage during extraction (α) so that shale gas is less polluting than coal): Low estimate
High estimate
Coal, open pit mine
Scenario
α < 3.47%
α < 1.83%
Coal, deep mine
α < 4.20%
α < 2.56%
The effective range of shale gas leakage rates during extraction is from 2.2% to 4.06%, according to Howarth et al. [HOW 11]. We can therefore not confirm with certainty that “the shale gas industry releases a smaller quantity of CO2 compared to oil and especially to coal…” [CAI 13], because in the worst case scenario, shale gas can be more polluting than all other fossil fuels.
3 Quantification of the Climate Footprint of an Organization: Methodology of the Balance of Emissions
3.1. The various methods On an international scale, in a comparative study of the tools that are intended to give information about the emissions that are made available to companies, the European Commission has listed 90 reporting methods and 30 detailed evaluation methods of the emissions of greenhouse gas [COM 10, pp. 221–222]. In 2008, ADEME [ADE 08] published a summary on the 20 tools and methods of overall evaluation of emissions of greenhouse gases, which are as follows: Bilan Carbone®, California Climate Action Registry, Carbon Impact, Emission Logic, Carbon Management, Carman/Carmon, Emission Manager, Greenhouse Gas Suite, GEMS, GHG Indicator, Greenware’s Greenhouse Gas, Grip, CO2 Navigator, SAP Environmental Compliance, SofiEM, Carbon View, Umberto, Greenhouse Gas Protocol, ISI Tool, Carbon Balance Sheet. In particular, these methods are compared using the following criteria: – methodological orientation (reduction or compensation); – openness of content and methodological transparency; – diffusion potential; – operational characteristics of the solution (rapidity of deployment); – target client for the solution (large companies or all companies); – general type of method (for sites, land areas, products).
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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In the conclusion of the report, ADEME provides an overview of the Bilan Carbone®: “The Bilan Carbone® is a solution which presents numerous advantages in a market where compensation-orientated solutions abound. It is a very general method which allows the emissions of all types of companies, land areas and products (under certain conditions) to be counted in a relatively short space of time, and in a manner that is totally transparent from the emissions factors used and the method used to obtain them. However, deployment methods are a restriction to its development on an international scale” [ADE 08, p. 46].
Figure 3.1. Position of the Bilan Carbone® on ADEME’s diagram of compared method examination criteria [ADE 08]
The ABC (Association Bilan Carbone) [ABC 17] has drawn up an overview of the main tools for use by organizations in their transition to low carbon. This document “aims to provide an inventory of the main approaches to carbon accounting and the support for the energy-climate transition that are available to organizations”. 3.2. The broad-spectrum greenhouse gas emission balance A broad-spectrum balance does not constrain the inclusion of sources of emissions by financial or regulatory criteria, nor by responsibility or localization criteria. Thus, the emissions that are taken into account are not dependent on the ownership of the source, are not subject to an obligation, and can be indirect and far-off. This logic of an extended limit on emissions (selected for the Bilan Carbone®) provides a global perspective of direct emissions for which the organization is responsible and indirect emissions from the activities that it depends on, suppliers,
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transporters, clients, etc. (only in proportion to its dependence, obviously). Any organization from any sector of activity can benefit from establishing a broad-spectrum balance. The generic method is common, but each case presents its own specific points and difficulties, for which the guides by sector that are produced by ADEME will be very useful [ADE 19]. The process of global quantification of an organization’s climate footprint via the consideration of direct and indirect sources leads generally to three major questions for novices: – What is the benefit of including emissions from far-off sources, over which there is no control, in the accounting process? – Doesn’t the extended scope of emissions risk an overlap with other scopes of carbon investigation? – At what point are emissions in the branched structure of mutually dependent actors no longer taken into account?
What is the benefit of including emissions from far-off sources, over which there is no control, in the accounting process? This is, in fact, the most relevant approach to maximize the chances of identifying actions to be put in place to reduce emissions in some way. This logic of global accounting, which tends towards an exhaustive approach, is legitimate in all genuine and voluntarist approaches to the reduction of emissions. Effectively, every organization possesses internal levers which determine changes that are able to affect far-off sources of emissions under the responsibility of third parties. We shall present a few examples. When a company ceases to operate just-in-time production by building up a stock of supplies, it reduces the mobilization of the fleet of a transporter, with fewer rotations and larger vehicle sizes (in one month, daily deliveries of 1.25 metric tons on small lorries with a GVWR of 5 metric tons require 10 times more fuel than a single monthly delivery on a tractor + semi-trailer). When a manufacturing company reduces the overpackaging of its products, this causes fewer emissions in the waste treatment sectors, once the packaging is thrown away by the clients. If, for equivalent cost and quality, a manufacturer can substitute a metal part with a wooden part, then they reduce the carbon impact of their activity by using a material with a lower emissions factor. For a balance to be established, all the sources of greenhouse gas emissions are grouped into categories of the same type, for example, according to the classification
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adopted by the Bilan Carbone® method, with emissions due to the following processes: – use of energy; – processes, fermentations and leaks; – transport of merchandise; – movement of people; – manufacturing of inputs; – waste treatment; – manufacturing or construction of fixed assets; – use of products; – end of life of products. In particular, it may seem surprising or even incorrect to include emissions that are as “far-off” as those generated by the use of products that are produced by a manufacturing company, as part of the balance for this company. Thus, the establishment of a greenhouse gas emission balance for an automobile manufacturer would require the emissions of the fleet of vehicles sold in a year to be estimated for the duration of their lifetime. This inclusion is, in fact, perfectly judicious, because if the manufacturer commits to research and development work to improve the energy output of heat engines, then they determine a lower consumption of fuel for the same number of kilometers traveled by the users. Doesn’t the extended scope of emissions risk an overlap with other scopes of carbon investigation? Another objection that is frequently raised by novices is that certain sources are counted several times. The observation is true (the emissions from delivery transport would be taken into account by a supplier, as well as by their client as part of transport of supplies, during the establishment of their respective balances). If the objective of a balance is to discover the impact of its own organization so that it can act at its own scale, then it does not matter that a given source has already been counted in other balances, which, in general, is also something that is not known. Indeed, on the contrary, if several actors each focus in their own way on a single source of emission, this leads to even greater reductions. Going back to the previous example of the emissions generated by the transport of merchandise, if the
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manufacturer who, let us say, has his or her own fleet of lorries, instructs the drivers to drive economically, and if the client decides to build up a stock by stopping the just-in-time supply, then the effects are combined: the consumption of fuel will diminish and there will be fewer rotations (Figure 3.2). Obviously, if we combine two balances, for example which relate to two different sites to reconstitute the global climate footprint of an organization, then it is necessary to take precautions to identify and remove all redundant counted emissions.
Figure 3.2. Independent actions that relate to a single source of emissions combine their benefit (here, transport emissions are doubly impacted by measures that are very different in nature and are put in place by two connected actors). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
At what point are emissions in the branched structure of mutually dependent actors no longer taken into account? The logic of broad-spectrum accounting causes the feasibility of the balance to be called into question, inasmuch as taking linked activities into account, for example, in previous steps, appears to lead to endless recurrence because a supplier has his or her own emissions, and so on indefinitely. In principle, it would not be right to include previous steps on many successive levels, because the contribution reduces with depth to tend towards zero in an asymptotic curve, as shown in Figure 3.3, insofar as the emissions of partners in a direct descending connection to each other are not included in the successive proportion of the quantities exchanged in the cascade. Therefore, it is not a serious error to shorten the system. In addition, it is not technically necessary to establish “all bearings” balances to characterize the dependence of the emissions of an organization itself on the related activities, because the emissions factors that express them in simple terms are available (quantities of emissions per unit of flow).
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Figure 3.3. Indirect emissions make less and less of a contribution to the balance of emissions of an organization when their indirect aspect increases, along with increasing distance on the branched structure of interlinked activity chains. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
The emissions factors of products are generally not calculated from a combination of balances of all the actors involved, from the extraction of raw materials to final finishing of the products, but instead result from more global studies concerning sectors of activity or branches, characterized by statistics, in particular from the point of view of energy. They allow the previous emissions that are associated with the use of materials or energies to be easily quantified. As we saw in the previous chapter, the emissions are proportional to the quantities at play and to the respective emissions factors; they are thus easily reconstituted without the need for an investigation or for characterization of the climate footprint of supply activities. 3.3. The system at hand: processes and flows Before proceeding with quantification of the emissions, it is essential to construct a correct representation of the system to be studied. A map is created of all the processes that affect the carbon footprint of the organization whose balance is
Quantification of the Climate Footprint of an Organization
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being set up. These processes are internal and external, in the course of the broad-spectrum balance. The processes involve flows, materials, energies, services and greenhouse gas emissions that also need to be represented. An inventory can then be created of the sources of emissions related to the activity in question, with no risk of omissions. The following exercise and the case studies proposed in Chapter 6 will help to reinforce as desired the notions of mapping of processes and flows. EXERCISE 3.1.– Describe the processes and flows of the wood fuel sector throughout the life cycle and identify the sources of emissions. Give the generic expression of the emissions factor for wood fuel (value of annual production: b (metric ton)). We will keep to the main processes without further specification of the product (logs, pellets, chips, sawdust, etc.). We presume that the wood comes from regenerated forests in the country under consideration. (Answer in section 3.6) 3.4. Data harvesting Collecting the large amount of data that is required for calculation of the emissions is a large and onerous stage. It must follow a protocol that is well constructed and as rigorous as possible. Where it is necessary to make requests to third parties to obtain information, their task must obviously be made easy and the risk of error therefore minimized. It is recommended to design and construct personalized tools, such as precise questionnaires in digital format. Data will not necessarily be requested in the format required by the emission calculations, which could oblige those providing the information to make intermediate calculations from the available raw data: by doing this type of calculation ourselves, we avoid basic, hidden errors! However, it is useful to ask the representatives to structure the data to avoid an excessive and risky deciphering task. A happy medium must be sought between two extremes, and the collection tool that is designed and made available to the people contacted will guide them along the right path. Any indications that can contribute to evaluation of the uncertainty should also be collected: does the recorded data result from a measurement, a reading? From what source of information? According to an estimate, established by whom (to establish the degree of reliability)? The list of questions goes on. Increased vigilance is also required for orders of magnitude (confusion between MWh and kWh is easy to detect, depending on the size of the organization). This type of error very easily slips into the procedures and has heavy consequences. Cross-checks are also very valuable (an error can obviously be suspected if the flow of waste is greater than the flow of inputs! The idea of making comparisons must also be applied… Many other less
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Climatic Impact of Activities
basic anomalies can be uncovered in this way. When establishing a Bilan Carbone® for clients in the past, I have, on occasion, identified an anomaly in the consumption of electricity by cross-checking data, which revealed to the organization that had requested the analysis that a lessor was making them pay the bill in its entirety, for premises that were shared by two organizations and without individual meters! When the data are not easily accessible and indicate that a significant amount of work is needed, it is useful to make an estimate of the emissions to measure the stakes at hand. If, in the context of other emission items, they are insignificant, it is reasonable to make do with an estimate, bearing in mind that this must be based on solid reasoning. An estimate is not an approximate quantification; it is the development of a rigorous, reliable and communicable justified reasoning! It is also beneficial to keep the initial data, the original documents and all the details of data processing and intermediate calculations, to make it easier to return to them later as part of a discontinuous working process, for retrospective checks, etc. This precaution can extend to the point of recording “= 2 × 3” in a cell in a digital calculation tool, instead of “6”. Effectively, if there is a requirement a few months later to go back through the different steps to the source, one could have doubts about the origin of the “6”, whereas with the detail of the operation, there is an immediate reference for significant values. Once the data is collected, verified and put into the required format, we proceed to calculate the emissions, which is the subject of Chapter 4. 3.5. The case of the regulatory greenhouse gas emission balance in France Article 75 of law no. 2010-788 dated July 12, 2010 relating to national commitment to the environment, known as “Grenelle 2”, modifies Chapter 9 of heading 2 of volume 2 of the Environmental Code by adding a section 4 entitled “Balance of greenhouse gas emissions and territorial climate-energy plan”, which stipulates: “Art. L. 229-25. – The following entities are required to establish a balance of their greenhouse gas emissions: 1) legal entities subject to private law that employ more than five hundred people; 2) in overseas regions and departments, legal entities subject to private law that employ more than two hundred and fifty people and carry out the activities defined in (1);
Quantification of the Climate Footprint of an Organization
41
3) the State, regions, departments, urban communities, conurbation authorities and municipalities or groups of municipalities of more than 50,000 inhabitants, in addition to other legal entities subject to public law that employ more than two hundred and fifty people. The State and the people mentioned in sections (1) to (3) include with this balance a summary of the actions that are envisaged to reduce their greenhouse gas emissions. This balance is made public. It is updated at least every three years” [JOU 10]. EXERCISE 3.2.– A municipality employs 263 agents to manage a municipality of 49,834 inhabitants: does the regulatory obligation to establish a greenhouse gas emission balance apply? (Answer in section 3.6) The regulatory balance method is modeled on the ISO 14064-1 method, which stipulates conditional inclusion of emissions. The obligation applies to entities that are “under control”1. The notion of control is based, at the declaring party’s choice, on either financial control (the ownership of a property confers financial control of it) or on operational control (control of implementation confers operational control). It is an all-or-nothing option: a legal entity that has joint possession of an establishment, in the proportion of 25% of the share capital, for example, does not have financial control of it and would not be affected by the regulatory obligation, if the “financial control” option is chosen. The criteria of control thus allow the scope known as “organizational”, targeted by the obligation to declare emissions, to be outlined. Within this scope, the operational scope then needs to be distinguished, which is made up of all the assets under control that generate emissions, reduced to the following cases: – direct emissions: - stationery combustion sources; - mobile heat engine sources; - processes (except for energy sources);
1 The alternative to the criteria of control stipulated in ISO 14064, meaning accounting of emissions in proportion to the share capital held, was not selected by the legislator for France.
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- leaks of greenhouse gases (fermentations, refrigerant gases, etc.); - from biomass (ground and forests); – indirect emissions related to consumption: - of electricity; - of steam, heat and cold. It is not compulsory to declare all other types of sources of emissions listed in section 3.2 as “the broad spectrum greenhouse gas emission balance”, such as those associated with the production of inputs, with waste treatment, with the production or construction of fixed assets, or with the use and end of life of products. The same is true for sources to be declared a priori, but over which no control is exerted (see exercise 3.3). The scope of emissions under consideration in the regulatory framework is very restricted and does not allow an optimal action plan to be put in place to reduce an organization’s climate footprint. A better approach consists of establishing an exhaustive balance according to the principles presented above and extracting from this the information required by regulations if the organization is subject to an obligation.
Figure 3.4. Scope, situation and type of the sources of emissions to be declared on the regulatory balance. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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For more information about the regulatory greenhouse gas emission balance, the relevant pages on the ADEME [ADE 18d] website and basic method guides [MEE 16a, MEE 16b] can be consulted. EXERCISE 3.3.– A company in south-west France that employs 525 people (equivalent of full-time contracts) uses a service provider for the operation and maintenance of technical infrastructure including an emergency generator. The service provider provides this equipment and is responsible for its operation and maintenance. For the company’s regulatory obligation to declare the sources of emissions, the option of operational control is selected. Consider the status of the generator for the declaration of its emissions. (Answer in section 3.6) 3.6. Answers to the exercises in Chapter 3 Answer to exercise 3.1 (section 3.3) Non-specific sources of emissions, such as the means of transport used by employees, do not feature on the diagram. The categories are wide-ranging to simplify the representation. Thus, the nature of the waste and the various inputs are not specified (technical and administrative consumables, mechanical parts, supplies for packaging wood, etc.). We suppose that all transformation machines (saws, shredders, etc.) operate using electricity. Over the entire life cycle, the system associated with the wood transformation company, as well as the major processes, the flows of material (respective quantities qi) and emissions, are presented in a diagram below. We have EFi the emissions factor for each flow (fuel, electricity, inputs, etc.). AP designates the flow of CO2 absorbed by photosynthesis and EC the emissions from the combustion of wood. The emission balance for the combination of processes is expressed by: E = ∑ qi EFi + EC – AP
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Figure 3.5. Schematic map of processes, flows and emissions of the wood–energy sector. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
Insofar as the wood comes from regenerated forests, the combustion emissions correspond to the extraction of photosynthetic carbon dioxide and do not lead to an additional greenhouse effect: |EC| = |AP| E = ∑ qi EFi On the company’s balance, delivery transport emissions are indeed included but, by convention, they are not included in the emissions factor for the product (if a client establishes their own balance, they could easily calculate the emissions related to the production of wood in proportion to the quantity that they would buy and they should add to this the emissions from supply transportation in the specific case that concerns them). The emissions factor for the wood fuel is therefore:
7 EFwood = qi EFi / b 1
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Answer to exercise 3.2 (section 3.5) Local and regional authorities are legal entities subject to public law. In relation to them, article L. 229-25 of the Environmental Code states that the obligation for a greenhouse gas balance is conditional on the population numbers (more than 50,000 inhabitants). The municipality under consideration is therefore not required to establish a greenhouse gas emission balance. Answer to exercise 3.3 (section 3.5) Here, the case is of a legal entity subject to private law. Since the workforce numbers more than 500 employees, the company is required to construct a regulatory balance. The generator supplies electricity thanks to a heat engine that consumes a fossil fuel. This is indeed a fixed source which directly emits carbon dioxide. However, since the selected option is operational control, held by a third party which ensures the operation and maintenance of technical infrastructures, emissions by the apparatus do not need to be declared by the company in question.
4 Calculation of Emissions
The emission accounting methods (Greenhouse Gas Protocol, ISO 14064, Bilan Carbone®, etc.) arise from the generic calculation methods presented in Chapter 2 (Figure 2.7). Using the general typology presented below, they organize the calculation of many activity-related emission sources. These categories provide a view by sector of the climate footprint, which is useful for designing a “low carbon” strategy. However, the various methods can provide details of sub-categories of sources to group them together according to specific criteria. With a view to optimizing the pedagogical approach, the general typology presented here is not as finely detailed as in the standard methods. IMPORTANT.– For this chapter, the numerical values of the emissions factors are valid for France. In the case of other countries, they will need to be adapted. 4.1. Emissions due to the use of energy Emissions related to the use of combustible substances and fuels for immobilized machines (vehicles fall into the categories dedicated to the transport of merchandise and to the movement of people) are due to two contributions: – direct emissions from combustion (CO2); – emissions from production processes and conditioning of combustible substances and fuels (named “previous processes” or, in shorthand, “previous”).
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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The emissions factor of a combustible energy adds two components together: EF combustible energy = EF previous + EF combustion As an indication, here are a few values of emissions factors given by the Base Carbone® [ADE 18b]. Take care not to get confused, because some figures apply to Europe in general and others specifically to France, and numerous values are proposed for the same energy as a function of the unit of quantity: – EF petrol (combustion + previous): 2.808 kg CO2e/liter; – EF non-road diesel (combustion + previous): 3.165 kg CO2e/liter; – EF domestic fuel oil (combustion + previous): 3.251 kg CO2e/liter; – EF heavy fuel oil (combustion + previous): 3.283 kg CO2e/liter; – EF natural gas (combustion + previous): 0.243 kg CO2e/kWh LCV; – EF butane (combustion + previous): 3.437 kg CO2e/kg; – EF propane (combustion + previous): 3.457 kg CO2e/kg. The emissions related to the supply of electricity need to be counted in this group. In France, the emissions factor of electricity from the network (mix of energy from various producers) is: EF = 0.0647 CO2e/kWh (2016 value) The emissions include an increase of the order of 10% due to losses from the Joule effect along the entire length of cables in the distribution lines in the network. This increase is legitimate, because even if it is not consumed by the user, the lost electricity is still produced by the power plants. For this group that is associated with the use of energy, a range of calculation methods are possible, by use, by producer, by unit surface area of buildings, etc.: refer to the methodology documentation and Base Carbone® provided by ADEME [ADE 18a, ADE 18b]. Other units of quantity can be used: kWh (kilowatt hour), toe (metric ton of oil equivalent), GJ (giga-Joule), etc.: we can convert the units or refer to the database of emissions factors [ADE 18b] which proposes values in all standard units.
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49
4.2. Other direct emissions (excluding energy) These emissions take place in situ, except for combustion emissions, which have already been counted in the previous group, and result, in particular, from: – leaks (e.g. refrigerants from cold production installations); – chemical reactions (e.g. liberation of carbon dioxide by the reduction of calcium carbonate to produce lime); – enteric fermentation in ruminants, which eruct methane, a gaseous product of the metabolism of micro-organisms that are present in their digestive tract; – anaerobic fermentation of organic matter, which liberates methane, emitted by micro-organisms which decompose matter in anaerobic conditions (in aerobic conditions, other micro-organisms intervene and liberate carbon dioxide (be careful of the non-additional nature of the emission, in this case)); these emissions can result from long storage of organic waste, badly managed compost (not correctly aerated), methane leaks from a methanization installation, etc.; – emanations of nitrous oxide due to the activity of micro-organisms which take in nitrogen from soils (application of nitrogen fertilizers intensifies this process); – etc. For the calculations, consult the documentation and the database of emissions factors provided by ADEME [ADE 18a, ADE 18b]. 4.3. Emissions due to manufacturing of inputs Quantification of each flow of material (raw materials, semi-finished products, finished products, consumables, supplies, parts, etc.) for the time duration of the balance (generally one year) allows the emissions from manufacturing to be calculated using the corresponding emissions factors (see the documentation and Base Carbone® provided by ADEME [ADE 18a, ADE 18b]): Ei = Qi . EFi Services are treated as inputs. Their emissions are estimated on the basis of emissions factors normalized to 1,000 euros of provided services [ADE 18a, ADE 18b]. A single emissions factor is applied for various services, grouped into categories as a function of the quantity of matter and energy that they require (e.g. the emissions factor for the services provided by a lawyer is lower than for a printer).
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4.4. Emissions due to transport of merchandise Calculation of emissions due to the transport of merchandise can be easy when the fuel consumption is a known quantity. It is, in general, much more arduous, in particular, when dispatching is operated by a third-party transportation company. This difficulty is compounded by the evolution of the calculation method that is recommended by ADEME with the aim of adjusting it to the constraints imposed by the regulatory greenhouse gas emission balance method. This evolution is expressed, for the moment, by the unavailability of a previous calculation tool, for combined road transport when transporters are used. This is why, when the quantity of fuel consumed specifically to carry a given merchandise is not known, two possible methodological approaches are presented below: – using the online data of the current Base Carbone® [ADE 18b] (section 4.4.1.2); – using a previous approach (section 4.4.1.3), based on the calculation method initially designed by Jean-Marc Jancovici, which differs from the current approach, in particular, in the proposed typology of lorries, but which made quantification of the emissions easy in the most complex cases thanks to a dedicated calculation tool. On the basis of this, an extension has been developed by the author (see section 4.4.1.3.3 the tab “TKm2”) to free ourselves from this institutional calculation tool, which is not necessarily available to us in its previous version, and which no longer has an equivalent. 4.4.1. Road transport 4.4.1.1. FC method: calculation of emissions using fuel consumed (FC) When the quantity of fuel consumed in the transport of merchandise is known, the calculation of the corresponding emissions becomes relatively easy and precise (EFdiesel with previous = 3.158 kg CO2e/liter [ADE 18b]). 4.4.1.2. Method based on the current Base Carbone® (since 2018) The Base Carbone® [ADE 18b] provides values of unit quantities of fuel and emissions factors for various categories of lorries, according to several data input methods: per metric ton.kilometer of merchandise (see below for the meaning of this unit) or per vehicle.kilometer (the term “vehicle” is sometimes omitted, and the unit is reduced to “kilometer”, for a single truck or when the kilometerage of several vehicles can be cumulated), depending on whether the question is approached by focusing specifically on the merchandise or on the vehicles that are in service. The calculation itself is simple, consisting of a multiplication of the correct activity data (kilometer or metric ton.kilometer) by the unit consumption of
Calculation of Emissions
51
fuel, or by the emissions factor corresponding to the category of mobilized truck. It is thus possible to reconstitute the emissions generated by the complex route taken by merchandise conveyed to a transporter, which can require several categories of vehicles for collection, transportation between depots, and distribution. However, if the data required for the truck categories involved proves too difficult to collect, or if the merchandise is mixed with others in an unknown proportion, you can follow the procedure described below, knowing that the categories of truck differ from the current typology of the Base Carbone®. 4.4.1.3. Method based on the previous Base Carbone® (before 2018) Depending on the available data, you have a choice between the various calculation methods that are presented below. Justification of the values and equations is given in detail in Appendix 2. A summarizing logic diagram is proposed in section 4.4.1.3.4 to facilitate the selection of a calculation method from the three that are summarized below (VKm, TKm1 and TKm2). NOTE.– Dimensions and units used to describe the transport of merchandise. The basic unit for estimation of consumptions is the metric ton-kilometer, denoted “metric ton.kilometer”, or “t.km” in the shortened form. The dot between the “t” and “km” indicates that the dimension in question is the product of a weight and a distance. Many students are thrown off course by this dimension, which they sometimes confuse with metric tons per kilometer (t/km). It is justified by the fact that fuel consumption is proportional to tonnage and kilometerage (Figure 4.1). The unit vehicle.km follows the same logic of double proportionality, relative to the number of mobilized vehicles (or to the number of rotations carried out by a single vehicle) and to the distance traveled by each one in kilometers.
When the quantities of fuel consumed are not accessible, a distinction can be made between two cases for the calculation of emissions, depending on the knowledge that we have of the transport conditions: – calculation based on the kilometerage of the truck (VKm method); – calculation based on the tonnage of merchandise and the distance traveled (TKm method). The second case is subdivided into two options (TKm1 and TKm2), depending on whether or not a single delivery makes use of several lorries of different categories on sections of journeys that are known or not known.
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Climatic Impact of Activities
Figure 4.1. Qualitative justification of the unit metric ton.km: as an initial approximation, the consumption of fuel is proportional to the tonnage and to the kilometerage, therefore to the product of the two dimensions (unit consumption is exaggerated for this diagram, to simplify the explanation, which at this point is only based on the calculation principle, and not on realistic quantities)
Figure 4.2. Main types of trucks (according to the former typology of the Base Carbone®)
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53
COMMENT ON FIGURE 4.2.– The reality is more complex, because the number of axles affects the typology and determines the maximum transportable load (e.g. a trailer or a semi-trailer can have two or three axles). The typology proposed in the Bilan Carbone® method is reproduced below [ADE 10a, p. 33]. A large amount of detailed technical information about the vehicles is given online on the Logistique Conseil website [LOG 18]. GVWR
average PCmax (kg)
Less than 1.5 t
400
1.5–2.5 t
700
2.6–3.4 t
1,200
3.5 t
1,400
3.6–5 t
2,370
5.1–6 t
2,840
6.1–10.9 t
4,690
11–19 t
9,790
19.1–21 t
11,620
21.1–32.6 t
16,660
Tractor + semi-trailer (40 t)
25,000
GVWR: gross vehicle weight rating. PCmax: payload capacity.
Table 4.1. Categories of lorries and their characteristics depending on the former typology of the Base Carbone®
4.4.1.3.1. VKm method: calculation of emissions from the truck kilometerage DEFINITIONS AND NOTATIONS.– D: total distance traveled by the truck, including journeys made when empty. α: percentage of the total distance traveled when empty. β: percentage of the payload capacity of the loaded truck. EFV: emissions from combustion and previous for diesel per truck and per km, when empty.
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Climatic Impact of Activities
EFC: emissions from combustion and previous for diesel per truck and per km, when loaded. EFF: emissions due to manufacturing of the truck, normalized to 1 km. For a fleet of lorries in use by the organization (owner or not), the vehicle production emissions are counted as emissions associated with fixed assets, and we therefore consider that EFF = 0. Provision of the emissions factors EFv, EFc, EFF in the Base Carbone® leads to the generic calculation formula for EFvkm (see demonstration in Appendix 2): EFvkm = β (1 - α) (EFC - EFV) + EFV + EFF When the percentage of the distance traveled empty (α) and the percentage of the payload capacity when loaded (β) cannot be determined, it is possible to use the following statistical values by default, for France.
Figure 4.3. Schematic method of transportation using the VKm method
IMPORTANT.– Calculation of the emissions is carried out easily by multiplying the emissions factor EFvkm by the distance (D) traveled by the truck for the totality of the circuit. For a given type of merchandise, when there are several deliveries, and all other conditions are equal (type of truck mobilized, journey, percentage of the distance traveled when empty and percentage of the payload capacity when loaded), it is possible to cumulate kilometerage (obviously for a single fictitious truck, no matter how many real trucks are placed in circulation for this transport).
Calculation of Emissions
EFF
EFV
EFC
α
Petrol engines Less than 1.5 t 1.5–2.5 t 2.6–3.5 t Diesel engines Less than 1.5 t 1.5–2.5 t 2.6–3.4 t 3.5 t 3.6–5 t 5.1–6 t 6.1–10.9 t 11–19 t 19.1–21 t 21.1–32.6 t Tractor + semi-trailer
EFvkm
β
(kg CO2e/vehicle.km)
55
(kg CO2e/v.km) Including carbon amortization for the vehicle Yes No
0.033 0.040 0.047
0.238 0.269 0.473
0.238 0.269 0.473
20% 20% 20%
26% 30% 29%
0.271 0.309 0.520
0.238 0.269 0.473
0.025 0.030 0.037 0.039 0.043 0.052 0.059 0.075 0.077 0.086
0.212 0.247 0.318 0.365 0.492 0.386 0.573 0.753 0.869 1.092
0.212 0.247 0.318 0.365 0.709 0.555 0.824 1.084 1.250 1.572
20% 20% 20% 20% 20% 20% 19% 18% 15% 30%
26% 30% 29% 30% 30% 30% 35% 43% 42% 50%
0.237 0.277 0.355 0.404 0.587 0.479 0.703 0.945 1.082 1.346
0.212 0.247 0.318 0.365 0.544 0.427 0.644 0.870 1.005 1.260
0.110
0.911
1.311
21%
57%
1.201
1.091
Table 4.2. Emissions factors expressed in kg of carbon dioxide equivalent per truck and per kilometer (calculations carried out according to the data in the ADEME Base Carbone®, version V6.1 [ADE 10a ], for EFf, EFv, EFc, α, β). For a color version of this table, see www.iste.co.uk/rossignol/climatic.zip
4.4.1.3.2. TKm1 method: calculation of the emissions from the tonnage and kilometerage of the merchandise – Option 1: simple journey We designate by “simple journey” the transportation of merchandise that is carried out by a given type of truck, only for this merchandise, or mixed with others in a known proportion. In other words, PCmax is the transportable payload capacity for a given type of truck. The global emissions factor is expressed by (see the demonstration in Appendix 2): EFtkm = [ (EFC - EFV) + (EFV + EFF) / β (1 - α) ] / PCmax
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Climatic Impact of Activities
When the parameters α and β are not known, we use by default the statistical values for the country under consideration, and the emissions factors are provided in Table 4.3.
Figure 4.4. Schematic method of taking transportation of merchandise into account using the TKm1 method. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
Petrol engines Less than 1.5 t 1.5–2.5 t 2.6–3.5 t Diesel engines Less than 1.5 t 1.5–2.5 t 2.6–3.4 t 3.5 t 3.6–5 t 5.1–6 t 6.1–10.9 t 11–19 t 19.1–21 t 21.1–32.6 t Tractor + semi-trailer
EFvkm EFtkm (kg CO2e/v.km) (kg CO2e/t.km) Including carbon amortization for the vehicle Yes Yes No
α
β
PCmax (t)
20% 20% 20%
26% 30% 29%
0.46 0.70 1.24
0.271 0.309 0.520
2.832 1.839 1.808
2.487 1.601 1.644
20% 20% 20% 20% 20% 20% 19% 18% 15% 30%
26% 30% 29% 30% 30% 30% 35% 43% 42% 50%
0.46 0.70 1.24 1.40 2.37 2.84 4.69 9.79 11.62 16.66
0.237 0.277 0.355 0.404 0.587 0.479 0.703 0.945 1.082 1.346
2.477 1.649 1.234 1.202 1.032 0.702 0.529 0.274 0.261 0.231
2.216 1.470 1.105 1.086 0.957 0.626 0.484 0.252 0.242 0.216
21%
57%
25.00
1.201
0.107
0.097
Table 4.3. Emissions factors expressed in kg of carbon dioxide equivalent per metric ton of merchandise and per kilometer (calculations carried out using the data in the Base Carbone®, version V6.1 of the ADEME [ADE 10a ], for EFf, EFv, EFc, α, β). For a color version of this table, see www.iste.co.uk/rossignol/climatic.zip
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57
IMPORTANT.– The emissions from transport are obtained by multiplying the emissions factor EFtkm by the tonnage (P) and the distance (d) traveled by the merchandise. 4.4.1.3.3. TKm2 method: calculation of the emissions from the tonnage and kilometerage of the merchandise – Option 2: complex journey If a transportation company is used, the situation becomes complicated, because the collection, distribution and transport between depots involve various categories of trucks for mixed merchandise from several clients. DEFINITIONS AND NOTATIONS.– P: tonnage of merchandise (expressed in kg). PP: weight of a full pallet of the merchandise in question (extrapolated if necessary if the pallet is in reality not filled) (expressed in kg). ∆: distance between the county towns of the dispatch and destination departments (French counties).
Figure 4.5. Schematic method of taking transportation of merchandise into account in the TKm2 method. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
The emissions calculation here uses nine equations that are valid in the specific domains defined by the population density of the destination department and by the dispatched tonnage (P) normalized to the weight of the full pallet (PP) (Appendix 2). Selection of the type of destination department is made using the list given in the Appendix, section A2.3.2. These equations have been deduced from an analysis carried out by the author, from the calculation regularities that are observed in the method (version 6.1) designed by Jean-Marc Jancovici for ADEME [ADE 10a].
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Climatic Impact of Activities
SUMMARY.– Calculation of the emissions (E, in kg CO2e) of combined road transport. – A “small wholesaler” (SW) destination department. If P < 4.0 PP
E = (0.01260 + 1.064.10-4 ∆ ) P
If 4.0 PP ≤ P < 23.8 PP
E = (0.00500 + 1.064.10-4 ∆ ) P
If 23.8 PP ≤ P < 33.1 PP
E = (0.00192 + 1.064.10-4 ∆ ) P
– A “medium wholesaler” (MW) destination department. If P < 4.0 PP
E = (0.02077 + 1.064.10-4 ∆ ) P
If 4.0 PP ≤ P < 23.8 PP
E = (0.00825 + 1.064.10-4 ∆ ) P
If 23.8 PP ≤ P < 33.1 PP
E = (0.00408 + 1.064.10-4 ∆ ) P
– A “large wholesaler” (LW) destination department. If P < 4.0 PP
E = (0.03725 + 1.064.10-4 ∆ ) P
If 4.0 PP ≤ P < 23.8 PP
E = (0.01479 + 1.064.10-4 ∆ ) P
If 23.8 PP ≤ P < 33.1 PP
E = (0.00844 + 1.064.10-4 ∆ ) P
In the domain where P ≥ 33.1PP, irregularities prevent the emissions from being expressed in the form of a linear equation as a function of P. As an initial approximation, we can use equations for the domain [23.8; 33.1[, knowing that the emissions will be overestimated. This is entirely acceptable, but if the majority of transport for large quantities is carried out under the conditions P ≥ 33.1PP, then there would be a justification for using the Bilan Carbone® (version 6.1) calculation tools. IMPORTANT.– The emissions from transport are obtained by multiplying the emissions factor EFtkm by the distance (d) traveled by the merchandise. 4.4.1.3.4. Summary of methodology Using the two logic diagrams below (Figures 4.6 and 4.7), you can determine the most appropriate method to use for the calculation of emissions, as a function of the parameters that you have at hand.
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59
Figure 4.6. Determination of the choice of the most appropriate emission calculation method for the transport of merchandise
COMMENT ON FIGURE 4.6.– D is the cumulative kilometerage of the truck (or of the trucks in the same category), empty journeys included, which carries out the rotations under the same conditions (same merchandise, percentage of the distance traveled empty and percentage of the payload capacity in identical loading). Remark: the possibility of calculating the emissions using the VKm method does not prevent the use of the TKm1 method too, which would give the same result.
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Climatic Impact of Activities
Figure 4.7. Determination of the emission calculation formula using the TKm2 method as a function of the population density in the destination department, and as a function of the density and the weight of the merchandise
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61
4.4.2. Non-road transport Non-road transport, that is, railway, fluvial, maritime and air transport, is relatively easy to process on the basis of the tonnage and kilometerage traveled by the merchandise, as a function of the type of train, boat or airplane, and using emissions factors provided by the Base Carbone® [ADE 18b]. 4.5. Emissions due to movements of people Journeys are taken into account for all means of transport: road, railway, air, maritime, etc., whether they are carried out for work or for travel between the home and place of work. Journeys made by visitors to the organization for which the balance is being carried out, are also processed. Visitors are people who go to an organization but are not part of it (clients, sales representatives, visitors in the strict sense of the term, etc.). Take note that delivery personnel and external personnel on missions for the organization are not visitors, and their contribution is counted as part of the items for the transport of merchandise and services respectively. Journeys made by visitors can be evaluated using an occasional questionnaire or by establishing estimation scenarios. Accounting for emissions can be carried out directly from the fuel consumption when it is known, or even on the basis of the kilometerage completed, as a function of the category of vehicle. The Base Carbone® [ADE 18b] provides the following emissions factors: – petrol – premium grade unleaded (95, 95-E10, 98) (combustion + previous): EF = 2.808 kg CO2e/liter – diesel (combustion + previous): EF = 3.158 kg CO2e/liter – kilometric emissions factors depending on the engine specification and tax rating category (combustion, previous and vehicle manufacturing): For other types of fuel (petrol E85, diesel B30, CNG, LPG, etc.), for other means of transport and for other calculation methods, see the documentation and database of emissions factors provided by ADEME [ADE 18a, ADE 18b].
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Climatic Impact of Activities
Engine specification Administrative rating category
Petrol EF (kg CO2e/km)
Diesel EF (kg CO2e/km)
Lower than or equal to 5 HP
0.234
0.229
From 6 to 10 HP
0.272
0.261
Higher than 10 HP
0.337
0.352
Table 4.4. Kilometric emissions factors as a function of engine specification and tax rating category (combustion, previous and vehicle manufacturing)
4.6. Emissions due to waste treatment The waste generated by an activity comes from various flows that are represented schematically in Figure 4.8. Once the type of process (composting, incineration, storage) has been identified and the quantities for each category of waste estimated, the calculation of emissions does not present any difficulties when the Base Carbone® [ADE 18a, ADE 18b] is used as a basis. Take note that the emissions factors regarding waste treatment include the contribution from their transport. The latter should therefore not be taken into account in the emissions due to transport. Waste repurposing as materials or sources of energy allows the quantities of materials produced exclusively from new resources to be reduced (minerals, primary energies) and therefore emissions to be avoided. The energy repurposing and recycling industries are obviously emitters in themselves, but they have less of an impact on the climate, in comparison to a less efficient imaginary situation. If you calculate these avoided emissions, they must not, under any circumstances, be removed from the balance. Take note, however, that this type of calculation can be delicate and it is necessary to rely on methodological elements given in the chapter dedicated to avoided emissions for each type of waste and each method of repurposing proposed by ADEME [ADE 18e].
Calculation of Emissions
63
Figure 4.8. Flows of materials that generate waste. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
Recycling is a closed loop process, because a material can indefinitely follow the cycle of production-use-reincorporation (notwithstanding the inevitable losses that need to be compensated for with the primary raw material). Schematically, the following processes are activated (Figure 4.9): 1) collection and transport; 2) management by processing centers (sorting, handling, storage, etc.); 3) new material re-manufacturing operation. The emissions due to (1) and (2) are counted as waste treatment and those due to (3) are counted under production of inputs (they are generally lower than when starting from the “primary” raw material). The following calculation explains the emissions factor for the new material, incorporating a proportion of recycled material and the emissions that are thus avoided as a function of the climate impact of each of the stages considered independently (production exclusively from a raw material, on the one hand, or from a secondary recycled material, on the other hand).
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Climatic Impact of Activities
Figure 4.9. The new mixed material is obtained by mixing recycled material (in proportion α) and primary material (in proportion 1-α) (the previous phase of recycling, collection, transport, storage and handling is counted as waste). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
NOTATIONS.– EPM: emissions from the production of material exclusively from primary material. EPMR: emissions from the production of mixed material from the mix of primary material and recycled material. M: mass of material produced. Π: emissions factor for the fabrication of material from the primary material. φ: emissions factor for the transformation of the recycled secondary material. α: proportion of recycled material in the mixed material that is made from the mix of raw material and recycled material.
Calculation of Emissions
65
Without the incorporation of recycled material: EPM = m Π With the incorporation of recycled material: EPMR = (1 - α) m Π + α m φ The emissions factor (for 1 metric ton) is therefore: EFPMR = (1 - α) Π + α φ = Π – α (Π - φ) Reduction of emissions through the incorporation of a proportion α of recycled material (as an absolute value): EPM - EPMR = α m (Π - φ) EXERCISE 4.1.– For organic, mineral and plastic waste, the tab “Waste treatment” in the Base Carbone® [ADE 18b] proposes the options of incineration, storage and composting, depending on the materials, but not a recycling option. And yet, a significant part of this waste is effectively recycled. How can this be explained? The following values, taken from the Base Carbone® for end of life, are very unequal depending on the materials: how can these differences be justified? Incineration
Storage
Minerals
EF (kg CO2e/t)
46.6.
33.0
“Average” plastic
2.680
33.0
Paper
46.6
1,020
Card
46.6
983
(Answer in section 4.11) EXERCISE 4.2.– Energy repurposing of oils at their end of life by incineration is planned. Give an estimate of the emissions factor of the processing of (1) used vegetable oils and (2) used synthetic “engine” oils.
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Climatic Impact of Activities
For processing by incineration, the Base Carbone® [ADE 18b] provides, in particular, the following emissions factors: Type of waste Minerals Plastics Card and paper Household waste
EF (kg CO2e/t) 46.6 2,680 46.6 362
(Answer in section 4.11) 4.7. Emissions due to the production of tangible assets In accounting, we deduce the operating charges from revenue, but not the amount of tangible assets that are acquired, because they constitute the assets of the company (they are also known as “fixed assets”). On the other hand, each year, a deduction is made for their loss of value, due to obsolescence, wear and tear, deterioration, etc. This amount deducted from revenues is the amortization in accountancy of a tangible asset. The deduction ceases when the cumulative amortization is equal to the original value of the asset. The logic behind the accounting of emissions related to the manufacturing of fixed assets is the same: inclusion of these emissions is spread out over time (Figure 4.10), because the lifetime of the fixed assets exceeds the time duration of the balance (in general, 1 year).
Figure 4.10. Amortization method for the emissions due to manufacturing of a tangible asset (over 10 years, in this example). For 10 years, each year, 1/10 of the emissions are counted. From the 11th year onwards, the amortization is finished and the asset stops contributing to the balance. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
Calculation of Emissions
67
Logically, the duration of carbon amortization is the lifetime of the asset. However, this is difficult to estimate, which is why in practice we choose an arbitrary duration, more clearly defined and with better consensus: the duration of amortization in accounting (see Appendix 3). Normal standard durations determined by general use are attributed depending on the types of assets. As an indication, the durations of amortizations are generally of this order: – offices: 25 years; – industrial buildings and depots: 20 years; – commercial buildings: 20–50 years; – road networks: 15–30 years; – machines: 6–10 years; – materials: 6–10 years; – automobiles: 5–10 years; – trucks and industrial vehicles: 4–8 years; – furniture: 10–15 years; – IT equipment: 2–5 years; – office equipment: 3–10 years. To calculate the annual contribution (e) of the manufacturing of fixed assets, it is necessary to begin by determining the age of the assets (A) and their duration of amortization (T). If A ≤ T, then the ratio (e) of the manufacturing emissions (E) to be counted in the annual balance is: e = E/T If A > T, then e = 0. The emissions factors of various types of assets are provided by ADEME [ADE 18b], which recommends counting the carbon amortization of goods that are being used, whatever their status, and whether they are possessed or rented [ADE 10c, p. 115]. It must be noted that certain methods avoid the delicate question of amortization of the emissions by imputing to the annual balance the totality of emissions related to the manufacturing of tangible assets acquired in that year. This is an elective option in ISO 14064 and the only method possible with the Greenhouse Gas Protocol.
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Climatic Impact of Activities
Obviously, it is impossible to remedy the emissions related to the fixed assets, because they are observed in the past, during manufacturing of the assets. Why then should we encumber ourselves with calculations that may require fastidious collection of data? Quite simply, to direct future investments more usefully. Becoming aware of the carbon cost of certain tangible assets can encourage other technical choices, when these come up for renewal. 4.8. Emissions due to the use of products Although students are often surprised by this, accounting for emissions due to the use of products by the clients is perfectly legitimate and pertinent, because the manufacturers are generally able to activate leverage to reduce these emissions. This would be the case of a fridge manufacturer that would improve energy efficiency of their appliances or waterproofing of the refrigeration units. For the same service, less electricity and less leakage of refrigerating fluid would reduce the carbon imprint of the use of these materials. Direct emissions that can be applied to the use of products can be related to their conservation, their preparation for use, their use itself (transformation, assimilation, energy required) and maintenance and aging (e.g. clearing out of materials). For a cattle feed producer, we will restrict ourselves to the greenhouse gas emissions related to handling for distribution, digestion and excretion of the animals (depending on the composition of the foods in terms of protein, in particular). In the case of an automobile manufacturer, the main direct emissions related to the use of products are due to the consumption of fuel by the users, which excludes the energy emissions related to the construction and maintenance of roads, although they are just as necessary as the fuel for the use of automobiles. For this type of long-lasting asset and use, it is necessary to count the emissions over the entire lifetime of the assets produced in the year of the balance (we could also count only the annual emissions, but for the entire operational fleet, independent of the year of production (see Figure 4.11)). However, the direct character of the processes related to the use is not necessarily the only pertinent criteria, and it is necessary to question the scope of the emissions to be considered in this group and the reasoning to be implemented in its definition. Let us consider two examples: supply of tray meals to an airline for consumption by passengers and the production of cinder blocks for the construction of houses.
Calculation of Emissions
69
In the first case, what are the emissions related to the use of the tray meal product? Firstly, there is the fuel consumed by airplanes. But from this moment on, the reasoning diverges into two approaches. According to a physical logic, only the emissions from the combustion of the surplus kerosene that is required by the excess weight that the tray meals cause would be counted. The shared use of airplanes by the passengers and by the company that provides the tray meals justifies allocating the emissions from the combustion of kerosene in proportion to the loads. However, viewed in this way, the contribution from tray meals is negligible and does not encourage specific action. We could also recommend the application of the emissions from the total kerosene consumed during the flight due to the use of tray meals. This approach is generally considered to be inexact by novices, with the secondary risk of being counter-productive from an educational point of view. The inconvenience of the maximized calculation is that all effort made to reduce the weight of the tray meals would have no incidence. Effectively, the total quantity of kerosene is not significantly affected by making them lighter. Nevertheless, the idea consists of pointing out that the sale of tray meals is only possible if the airplane takes off, which requires a full tank of kerosene and which truly reveals the dependence of the supplier on fossil energy. This vision is doubtlessly better suited to encouraging the supplier to think about strategic changes, of the order of the diversification of their clientele into sectors that are less dependent on oil. The maximalist approach presents a real problem of outlining the system to be considered: is it necessary to include the energy emissions related to the operation of airport infrastructures, just as necessary for the use of tray meals and just as contributory to the sharp increase in the price of oil? In the second case, concerning building construction, what would the emissions be in relation to the use of the “cinder block” construction material? It goes without saying that it would not be possible for the material to be put in place without mortar, nor if used as housing without external rendering or insulation or wall coating. Is it necessary to add the emissions due to manufacturing and assembly of the heating, plumbing and electricity installations, next to the walls? These installations are not a construction requirement for use of the cinder blocks. However, the type of the heating installation required would be different depending on whether the house is located in Oslo or in Tenerife. If we answer this question in the affirmative, then it would be necessary to consider the entire wall and the roofing that protects the wall from the humidity. However, what action can the cinder block manufacturer put in place to reduce the manufacturing and assembly emissions of the roofing? Probably none. Moreover, the energy expenditure depends on the quality of the insulation, which is itself a consequence of the more or less insulating nature of the wall construction material. It would be legitimate to count, for the indirect emissions related to the use of cinder blocks, the emissions from energy consumption over the course of the entire lifetime of the building. We could respond that the energy losses depend on the insulating material/load-bearing
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Climatic Impact of Activities
material pairing. In this case, is it up to the insulation that fulfills this function, to assume all these heating emissions or is it legitimate for us to proceed to allocate the emissions related to heating to both the insulation material and the cinder block, in inverse proportion to their thermal resistance? In brief, the definition of the scope of emissions related to the use of products is not immediate. We could reasonably select the associated emitting processes which respond to one or the other of the two following conditions. CRITERIA FOR CONSIDERATION OF THE ASSOCIATED PROCESSES.– 1) If improvement of the product leads to a reduction in the emissions related to associated processes (e.g. improvement of the thermal resistance of a material which reduces the emissions from the production of insulation and heating). 2) If the associated processes for implementation and use of the product are strictly necessary (e.g. the emissions from the production of the essential grouting mortar in the case of a construction material).
Condition (1) is eminently pertinent and a priority, because it indicates change levers. It can lead us to allocate emissions in the case of collective or shared use (case of tray meals, for example, where the kerosene consumed would only be counted in proportion to its weight, relative to the weight of passengers and luggage). We can legitimately question the pertinence of condition (2) if condition (1) were not fulfilled. Indeed, what benefit would there be in forcing ourselves to quantify the emissions of a process associated with the use of a product which is strictly necessary, but for which the product manufacturer would not a priori have any means of reducing the carbon impact? Nevertheless, the preconceived ideas about consideration of potential change levers are not necessarily reliable and we can decide to count emissions from all processes that are directly concerned by the implementation or the use of the product to, in fact, provoke thoughts and question preconceived ideas about the non-effectiveness of the actions to reduce emissions. In the case of the cinder block, this type of reasoning leads to taking into account the processes indicated in Table 4.5. In conclusion, we insist that the choice of options is not standardized, that it remains free, but on the condition that sound arguments are presented and transparency of reasoning is guaranteed, knowing that the priority is not with the accounting, but with the reduction of emissions somewhere, which can lead to strategic questioning of the economic vulnerability related to the dependence on fossil energy and on its enrichment.
Calculation of Emissions
Processes associated with the use of the product Energy for handling Grouting mortar External rendering Insulation layer Wall coating Protective roofing Installations fixed to the walls (electricity, heating, plumbing) Operational energy expenditure
Condition (1) ?
71
Condition (2)
Table 4.5. Processes taken into account for the emissions due to the use of a construction material (cinder blocks)
The notion of a product often needs to be interpreted. In the case of manufacturing companies, it obviously corresponds to the usual meaning of artifact. For other types of activities, intellectual activities, services, etc., it is necessary to think about what “product” should actually mean, insofar as in the logic of the broad spectrum balance, this notion could be extended to a reality that is far removed from the organization at hand, both in terms of the nature of what it is and the scale taken into account. Let us look at the case of an industrial chemistry research laboratory. The activity produces knowledge. When it becomes necessary to put this observation into concrete terms, it quite quickly appears that the knowledge is only reality if it is communicated and implemented. The researchers thus publish articles in national and international specialized scientific journals. The emissions related to the use of the product are here those of the editorial activity, which needs to be estimated, in relation to the published content and with the same type of arbitration over allocation (in the proportion of the number of pages of the article compared to the number of pages in the journal, or not). Communication of research results also occurs via the participation of researchers in symposiums, for which the emissions related to journeys, accommodation, etc. must be estimated. However, in the particular case of an industrial chemistry research laboratory, the product is also the design of procedures that will be applied on an industrial scale. Naturally, it is necessary to quantify the emissions generated by the chemical production installations, under “use of the product”. In addition, it is probable that the emissions from the laboratory are miniscule compared to those in the industrial production units that are a consequence of this research. We can take into account the emissions from the manufacturing procedures used in various ways: – annual emissions from all industrial installations designed and in operation; – emissions from the units in service in the year of the balance over the duration of their lifetime.
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Climatic Impact of Activities
In this second approach, since the research extends over several years, it is possible to spread the emissions over the duration of the studies. However, the physical justification hardly has any benefit from the perspective of a climate footprint reduction policy for the laboratory. Relating methods of this kind used in accounting for emissions to the use of the “product” acceptable to a small research unit requires much educational talent, given the disproportionate quantities between the more or less direct emissions of the laboratory and those of the client industry. However, this vision of the climate footprint is perfectly legitimate and pertinent, because it attributes responsibility to technoscience in the momentum of a decarbonated economy. Innovation for itself or innovation steered by the priority given to making a profit are no longer sufficient motivations for our society to engage in an economic trajectory that is compatible with the perennial coexistence of other forms of life. 4.9. Emissions due to the end of life of products The same configuration arises as for the use of products, that is, taking into account the existing stock or the annual production over the course of its lifetime (see Figure 4.11).
Figure 4.11. Schematic diagram of two accounting reasonings for emissions related to the use and end of life of products. The diagram is incomplete, because it would be necessary to go back to all production in the previous years for which there would still be products in service in the year of the balance (year n)
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73
This group requires hypotheses to be made concerning the end of life of the products and calculations to be carried out of the emissions generated by the processing activities recommended for the emissions related to waste (section 4.6). COMMENT ON FIGURE 4.11.– – Case 1: emissions of products manufactured in the reference year taken into account, over their entire expected lifetime (surface σ ): (Pn + ∑Fi ) for i > n (Fi tends to zero in the future, with progressive obsolescence of products); it is necessary to model the evolution of the stock manufactured in year n). – Case 2: emissions from the existing fleet in the year of the balance taken into account (cumulation of the products previously manufactured and still in service in the year of the balance: (Pn + ∑Fi ) for i ≤ n-1 (Fi tends to zero, with the increase of the age of the products); it is necessary to model all the fleet in existence in year n). 4.10. Calculation of uncertainties Calculation of the carbon footprint of an organization is approximate. Indeed, exceptions aside, like an electricity consumption reading on a bill, the data is rarely correct. The calculation is based on hypotheses, estimated scenarios (e.g. movement of visitors), investigations that are never exhaustive nor totally reliable, unverifiable hearsay, etc. The emissions factors themselves are combined with their own uncertainty. An approximate result does not prevent us from reasoning or acting judiciously! On the other hand, it is useful to know the uncertainty (or the confidence interval) of each intermediate calculation. The uncertainties for emissions factors are provided by ADEME [ADE 18b]. For activity data, it is necessary to determine them. It is rare for this to be the entire subject of a numerical calculation and it is generally necessary to make estimates of them. By way of example1: – 0–5% for data from a direct measurement (bills or counters); – 15% for reliable unmeasured data; – 30% for recalculated data (extrapolation); – 50% for approximate data (statistical data); – 80% for data known in an order of magnitude.
1 The author contributed, via the Institut de formation carbone, to the definition of these uncertainty ranges, for the update to the Bilan Carbone® documentation, version 8.
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Climatic Impact of Activities
The uncertainty is absolute when it represents a quantity expressed in the same unit as the dimension that it affects (metric ton, kg CO2, etc.). It is relative if we express it in a percentage of the calculated value. An uncertainty of 20% for a result of 150 t CO2e, noted 150 ± 20% t CO2e, means, in absolute value, that the probable value is found in the range [150-30; 150+30] t CO2e, noted 150 ± 30 t CO2e. How is the uncertainty calculated for a result that involves a variety of operations, given the uncertainty on the parameters? According to the IPCC, International Panel on Climate Change, the uncertainty is half of the confidence interval of 95% divided by the total and expressed as a percentage. It can be calculated as follows [GIE 18, p. 13]. For an emission calculated by multiplying the quantity of flow (activity data) by the corresponding emissions factor: E = Q . EF with the following uncertainties on the parameters: ∆Q/Q = q % ∆EF/EF = ef % The resulting uncertainty is given by the equation: ∆E/E = (q2 + ef2)1/2
[4.1]
For the sum of two emission values: ε = E1 + E2 with uncertainty on Ei : ∆Ei/Ei = ei %. The uncertainty on the sum is given by: ∆ε/ε = [ (E1 e1)2 + (E2 e2)2 ]1/2 / (E1 + E2) The calculation expressions are generally more complicated, and these rules need to be adapted to sums and/or multiplications that include more than two terms. The following observations will then be useful.
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75
If we note “x” as a parameter, its relative uncertainty is noted “x*”. – The uncertainty on a product of several xi terms follows the structure of the formula [4.1] with as many squares xi2 as there are terms to multiply: A = ∏ xi A* = ( ∑(xi*2) )1/2 – Multiplication of a parameter with no uncertainty by an uncertain value does not modify the value of its relative uncertainty: P=λx if λ* = 0 then: P* = x* Effectively: P* = ((λ*2) + (x*2))1/2 = x* – The uncertainty of a sum of more than two terms is given by: S = ∑ xi S* = [ ∑(xi xi*)2 ]1/2 / ( ∑ xi )
[4.2]
What happens if we calculate a sum of more than two terms in several stages, by carrying out intermediate calculations of uncertainties on partial sums, then by calculation of the uncertainty for the sum of the aggregated parts? The generic formula [4.2] remains valid, on the condition that the x and x* resulting from the intermediate sums are correctly interpreted. So, S = a + b + c + d. We can calculate the intermediate sums: X = a + b and Y = c + d: X* = [ (a a*)2 + (b b*)2 ]1/2 / (a + b) Y* = [ (c c*)2 + (d d*)2 ]1/2 / (c + d) Then, the overall sum: S = X + Y: S* = [(XX*)2 + (YY*)2 ]1/2 / (X + Y)
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Climatic Impact of Activities
It would be demonstrated that the uncertainty would have been the same if we had proceeded without intermediate aggregation: S* = [ (a a*)2 + (b b*)2 + (c c*)2 + (d d*)2 ]1/2 / ( a + b + c + d) The uncertainty on the sum of more than two terms is equal to the uncertainty of the sum of sub-totals (each sub-total is associated with an uncertainty that is itself calculated according to the formula [4.2]). TAKE NOTE.– The addition of an uncertainty parameter that is zero to an uncertain value is not neutral! A=x+y A* = [(x x*)2 + (y y*)2 ]1/2 / (x + y) If y* = 0 A* = x x* / (x + y) A* ≠ x* “Manual” calculation of uncertainties is laborious, but necessary. Nevertheless, to avoid making a fastidious presentation of the case studies, the calculation of uncertainties will not be exhaustively explained. We will limit ourselves here to presenting two examples that relate to the greenhouse gas emission balance of the brickworks seen in case study no. 1, for items E5.2a and E7.3. 4.10.1. Emissions due to the incineration of plastic waste (see section 6.1.3.7.3) E7.3 = Q . EFincineration
written Q . EFin
(EFin is the emissions factor for the incineration.) The quantity of plastic waste, Q (1 metric ton), has been evaluated to the nearest 30%: Q = 1 ± 0.3 t
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77
According to the Base Carbone® [ADE 18b]: EFin = 2,680 ± 50% kg CO2e/t, that is, 2.68 ± 50% t CO2e/t E7.3 = 1 x 2.68 = 2.68 t CO2e rounded to 2.7 t CO2e E7.3* = ( Q*2 + EFin*2 )1/2 E7.3* = ( 0.32+ 0.52 )1/2 = 0.58, that is, 58% E7.3 = 2.7 ± 1.6 t CO2e 4.10.2. Emissions due to transportation of sawdust supplies (see section 6.1.3.5.2) E5.2a = Ds . EFvkm = Ds [ β (1- α) (EFC - EFV) + EFV + EFF ] Refer to section 6.1.3.5 for the numerical values of the parameters in this expression: E5.2a = 134,400 [ 1 (1 – 0.5)(1.311 – 0.911) + 0.911 + 0 ] / 1,000 = 150 t CO2e To simplify the way this is written, we re-name the values: E5.2a = a [ b (1 - c) (d - e) + ( f + g ) ] E5.2a = a K with K = A + B; A = b (1 - c) (d - e); B = f + g. A* = [ b*2 + (1 - c)*2 + (d - e)*2]1/2 (1 - c)* = [0 + (cc*)2]1/2 / (1 - c) = cc*/(1 - c) (d - e)* = [(d d*)2 + (e e*) 2]1/2 / ( d - e ) B* = [(f f*)2 + (g g*)2]1/2 / (f + g) K* = [ (A A*)2 + (B B*)2]1/2 / ( A + B ) E5.2a* = [a*2 + K*2]1/2
[4.3]
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Climatic Impact of Activities
The relative uncertainty over the distance traveled D is: a* = 0.1% When loaded, the percentage of payload capacity (β) is 100%, and the percentage of journeys made empty (α) is 50%. These figures are known with certainty: β = 1.00 ± 0
b* = 0
α = 0.50 ± 0
c* = 0
The relative uncertainty presumed for each of the other parameters is 15%: d* = e* = f* = 0.15 (g and g* are zero; see justification on section 6.1.3.5) Calculation of the expression [4.3] with these values returns the uncertainty related to the emissions for wood sawdust transport: E5.2a* = 60% E5.2a = 150 ± 90 t CO2e In conclusion, it is necessary to draw attention to the benefits of calculating the uncertainties. The data in the Base Carbone® are always associated with an uncertainty, and the Bilan Carbone® method carries out a systematic calculation of this. This transparency is totally exceptional and exemplary in the range of databases and calculation tools that are available. Display of uncertainties is essential for interpretation of the figures and correct reasoning. For example, we could spontaneously prioritize the actions to be put in place to target a significant emission group, to the detriment of a relatively modest group. Nevertheless, great uncertainty surrounding the latter makes it potentially much higher, or comparable to the first, which would require an attempt to refine the calculation to reduce the uncertainty and/or not to neglect, by precaution, the actions to be taken into account for this item too. I have sometimes been able to observe the disappointment of certain students who realize that the order of magnitude of the uncertainties in greenhouse gas emission balances could be high, to the extent that, in their eyes, they taint the credibility of the emission quantification method! This is an inversion of judgement, which reveals a significant epistemological deficiency concerning what the figures
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79
represent in science. Any calculation involving measurements and data from reality is necessarily tainted with an uncertainty, conferred by the uncertainties concerning data. Unfortunately, generally the required uncertainty calculations are not imposed, to the extent that the usual manipulation of the figures “alone” leads us to believe that these are exact values, to the point of casting suspicion on the rigorous and transparent calculations about uncertainties, in comparison. 4.11. Answers to the exercises in Chapter 4 Answer to exercise 4.1 (section 4.6) Recycling, in broad terms, involves several successive processes: collection, transport, handling, sorting, storage, in preparation for various processes to re-manufacture new material. The phases of the cycle that are taken into account under the category of waste are those that precede the transformation of the recycled material, which is itself taken into account in the production of future inputs. The end-of-life emissions factors given by the Base Carbone® are for the following materials: EF (kg CO2e/t)
Incineration
Storage
Minerals
46.6
33.0
“Average” plastic
2,680
33.0
Paper
46.6
1,020
Card
46.6
983
The high emissions factors illustrate emitting processes that add to a common basis of emissions that are independent of the materials, of the order of 30–50 kg CO2e/t, mainly related to the fossil energy that is required for transport and handling operations and to the operation of incineration plants. The much higher emissions factor for incinerated plastics expresses the destockage of carbon due to combustion of materials from the petrochemical industry (CO2 of fossil origin). The emissions factor for the storage of paper and card is justified by anaerobic fermentations with emanation of methane that is not totally captured.
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Answer to exercise 4.2 (section 4.6) Vegetable oil is a biogenic carbonated material whose combustion produces carbon dioxide which belongs to the short cycle, with no additional greenhouse effect. From the point of view of combustion, this type of oil is similar to paper, made of vegetable fibers. The emissions factor of processing in an incineration plant can be estimated, as an order of magnitude, to be 50 kg CO2e/t. The synthetic mechanical oil is from the petrochemical industry and its combustion gives off carbon dioxide of fossil origin, in the same way as plastic materials whose emissions factor for incineration can be used as a reference, in other words, of the order of magnitude: 2,700 kg CO2e/t.
5 Results Analysis
5.1. Recommended actions The main goal of the preceding methodological stages lies in the following: creating actions to reduce direct or indirect emissions of greenhouse gases, supported by the emission profile produced by the investigation and calculation. The possible actions are highly diverse and depend on the activity; some examples will be presented with the case studies that are examined in Chapter 6 of this book. The recommendations need to be accompanied by an initial technical and economical feasibility study and a calculation of the expected reductions in emissions made by implementing the actions. In the process of looking for solutions, it is highly recommended to involve managers and competent persons, in order to guarantee the pertinence of the proposals, as well as the people who will have to instigate the changes, to make sure that the actions are effective and long-lasting. 5.2. Interpreting balances Comparison of greenhouse gas emission balances from different entities is not advisable in the interest of avoiding false conclusions, even though the activity sector and the size of the organizations are the same. The example illustrated in Figure 5.1 proves this point. It shows balances from seven vineyards in the same wine-growing region, which produce wine of a similar caliber, carried out by the same expert over the same period of time, with the same scope of emissions and the same hypotheses. To avoid bias from the differences in size of the companies,
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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the emissions are normalized to a hectoliter of wine produced. We notice that, for a given emission entry, the orders of magnitude can be very different and that the hierarchy fluctuates between the various emission groups. For example, vineyards that are extremely popular with foreign visitors have emissions linked to the movement of people, which can be disproportionate.
Figure 5.1. Comparative juxtaposition of the emission profiles for seven vineyards of the same caliber and from the same wine-growing region in France. The emissions are comparable because they are normalized to a hectoliter of wine produced (each color represents a vineyard. They are classed in the increasing order of emissions for the energy group). For a color version of this figure, see www.iste.co.uk/ rossignol/climatic.zip
The example above demonstrates that it can be useful to calculate emission ratios, normalized to a unit of turnover, quantity of products, workforce, etc. Be careful, however, because they can lead to a skewed perception. Thus, an evaluation of the reduction of the climate footprint based solely on a ratio must be avoided. It is sufficient for the emissions to increase less than the dimension to which they are normalized in order for a ratio to diminish, although the carbon footprint increases (third case in Table 5.1). A ratio can mask reality.
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For manufacturing companies, a specific ratio is the emissions from activity (without downstream processes: delivery transport, product use and end of life), normalized to the quantity of manufactured products. It then constitutes the emissions factor for the product, but on the condition that it is the only product being manufactured. If more than one product is being manufactured, it is necessary to proceed to allocate the emissions to each of the products. The process is delicate, because different reasonings can take precedence over the attribution of emissions. Will we attach the allocation to the market value, the quantity, the technical or human means implemented for each of them? Everything is possible, and bias is indeed probable. For this type of exercise, it is recommended to take inspiration from the standards that apply to analysis of the life cycle (ISO 14040) and to rigorously and transparently detail the reasons set out for the calculation.
Table 5.1. Three configurations of the evolution of emissions (E) normalized to the quantity produced (P). The ratio of the third case diminishes, although the emissions have increased. For a color version of this table, see www.iste.co.uk/rossignol/climatic.zip
5.3. Carbon dashboard A greenhouse gas emission balance is only useful if it leads to vigilance and a desire to make improvements in the future. It would be illusory to envisage establishing an exhaustive balance each year, due to the time required. However, it is useful, even essential, to have a “carbon thermometer” to steer the strategy and policy of an organization. On the basis of an initial balance, it is possible to construct a simplified tool that restitutes the approximate carbon footprint, by recognizing large emission groups, and those to which reduction actions are applied, as important.
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EXERCISE 5.1.– An initial greenhouse gas emission balance has been established for a reference year. The balance is updated every 3 years. After 6 months, the emissions factor for steel from 40% recycled material goes from 2,354 kg CO2e/t to 2,250 kg CO2e/t. – The first possible reason for this change: the calculation method has improved and the emissions factor has been specified. – Second possible reason: the percentage of recycled steel increases from 40% to 45%. In each of these cases, is it necessary or not to recalculate the emissions for the reference year to provide correct monitoring of the evolution of the carbon footprint? (Answer below) 5.4. Answer to the exercise in Chapter 5 Answer to exercise 5.1 First case: the calculation method has improved, and the emissions factor has been specified. If the emissions factor had immediately been calculated in detail, the new value would have also applied to the reference year. The system itself has not changed, but the calculation method has. It is therefore necessary to recalculate the reference year with the new emissions factor. Second case: the percentage of recycled material has increased from 40% to 45%. If the reference year is recalculated with the new emissions factor, the improvement brought about in the manufacturing process is hidden. This would be a mistake.
6 Case Studies
WARNINGS.– – The emissions factors are from the Base Carbone® provided by ADEME (French Agency for the Environment and Energy Management) [ADE 18b], unless specific information to the contrary is given. The emissions factors in the Base Carbone® that are used in the case studies are valid for France or Europe. If necessary, the reader will need to adapt them to the relevant country. – The emissions factors in the Base Carbone® include fewer decimals than those included in the Bilan Carbone® calculation tool, which could explain the small differences between the results that a reader using this tool would note (depending on the version used, the differences could be greater, given the evolution of the emissions factors). – Some calculations give results with orders of magnitude that are not significant. They are still presented for educational purposes to explain the reasoning that needs to be laid out. – Calculation of the uncertainties is not presented to avoid complicating the explanations and overloading the presentation. Only two examples concerning case study 1 are examined in section 4.10. – Taking account of the relatively large uncertainties that usually affect the type of calculation used in the quantification of emissions, the results must not be presented with too many significant figures. Nevertheless, in the following, for intermediate results, all figures have been maintained in place up to the degree of a unit to make it easier for the reader to check and correct their values. For the final emission values for each group, they are provided in brackets for indication purposes, to the degree of a unit, and are presented as follows: E = 71,000 ± 4% t CO2e (70,224).
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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– Very careful reading of the questions and the lists of data that follow is necessary. Some details that appear to be anecdotal on first reading will turn out to be deciding factors for the reasoning or the calculation. – The cases presented are fictitious but realistic (note: as has been demonstrated in section 5.2, it would be a mistake, and in vain, to try to extrapolate them to real cases). 6.1. Case study 1: brickworks 6.1.1. Description of the activity and challenge in the exercise In south-west France, an expanding business park contains: – a brickworks (subject of study); – an animal feed production factory; – a used tire collection company; – a wood furniture manufacturing factory; – an innovative company whose activity consists of trapping carbon dioxide from large sources of emissions to synthesize sodium bicarbonate. The brickworks make use of two quarries to manufacture bricks in accordance with the general process described in Figure 6.1. Brick has a high thermal resistance (BBC (low energy consumption) standard complied without addition of an insulating material). Specific details for manufacturing need to be noted: – the earth materials extracted from the quarries are marls (85% clay and 15% calcium carbonate, CaCO3); – dried sawdust is incorporated into the paste. When the bricks are fired, combustion of the sawdust particles generates porosity, which increases the insulation capacity and reduces the fragility of the material. This sawdust is a by-product of the wood industry, which is procured from regenerated forests in the region. Examination of the system was conducted to model: 1) the activities that are part of the brick production process, which are both internal and external to the brickworks; 2) the flows of matter and energy, in addition to the related greenhouse gas emissions.
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Then, it will be a case of calculating the emission values, for each group and subgroup, using the method described in Chapter 4. Finally, it will be necessary to imagine solutions that could be recommended for the brickworks, in order to significantly reduce its climate footprint.
Figure 6.1. Fired brick manufacturing process. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
6.1.2. Activity data and emissions factors General data Annual production sold
250,000 t/yr
Workforce
72 people
Quantity of earth required for production of 100 kg of bricks
105 kg
Proportion of calcium carbonate in the earth
15%
Breakage rate of bricks during manufacturing
1%
Weight of a brick
18 kg/brick
Volumetric mass of a brick
808 kg/m3
Weight of bricks on a pallet
1,260 kg/pallet
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Climatic Impact of Activities
Number of bricks required for construction of 1 m2 of wall
16.5 bricks/m2
Atomic mass of calcium
40 g/mole
Atomic mass of carbon
12 g/mole
Atomic mass of oxygen
16 g/mole
In the following, “EF” denotes the emissions factors given online by ADEME [ADE 18b], in January 2018. Emissions related to the use of energy (with the exception of road vehicles) Heavy fuel oil required for drying and firing the bricks
19,100 t/yr
- lower calorific value
40.5 MJ/kg
- EF (combustion and previous)
3,640 kg CO2e/t
Diesel for extraction and handling machinery - EF (combustion and previous) Quantity of electricity consumed
10,000 l/yr 3.17 kg CO2e/l 10,324 MWh/yr
- EF (except transport) (2016)
0.0594 kg CO2e/kWh
- transport: loss in network due to Joule effect
8.9% of electricity consumed
Direct emissions not related to energy No data provided. Emissions due to the production of inputs Manufacturing inputs Earth Sawdust (locally sourced) incorporated into the paste
40,000 t/yr
EF wood with short lifetime or timber
36.7 kg CO2e/t
Engine oil for machinery
500 l/yr
- volumetric mass Mechanical parts for machinery and machines - EF manufacturing Administrative inputs (tools, supplies)
0.840 t/m3 1.75 t 5,500 kg CO2e/t Negligible
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Inputs for brick packaging Wooden pallets
18 kg/pallet
- EF (manufacturing | end of life)
38 | 33 kg CO2e/t
Steel (40% recycled) for binding the pallets
1,100 kg/pallet
- EF manufacturing of new steel
3,190 kg CO2e/t
- EF manufacturing of recycled steel
1,100 kg CO2e/t
- EF end of life
33 kg CO2e/t
Plastic cover in new low-density polyethylene (recyclable) - EF (manufacturing | end of life)
0.800 kg/pallet 2,090 | 880 kg CO2e/t
Emissions due to the transport of merchandise Transport of the sawdust supply, in addition to internal transport of earth to the brickworks and part of the waste from the bricks that is reused as infill in quarries, is carried out by a fleet of rented trucks (semi-trailers for the sawdust and container trucks for the earth and the brick waste). The charges for fuel and drivers are included in the rental. Supply of combustible material and fuel, in addition to the delivery of bricks to clients, are carried out by transporters. The tractor and semi-trailer group is characterized by a gross vehicle weight rating (GVWR) of 40 metric tons and by a payload capacity (PCmax) of 25 metric tons. For the other trucks, these data will be specified case by case. Supply transport Earth Maximum earth load transported per container truck
17 t
Distance between the quarries and the brickworks
18 km
For certain rotations, return to quarries with load of broken bricks (see data below concerning the waste to find out the quantities). Sawdust Type of truck
Tractor + semi-trailer
Tonnage
40,000 t/yr
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Climatic Impact of Activities
Distance from sawdust loading point
42 km (return journey empty)
Heavy fuel oil Type of truck
Tractor + tanker (38,000 liters)
Distance supplier–brickworks
40 km (return journey empty)
Volumetric mass of heavy fuel oil
1,000 kg/m3
Diesel Type of truck
Tanker container (12,000 liters)
GVWR
17.5 t
PCmax
11 t
Distance supplier–brickworks
40 km (return journey empty)
Volumetric mass of diesel
850 kg/m3
Transport of brick delivery Departmental transport Tonnage
20,500 t/yr
Type of truck
Tractor + semi-trailer
Average distance to delivery points
50 km
Transport to neighboring departments Tonnage
80,250 t/yr
Type of truck
Tractor + semi-trailer
Average distance to delivery points
100 km
Regional transport (except for neighboring departments) Tonnage
102,700 t/yr
Type of truck
Tractor + semi-trailer
Average distance to delivery points
180 km
National transport (except for regional) Tonnage
46,550 t/yr
Type of truck
Tractor + semi-trailer
Average distance to delivery points
500 km
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Emissions due to movement of people Journeys residence–work The results of the enquiry are given above. All employees with a company car have responded. Emissions factors for vehicles [ADE 18b]. Petrol ]0-5] CV Combustion | previous | manufacturing 0.157 | 0.037 | 0.040 kg CO2e/km [6-10] CV Combustion | previous | manufacturing 0.188 | 0.044 | 0.040 kg CO2e/km Diesel ]0-5] CV Combustion | previous | manufacturing 0.151 | 0.039 | 0.040 kg CO2e/km [6-10] CV Combustion | previous | manufacturing 0.175 | 0.046 | 0.040 kg CO2e/km
Investigation into journeys made by people between their residence and the brickworks Of the 72 employees, 49 people answered the inquiry. “CC” means “company car”. Ref. Distance Out-return/day
Average
Fuel
001
Vehicle
Diesel
4
2
Tax rating (HP) 5
002
11
1
Vehicle
Diesel
6
003
23
1
Vehicle
Petrol
5
004
3
2
Bicycle
005
7
2
Vehicle
Diesel
5
006
9
2
Vehicle
Diesel
4
007
13
1
Vehicle
Petrol
9
008
3
2
Vehicle
Diesel
7
009
10
2
CC
Diesel
7
010
8
2
Vehicle
Petrol
5
011
15
1
Vehicle
Petrol
5
012
4
2
Bicycle
013
17
1
Vehicle
Petrol
4
014
21
1
Vehicle
Petrol
10
015
5
2
Vehicle
Diesel
7
016
3
2
Vehicle
Petrol
5
92
Climatic Impact of Activities
017
8
2
CC
Diesel
5
018
14
2
Vehicle
Petrol
9
019
11
1
Vehicle
Petrol
4
020
7
2
Vehicle
Petrol
5
021
17
1
Vehicle
Diesel
5
022
1
2
Pedestrian
023
8
2
Vehicle
Petrol
3
024
5
2
Vehicle
Diesel
5
025
16
1
Vehicle
Petrol
7
026
4
2
Vehicle
Diesel
5
027
9
2
Vehicle
Diesel
9
028
15
1
Vehicle
Petrol
8
029
6
2
Vehicle
Diesel
5
030
4
2
Vehicle
Petrol
4
031
19
2
CC
Diesel
5
032
10
1
Vehicle
Petrol
4
033
16
1
Vehicle
Diesel
4
034
8
2
Vehicle
Diesel
6
035
27
2
CC
Diesel
5
036
12
2
Vehicle
Petrol
5
037
18
1
Vehicle
Petrol
4
038
13
1
Vehicle
Diesel
5
039
23
1
Vehicle
Diesel
7
040
3
2
Bicycle
041
4
2
Vehicle
Diesel
10
042
8
2
Vehicle
Petrol
7
043
15
1
Vehicle
Petrol
5
044
14
2
CC
Diesel
5
045
4
2
Vehicle
Diesel
4
046
9
2
Vehicle
Petrol
6
047
19
1
Vehicle
Diesel
5
048
13
2
Vehicle
Petrol
9
049
12
1
Vehicle
Petrol
5
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Journeys made for work Journeys by road Number of company cars
5
Type of engine
Diesel engine
Consumption of diesel by company cars (including residence-brickworks)
10,124 liters
EF (combustion | previous)
2.51 | 0.657 kg CO2e/km
Journeys by air 1) Number of journeys by air Paris–New-York
3
type of airplane
180–250 seats (5,000–6,000 km)
EF (combustion+previous+stratospheric H2O)
0.230 kg CO2e/passenger.km
2) Number of journeys by air in France
9
average distance for a journey
500 km
type of airplane
50–100 seats (≤ 1,000 km)
EF (combustion+previous+stratospheric H2O)
0.453 kg CO2e/passenger.km
Journeys by train Number of journeys by train
23
Average distance of a journey
500 km
Type of train
high-speed
EF (electricity+previous)
3.69.10-3 kg CO2e/passenger.km
Emissions due to transport and treatment of direct waste Waste from production of bricks Proportion of brick waste used as infill in quarries
35%
Proportion of brick waste sent to landfill
65%
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Climatic Impact of Activities
EF inert landfill material
33 kg CO2e/t
Used mechanical oils Incinerated in cement works for energy repurposing
500 l/yr
Volumetric mass
0.840 t/m3
Packaging plastics Annual tonnage
1t
EF (incineration)
2,680 kg CO2e/t
Packaging boxes Annual tonnage
2t
EF (recycling)
983 kg CO2e/t
Emissions related to the manufacturing of fixed assets Fixed asset
Age (year)
Quantity
Emissions factor
500 m2 (floor)
650 kg CO2e/m2 (floor)
15
10,000 m2
275 kg CO2e/m2
20
10,000 m2
73 kg CO2e/m2
15
1,000 t
5,500 kg CO2e/t
Automobiles
3
6t
5,500 kg CO2e/t
Rented trucks
7
200 t
5,500 kg CO2e/t
Old office furniture
15
10 t
1,830 kg CO2e/t
Recent office furniture
3
5t
1,830 kg CO2e/t
Buildings Offices Industrial buildings (metal structure)
32
Roads Car parks and typical roads, tarmac Machines Machines, industrial equipment Vehicles
Furniture
Case Studies
Office equipment CRT screen computers
5
7
678 kg CO2e/unit
Flat screen computers
2
15
1,280 kg CO2e/unit
Printers
2
5
110 kg CO2e/unit
Photocopiers
2
1
2,940 kg CO2e/unit
Emissions due to the use of products Cement required for bricklaying Quantity
5 kg/m2
Composition of cement
cement 39%; sand 44%; water 17%
EF cement
866 kg CO2e/t
EF sand
2.32 kg CO2e/t
EF water
0.132 kg CO2e/m3
External wall rendering EF
4.96 kg CO2e/m2
Application
24 kg/m2 [SNM 15]
[SNM 15]
Materials for doubled layer (Plaster panels 13 mm, including plastering and joints tape) EF
2 kg CO2e/m2 [SGO 15]
Grouting
2.5 kg/m2
Materials for the roofing EF frame made of resinous wood
1.1 kg CO2e/m2 [CRÉ 14]
EF fired clay tiles
14.3 kg CO2e/m2 [NOE 14]
Emissions due to product end of life No data provided.
95
Figure 6.2. Representation of the system associated with the brickworks activity: main processes and flows. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
96 Climatic Impact of Activities
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6.1.3. Calculation of emissions In a generic manner, “Q” designates a quantity of flow and “EF” designates the corresponding emissions factor. 6.1.3.1. Emissions due to the use of energy 6.1.3.1.1. Combustible materials Emissions due to the use of heavy fuel oil for drying and firing bricks: E1.1 = Q . EF E1.1 = 19,100 × 3,640 / 1,000 E1.1 = 69,524 t CO2e 6.1.3.1.2. Fuels Emissions due to the use of diesel for extraction and handling machinery: E1.2 = Q . EF E1.2 = 10,000 × 3.17 / 1,000 E1.2 = 32 t CO2e 6.1.3.1.3. Electricity The line losses due to the Joule effect correspond to a surplus of electricity to be produced. It is therefore necessary to calculate the emissions for a quantity of electricity increased by 8.9% (the Base Carbone® provided by ADEME by default gives the emissions factor, including losses; here, it has been split up for educational reasons): E1.3 = Q (1 + 0.089) EF E1.3 = (10,324.103) × 1.089 × 0.0594 / 1,000 E1.3 = 668 t CO2e Sub-total of energies: E1 = 71,000 ± 4% t CO2e (70,224).
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Climatic Impact of Activities
6.1.3.2. Direct emissions not related to energy (process emissions) 6.1.3.2.1. Decarbonation of the earth materials The earth materials extracted from the quarries are marls (85% clay and 15% calcium carbonate CaCO3). Since the bricks are fired at 1,000°C (indication given by the manufacturing process diagram), the calcium carbonate is reduced to lime and carbon dioxide is produced, which generates an additional greenhouse effect: CaCO3 —> CaO + CO2 (897°C, 1 atm) The production sold is 250,000 metric tons (t), but the manufacturing loss is 1%. To sell 250,000 t, it is therefore necessary to produce a greater quantity X: X – 0.01X = 250,000 X = 250,000 / 0.99 = 252,525 t The brick waste represents the difference; in other words, 2,525 t. 105 kg of earth is required to obtain 100 kg of bricks. Necessary quantity of earth: Tt = 252,525 × 105/100 = 265,152 t Quantity of calcium carbonate in the earth used: MCaCO3 = 265,152 × 0.15 = 39,773 t 100 g of calcium carbonate provides 44 g of carbon dioxide (molar masses). The mass of carbon dioxide that results from the decarbonation of the earth is: E2.1 = 39,773 × 44 / 100 E2.1 = 17,500 t CO2 6.1.3.2.2. Combustion of the sawdust incorporated into the paste The self-ignition temperature of the wood is of the order of 300°C. The combustion of sawdust particles in the earth at the start of firing liberates carbon dioxide. However, these emissions do not need to be counted, because they correspond exactly to the quantity of CO2 that is sampled from the atmosphere by the regeneration of wood (photosynthesis). E2.2 = 0
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REMINDER.– The emissions from the production of sawdust need to be included in the inputs group. Sub-total direct emissions not related to energy: E2 = 17,500 ± 3% t CO2e (17,500) 6.1.3.3. Emissions due to the production of inputs 6.1.3.3.1. Earth Here, there is no need to count the emissions related to the supply of earth, since this is part of the company activity and the various contributions are allocated across all the groups involved. 6.1.3.3.2. Sawdust The emissions factor for sawdust is not given by ADEME. It is therefore necessary to make an estimate for it. The simplest solutions would be to consider the sawdust to be a product of the wood industry and to associate it with the same emissions factor as the other products, in other words, 36.7 kg CO2e/t [ADE 18b]. Nevertheless, it is possible to allocate the emissions of transformation of wood to the products, by-products and waste, using the argument of the market value or the relative quantity. Criteria of the market value A metric ton of sawdust costs approximately €30 [ESA 18]. The price of timber varies greatly depending on the use. As an indication, a cubic meter of construction wood for frames costs 250 (fir tree) to 600 (oak) euros, in other words, about 550–850 euros per metric ton (fir tree: 450 kg/m3; oak: 700 kg/m3). The ratio of sawdust/wood market value is of the order of 4%. Criteria of the relative quantities In France, in 2016, production of timber, industrial wood and wood used for energy was 37,942 metric kilotons. Sawdust (2,133 kt) represents 6% of this tonnage. The two methods restitute a ratio of the same order of magnitude, and we will select the value of 5% as a multiplication coefficient of the emissions factor of timber, in other words: EFsawdust = 36.7 × 0.05 = 1.835 EFsawdust = 2 kg CO2e/t
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Climatic Impact of Activities
The production emissions of 40,000 metric tons of sawdust are: E3.1 = 40,000 × 2 / 1,000 E3.1 = 80 t CO2e 6.1.3.3.3. Engine oil Oil tonnage: 500 × 0.840 / 1,000 = 0.420 t. The Base Carbone® does not give an emissions factor for manufacturing of engine oil. Taking into account the modest quantities of emissions at hand, in comparison to the other sources in this balance, it is not useful to implement a sophisticated estimation method. Since the engine oil is a petrochemical product, we will assimilate it to a plastic with a high emissions factor (5,500 kg CO2e/t, to the nearest 20%). E3.2 = 0.420 × 5,500 / 1,000 = 2.5 t CO2e 6.1.3.3.4. Parts for machinery and machines E3.3 = 1.75 × 5,500 / 1,000 = 10 t CO2e Sub-total manufacturing of inputs: E3 = 100 ± 17% t CO2e (93). 6.1.3.4. Emissions due to inputs for brick packaging In contrast to other inputs in general, the inputs for product packaging are future waste whose future is statistically known in various processing routes. Hence, it is possible to count at this point not only the emissions related to production of materials for brick packaging, but also their end of life (take care not to take them into account in the balance group dedicated to end of life). The bricks are arranged on pallets; each batch on pallets is encircled by steel bands and wrapped in a low-density polyethylene cover. The number of pallets is therefore the parameter to be decided first. Each one contains 1,260 kg bricks. Number of pallets required for annual production: Np = 250,000 × 1,000 / 1,260 = 198,413 pallets
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6.1.3.4.1. Manufacturing of wooden pallets A pallet weighs 18 kg. Total tonnage of pallets: Pp = 198,413 × 18 / 1,000 = 3,571.4 t E4.1 = Pp (EFmanufacturing + EFendLife) E4.1 = 3,571.4 (38 + 33) / 1,000 E4.1 = 254 t CO2e 6.1.3.4.2. Encircling steel Steel tonnage: Pa = 198,413 × 1.1 / 1,000 = 218.3 t The emissions factors provided are for new steel and recycled steel: EFmanufacturing new steel = 3,190 kg CO2e/t EFmanufacturing recycled steel = 1,100 kg CO2e/t With a recycled content of 40%, the emissions factor for the encircling steel is: EFmanufacturing = 0.60 × 3,190 + 0.40 × 1,100 = 2,354 kg CO2e/t E4.2 = Pa (EFmanufacturing + EFendLife) E4.2 = 218.3 (2,354 + 33) / 1,000 E4.2 = 521 t CO2e 6.1.3.4.3. Polyethylene covers Tonnage of polyethylene: Ppe = 198,413 × 0.8 / 1,000 = 158.7 t E4.3 = Ppe (EFmanufacturing + EFendLife)
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Climatic Impact of Activities
E4.3 = 158.7 (2,090 + 880) / 1,000 E4.3 = 472 t CO2e Sub-total packaging inputs: E4 = 1,500 ± 20% t CO2e (1,247). 6.1.3.5. Emissions due to the transport of materials and merchandise The transport is differentiated between: – internal transport (earth from the quarries to the brickworks and return of part of the brick waste to the quarries); – previous transport for supplies (sawdust, fuel and combustible materials); – later transport for delivery of bricks to the clients. 6.1.3.5.1. Internal transport The quantity of earth transported by rotation is 17 metric tons. The container trucks required therefore belong to the GVWR category 21.1–32.6 metric tons. Number of rotations of trucks (Nt) to transport the earth: Nt = T / 17 = 265,152 / 17 = 15,598 rotations The load transported on the way corresponds to the payload capacity and the trucks return empty to the quarries, except when the brick waste is evacuated, in which case the trucks are full for the entire rotation. Number of loads of broken bricks carried to the quarries for infill: of the 2,525 metric tons of broken bricks, only 35% are used as infill: Ndb = 0.35 × 2,525 / 17 = 52 loads Case 1: earth + return empty Earth transport is carried out by a rented fleet of trucks. Fuel consumption is included in the rental and is not known (hence: VKm, TKm1 or TKm2 method): α = 50% and β = 100% The distance quarry–brickworks (dcb) is 18 km.
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The transport conditions are the same; therefore, the kilometerage can be cumulated: Da = (Nt – Ndb) (2 dcb) Da = (15,598 - 52) × (2 × 18) = 559,656 km Calculation of emissions using the VKm method (see section 4.4.1.3.1): EFvkm = β (1 - α) (EFC - EFV) + EFV + EFF Although the trucks do not belong to the company, production emissions will be counted in the fixed assets group (EFF = 0 in this expression): EFvkm = β (1 - α) (EFC - EFV) + EFV E5.1a = Da . EFvkm E5.1a = Da (β (1 - α) (EFC - EFV) + EFV) E5.1a = 559,656 × [1 × (1 - 0.5) (1.572 - 1.092) + 1.092] / 1,000 E5.1a = 746 t CO2e Case 2: earth + brick waste α = 0% and β = 100% Since the transport conditions are the same, the kilometerage can be cumulated: Db = Ndb (2 dcb) = 52 × (2 × 18) = 1,872 km EFvkm = β (1 - α) (EFC - EFV) + EFV E5.1b = Db . EFvkm E5.1b = Db (β (1 - α) (EFC - EFV) + EFV) E5.1b = 1,872 × [1 × (1 - 0) (1.572 - 1.092) + 1.092] / 1,000 = 3 t CO2e Since the transport of waste is counted in the relevant group, half of these emissions are attributed to the transport of earth (the other half, in other words, 1.5 t CO2e, is attributed to the “waste” group).
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Climatic Impact of Activities
Emissions from internal transport represent: E5.1 = E5.1a + E5.1b / 2 E5.1 = 748 t CO2e 6.1.3.5.2. Previous transport Sawdust Transport of sawdust is carried out by a rented fleet of semi-trailers. The consumption of fuel is included in the rental and is unknown (hence: VKm, TKm1 or TKm2 method). For sawdust with low density (350 kg/m3), it is necessary to check the weight of a complete load. The service volume of the semi-trailer (75 m3) represents a tonnage of sawdust (75 × 350 / 1,000 = 26.25 metric tons) that is greater than the gross vehicle weight rating (25 t). The maximum sawdust loading is therefore 25 metric tons, and β is 100%. We know that the trucks return empty (α = 50%) and the distance traveled (Ds) can be calculated. We will therefore use the calculation method VKm (see section 4.4.1.3.1): EFvkm = β (1 - α) (EFC - EFV) + EFV + EFF Although the trucks do not belong to the company, the manufacturing emissions will be counted under the fixed assets group (EFF = 0 in this expression): EFvkm = β (1 - α) (EFC - EFV) + EFV Since the annual quantity is 40,000 metric tons, the number of rotations is: Ns = 40,000 / 25 = 1,600 rotations The distance ds from the sawdust loading point is 42 km: Ds = Ns (2 ds) = 1,600 × (2 × 42) = 134,400 km E5.2a = Ds . EFvkm E5.2a = 134,400 × [1 × (1 - 0.5) (1.311 - 0.911) + 0.911] / 1,000 E5.2a = 150 t CO2e
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As an example, the uncertainty for this value is calculated in section 4.10, “Calculation of uncertainties”. Heavy fuel oil The heavy fuel oil for drying and firing of the bricks is carried by transporters with semi-trailer tankers with a capacity of 38,000 liters. The semi-trailer will be loaded to its maximum load and not the maximum it can contain because 38,000 liters of heavy fuel oil (volumetric mass, 1,000 kg/m3) would weigh 38 metric tons, which would exceed the authorized load (25 t): β = 100%. The distance between the supplier and the brickworks is known (40 km), and it is known that the trucks are empty on the return journey (α = 50%). The VKm method can be used. Number of rotations of semi-trailer tankers: Nfl = 19,100 / 25 = 764 rotations Dfl = 764 × (40 × 2) = 61,120 km Carbon amortization of trucks must be counted at this point because the company has neither financial control nor operational control (not included in the fixed assets group). EFvkm = β (1 - α) (EFC - EFV) + EFV + EFF E5.2b = Dfl . EFvkm E5.2b = 61,120 × [1 × (1 - 0.5) (1.311 - 0.911) + 0.911 + 0.110] / 1,000 E5.2b = 75 t CO2e Diesel Diesel for the vehicles is carried by transporters with tankers with a capacity of 12,000 liters (PC max = 11 t). Annual consumption is 10,000 liters. Since the load weight is (10,000/1,000) × 0.850 = 8.5 metric tons, the maximum load is less than the payload capacity: β = 8.5 / 11 = 0.77
106
Climatic Impact of Activities
The return journey is carried out when empty: α = 50%. One rotation is sufficient (distance: 40 km): Dg = 1 × (40 × 2) = 80 km The VKm method can be used (see section 4.4.1.3.1), and the emissions factors are those in the truck category GVWR 11-19 t. Carbon amortization of the truck must be counted at this point, because the company has neither financial control nor operational control (not included in the fixed assets group). EFvkm = β (1 - α) (EFC - EFV) + EFV + EFF E5.2c = Dg . EFvkm E5.2c = 80 × [0.77 × (1 - 0.5) (1.084 - 0.753) + 0.753 + 0.075] / 1,000 E5.2c = 0.076 t CO2e The emissions from previous transport represent: E5.2 = E5.2a + E5.2b + E5.2c E5.2 = 225 t CO2e 6.1.3.5.3. Later transport Bricks are delivered to the clients by semi-trailer, but the exact transport conditions are unknown. In this type of case, the TKm1 method is indicated. The calculation is made using the tonnage transported only on the outward delivery journey, with statistical values for α and β. The emissions factor has been calculated in Table 4.3 and is: EFtkm = 0.107 kg CO2e/t.km E5.3 = T . d . EFtkm – Departmental transport: E5.3a = 20,500 × 50 × 0.107 / 1,000 = 110 t CO2e – Transport to neighboring departments: E5.3b = 80,250 × 100 × 0.107 = 859 t CO2e
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– Regional transport (except for neighboring departments): E5.3c = 102,700 × 180 × 0.107 = 1,978 t CO2e – National transport (except for regional transport): E5.3d = 46,550 × 500 × 0.107 = 2,490 t CO2e The total emissions for brick delivery transport are: E5.3 = E5.3a + E5.3b + E5.3c + E5.3d E5.3 = 5,437 t CO2e Emissions from transport of merchandise: E5 = E5.1 + E5.2 + E5.3. Sub-total for transport of merchandise: E5 = 6,500 ± 10% t CO2e (6,410). 6.1.3.6. Emissions due to movement of people 6.1.3.6.1. Journeys residence–work Observation (see the table of data in section 6.1.2, under the heading “Emissions due to the transport of merchandise”): – 49 people answered the investigation, whereas the workforce is made up of 72 employees; – the five company cars feature in the sample; – four employees who answered the investigation make the journey on foot or on a bicycle. It is necessary to extrapolate the distances traveled on an annual basis by the vehicles between places of residence and the brickworks to the total workforce, using the known information available for a reduced sample. The case of pedestrians, cyclists and company cars complicates the processing. Effectively: 1) we do not know if, amongst the personnel who have not answered the investigation, there are cyclists and pedestrians or not; 2) the contribution made by company cars is also treated as part of professional journeys, by taking into account their overall consumption, including journeys from residences to work. It is therefore necessary to make hypotheses, but they are not unequivocal. In a first instance, it would be necessary to examine the incidence of these hypotheses on the emissions result. However, the perspective of these laborious calculations must
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Climatic Impact of Activities
encourage an appraisal of the main issues that result in this emission group having an incidence on the balance. A very approximate estimate, for all vehicle categories together, gives an annual cumulated kilometerage (220 working days) of the order of 500,000 kilometers. An average emissions factor of 0.25 kg CO2e/km would give an emission amount of the order of 125 t CO2e. With just these, the emissions calculated for the previous groups is about 100,000 metric tons of equivalent CO2. With regard to this figure, the contribution of the journeys between places of residence and the brickworks is negligible. We could very well be content with this estimate, with an uncertainty evaluated at 20%. From an educational point of view, it is useful all the same to understand the method of calculating emissions related to journeys between places of residence and the workplace, on the basis of a sample collected through an inquiry, in anticipation of situations where this group would be significant, or even dominant. Yet, in this exercise, the students regularly set out hypotheses that are different from those chosen by the teacher! It is therefore of some use to examine all the possible hypotheses to analyze the sensitivity of the result to the choice of one of them. The details of this analysis are given in Appendix 4. This shows that the emissions related to private journeys vary in the range ±10% according to the hypotheses made. Through this, it is noted that the choice a priori of a scenario, made knowingly or by omission of a certain number of possible cases, would not lead to bypassing of the estimate of the emissions related to the journeys between residences and the brickworks, in this particular case. In summary, it is necessary to bypass fastidious and useless calculations, but in all lucidity, and to nevertheless be able to construct rigorous reasoning when the stakes at play in association with the emission amounts are significant. In broad terms, we can define the estimated value by: E6.1 = 125 ± 20% t CO2e (the calculation in Appendix 4 restitutes 120 ± 10% t CO2e) 6.1.3.6.2. Journeys made for work Journeys by car It is sufficient to multiply the quantity of diesel consumed, with a deduction for the journeys made between the place of residence and the brickworks (see the calculation in Appendix 4), by the emissions factor for diesel (combustion + previous). E6.2a = (10,124 - 3,432) × (2.51 + 0.657) / 1,000 E6.2a = 21 t CO2e
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Journeys by air Do not forget to multiply the distances between airports by 2! These distances are given by online calculators. – Emissions from journeys by air between Paris and New York: E6.2b1 = (5,844 × 2) × 3 × 0.230 / 1,000 E6.2b1 = 8 t CO2e – Emissions from journeys by air in France: E6.2b2 = (500 × 2) × 9 × 0.453 / 1,000 E6.2b2 = 4 t CO2e Total emissions related to journeys by air: E6.2b = E6.2b1 + E6.2b2 E6.2b = 12 t CO2e Journeys by train Do not forget to multiply the distance by 2 to take into account the return journeys! E6.2c = (500 × 2) × 23 × 3.69.10-3 / 1,000 = 0.085 t CO2e E6.2c is negligible in the context of emissions related to journeys. The total emissions related to journeys for work are: E6.2 = E6.2a + E6.2b + E6.2c E6.2 = 33 t CO2e Sub-total journeys by people: E6 = E6.1 + E6.2 = 160 ± 15% t CO2e (158)
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Climatic Impact of Activities
6.1.3.7. Emissions due to the transport and treatment of waste 6.1.3.7.1. Brick waste Refer to the paragraph “Internal transport” for the detailed calculation. Emissions related to the transport of 884 metric tons of brick waste to the quarries: E7.1a = E5.1b / 2 = 1.5 t CO2e The rest of the broken bricks, that is, 2,525 - 884 = 1,641 metric tons, is sent to a landfill site: E7.1b = 1,641 × 33 / 1,000 = 54 t CO2e E7.1 = E7.1a + E7.1b E7.1 = 56 t CO2e 6.1.3.7.2. Used engine oils The Base Carbone® [ADE 18b] does not provide an emissions factor for treatment of this waste. We know that the used engine oils are incinerated in cement works for energy repurposing and, from that point on, we can make use of exercise 4.2, section 4.6, where it had been determined as of the order of 2,700 kg CO2e/t in the case of incineration. Tonnage of oil: 500 × 0.840 / 1,000 = 0.420 t. E7.2 = 0.420 × 2,700 / 1,000 E7.2 = 1.1 t CO2e 6.1.3.7.3. Packaging plastics E7.3 = Q . EFincineration = 1 × 2,680 / 1,000 E7.3 = 2.7 t CO2e As an example, the uncertainty for this value is calculated in section 4.10: “Calculation of uncertainties” (section 4.10).
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6.1.3.7.4. Packaging boxes Emissions from the processes preceding the transformation into new paper paste are considered here. The emissions factor to be considered for the end of life is then the same as for storage (see exercise 4.1, section 4.6). E7.4 = Q . EFstorage = 2 × 983 / 1,000 E7.4 = 2 t CO2e Sub-total treatment of waste: E7 = 60 ± 25% t CO2e (62). 6.1.3.8. Emissions due to manufacturing of fixed assets Emissions from manufacturing of fixed assets are not totally included in the annual balance. They are spread over a period of time that corresponds classically to the duration of accounting amortization, and the annual ratio is written on the balance. When the lifetime of the assets exceeds the duration of amortization, no further emissions need to be counted. We have selected the following amortization durations: Office
25 years
Industrial buildings
20 years
Roads
30 years
Machines
10 years
Equipment
10 years
Automobiles
5 years
Trucks
5 years
Furniture
10 years
Computer equipment
3 years
Office equipment
3 years
ATTENTION.– Do not forget to divide the emissions from manufacturing of assets by the duration of amortization. (A)
(B)
(C)
Offices
32 | 25
Amortized
0
Industrial buildings
15 | 20
10,000 × 275 / 1,000 = 2,750
137.5
Car parks and roads
20 | 30
10,000 × 73 / 1,000 = 730
24
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Climatic Impact of Activities
Machines, industrial equipment
15 | 10
Amortized
0
Automobiles
3|5
6 × 5,500 / 1,000 = 33
6.6
Trucks
7|5
Amortized
0
Old office furniture
15 | 10
Amortized
0
Recent office furniture
3 | 10
5 × 1,830 / 1,000 = 9.2
0.9
CRT screen computers
5|3
Amortized
0
Flat screen computers
2|3
15 × 1,280 / 1,000 = 19.2
6.4
Printers
2|3
5 × 110 / 1,000 = 0.6
0.2
Photocopiers
2|3
1 × 2,940 / 1,000 = 2.9
1.0
---------------------------------------------------------------------------------------------------------Notations (A)
Age | Duration of amortization (year)
(B)
Emissions from manufacturing (t CO2e)
(C)
Carbon amortization = B/A (t CO2e/yr)
Sub-total for carbon amortization of fixed assets: E8 = 180 ± 23% t CO2e (175) 6.1.3.9. Emissions due to the use of bricks In section 4.8, “Emissions due to the use of products”, the case of the use of concrete blocks was examined. The reasoning applies just as much to bricks as to fired earth, which provides the same function in construction. We had established that the use of such construction materials requires: – mortar for fixing in place; – an external rendering; – an internal doubled layer (without insulation, in the case of bricks with high thermal performance that are relevant here); – installation of protective roofing; – this use therefore conditions the consumption of energy for the lifetime of the building.
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Calculation of the surface area of walls constructed with annual production as follows: – Tb : annual production of bricks; – Wb: weight of a brick; – Nb: number of bricks per square meter of wall; – Sw: surface of wall that can be constructed with the annual production. Sw = (Tb / Wb) / Nb Sw = (250,000 × 1,000 / 18) / 16.5 = 841,751 m2 6.1.3.9.1. Emissions due to the use of mortar Quantity of mortar required to set the bricks in place (5 kg/m2): Qm = 841,751 × 5 / 1,000 = 4,209 t Calculation of the emissions factor for mortar (sum of the emissions factors of the constituents in their relevant proportions): EFmortar = (0.39 × 866) + (0.44 × 2.32) + (0.17 × 0.132) = 339 kg CO2e/t E9.1 = 4,209 × 339 / 1,000 E9.1 = 1,427 t CO2e 6.1.3.9.2. Emissions due to the use of external rendering (EF = 4.96 kg CO2e/m2) E9.2 = (841,751 × 4.96) / 1,000 E9.2 = 4,175 t CO2e 6.1.3.9.3. Emissions due to internal layering The manufactured bricks have high thermal performance and do not require additional insulation (see the exercise in section 5.3). Insulation layering is in fact a coating of plaster panels glued to the base with cement-glue, and finishing of joints with joint tape and plastering.
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Climatic Impact of Activities
Plaster panels, joint tape and plastering E9.3a = 841,751 × 2 / 1,000 = 1,684 t CO2e Cement-glue The INIES database does not provide lifecycle analysis for the cement-glue. We will suppose that its emissions factor is of the order of final plaster applied to plaster panels (0.169 kg CO2e/UF); in other words, 583 kg CO2e/t [PLA 15]. Estimated emissions factor for cement-glue: 600 ± 30% kg CO2e/t. Quantity of cement-glue required for installation of plaster panels: Mcg = 841,751 × 2.5 / 1,000 = 2,104 t E9.3b = 2,104 × 600 / 1,000 = 1,262 t CO2e E9.3 = E9.3a + E9.3b = 1,684 + 1,262 E9.3 = 2,946 t CO2e 6.1.3.9.4. Emissions due to roofing Roofing is required for protection of the walls, but emissions will be allocated in proportion to the surface area of roofing which is in line with the walls, in other words, about 0.75 m2 per meter of wall including the overhang. We know the area of constructible wall from the annual production of bricks (this is 841,751 m2), but the heights are highly variable, ranging from an individual house to a building for collective housing, or around the external perimeter of a construction from the facades to the gables, for example. Reconstitution of the linear distance of the walls is therefore uncertain and comes from a very approximate estimate. For an average estimated height of 8 m, the linear distance may represent 105,000 m, giving an order of magnitude of 79,000 m2 of roofing dedicated to protection of the walls. The emissions related to the framing and tiles for this surface area would be: E9.4 = 79,000 × (1.1 + 14.3) / 1,000 E9.4 = 1,200 t CO2e
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6.1.3.9.5. Emissions due to energy consumption No data have been provided: it was up to you to find out the right information! Here, it is necessary to estimate the energy losses of the real estate constructed using brick production in one year (250,000 t), over the lifetime of the buildings (another method could consist of evaluating the energy loss for a year, but for the entire existing real estate, constructed previously with bricks from the company). It is presumed that the constructions comply with the standard RT 2012 extended on January 1, 2018. The average demand in primary energy is 50 kWh/m2.yr (57.5 kWh/m2.yr for the communal buildings) [LEG 10], without taking into account the modulation coefficients for this estimate. We estimate the surface area of the walls to be approximately 200 m2 for 100 m2 of inhabitable floor space. Inhabitable constructed surface area (Sh) with the annual production of bricks: Sh = Sw × 100 / 200 = 420,876 m2 Energy consumed in a year: W = 420,876 × (50.10-6) = 21 GWh/yr For a lifetime of 50 years: W50 = 1,000 GWh Rate of loss through the walls: 15%. Leaked energy: Wl50 = 1,000 × 0.15 = 150 GWh Depending on the actual distribution of the means of heating [ADE 18c], with the hypothesis (improbable) that these proportions are constant, the emissions would be:
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Climatic Impact of Activities
Wl50
EF
E
(GWh)
(kg CO2e/kWh LCV)
(t CO2e)
Natural gas
32.2%
48.3
0.243
11,700
Fuel
18.5%
27.8
0.324
9,000
LPG
2.5%
3.8
0.272
1,000
Electricity
38.7%
58.1
0.0647
3,800
Wood
7.4%
11.1
0.03
350
Urban heating 0.4%
0.6
0.1
60
Coal
0.6
0.377
230
0.4%
Total
26,140
E9.5 = 26,140 t CO2e Sub-total use of bricks: E9 = 36,000 ± 30% t CO2e (35,888). 6.1.3.10. Emissions due to the end of life of bricks We make the hypothesis that at the end of life, demolition bricks loaded with mortar, rendering and plaster will be deposited in a landfill site under the current situation. Tonnage of bricks and adherent materials: – bricks: 250,000 t; – cement for fixing (quantity already calculated under the “use” group): 4,209 t; – external plastering: wall surface (Sw) × surface weight of rendering: 841,751 × 24 / 1,000 = 20,202 t – plaster panels and cement-glue: wall surface (Sw) × surface weight: 841,751 × (9.3 + 2.5) / 1,000 = 9,933 t Total tonnage: 284,344 t. For calculation of the emissions related to the treatment of waste, we have seen that the emissions factor related to the deposition of inert materials in a landfill site was 33 kg CO2e/t.
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For future waste from the demolition of buildings constructed with 250,000 metric tons of bricks, these emissions would be: E10 = 284,344 × 33 / 1,000 Sub-total for end of life of bricks: E10 = 10,000 ± 35% t CO2e (9,383). 6.1.4. Recap of the quantification of emissions The total annual direct and indirect emissions generated by the activity of the brickworks represent approximately 143,000 ± 8% metric tons of carbon dioxide equivalent. Emissions groups
Emissions t CO2e
%
Uncertainty (%)
Use of energies
71,000
49.7
Direct non-energy emissions
17,500
12.2
3
100
0.1
17
Production of “packaging”
1,500
1.0
20
Transport of merchandise
6,500
4.5
10
Journeys made by people
160
0.1
15
Production of inputs
Waste treatment
4
60
0.04
25
180
0.1
23
Use of bricks
36,000
25.2
30
End-of-life of bricks
10,000
7.00
35
100
8
Production of fixed assets
Total
143,000
Figure 6.3. Emissions of greenhouse gases, both direct and indirect, per group, due to the activity of the brickworks. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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Climatic Impact of Activities
6.1.5. Recommendations The dominant emissions are due to the following processes: – firing of bricks; – use of bricks; – decarbonation of clay; – end of life of bricks; – transport of merchandise. 6.1.5.1. Recommendations to reduce the energy emissions Substitution of all or part of the heavy fuel oil by another combustible material of fossil origin, which leads to lower emissions, or by a plant or biogenic combustible, must be studied. 6.1.5.1.1. Case 1: energy repurposing of waste of fossil origin The main question specified the nature of the activities of other companies located on the same industrial estate as the brickworks, in particular the existence of a used tire collection activity. Incineration of used tires for energy repurposing is authorized by law in France. The Code de l’Environnement [LEG 18, article R543-140] stipulates that: “All collected tire waste must be treated in the following ways, prioritizing in order: 1. preparation with a view to re-use; 2. recycling; 3. other methods of repurposing, including energy repurposing”. This type of combustion installation is associated with technical and administrative constraints that need to be studied. Is substitution of heavy fuel oil by tires valid from the point of view of carbon dioxide emissions? The lower calorific value of tires is on average [CLA 09, p. 7] 30.2 and 26.4 MJ/kg in the case of light vehicles (LV) and heavy good vehicles (HGV) respectively. In 2016, the tonnage of tires on the French market was 368,990 and 101,061 metric tons for LVs and HGVs respectively [SAL 17, p. 23]. We make the hypothesis of an identical ratio at the waste stage, which means an average lower calorific value can be evaluated: LCVt = [(368,990 × 30.2) + (101,061 × 26.4)] / (368,990 + 101,061)
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LCVt = 29.4 GJ/t We know that the LCV for heavy fuel oil is 40.5 GJ/t and that the annual consumption is 19,100 t. Quantity of tires required to provide the same quantity of energy: Qt = 19,100 × 40.5 / 29.4 = 26,311 t The emissions factor for combustion of tires is 85 ± 20% kg CO2/GJ LCV [ADE 18b]. Emissions factor for combustion of tires in kg CO2/t: EFt = ((85 × 1,000) × 29.4) / 1,000 = 2,500 kg CO2/t Emissions from combustion of tires: Et = 26,311 × 2,500 / 1,000 = 65,778 t CO2e Emissions from combustion of heavy fuel oil was 70,000 (69,524) t CO2e. The difference is not significant and not interpretable, given the uncertainties. Substitution by tires does not seem to be useful from the point of view of the climate impact. On the other hand, the price of shredded tires, lower than the price of heavy fuel oil, can present an economic advantage. In this case, we can confirm that the conversion will not lead to an increase in emissions. However, combustion of tires emits other pollutants, even with fume treatment installations that comply with standards. The neighbors would be right to worry, and the image of the brickworks could suffer. Fortunately, more profitable options are possible. 6.1.5.1.2. Case 2: substitution of heavy fuel oil by natural gas The Base Carbone® gives the following emissions factors: – heavy fuel oil: EFfl = 91.2 kg CO2e/GJ LCV; – natural gas: EFng = 67.4 kg CO2e/GJ LCV. The quantity of energy to provide for firing the bricks represents (calculation based on the quantity and the LCV of heavy fuel oil): W = 19,100 × 40.5 = 773,550 GJ
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Climatic Impact of Activities
With natural gas, the corresponding emissions would be: Eng = EFng . W Eng = 67.4 × 773,550 / 1,000 = 52,137 t CO2e The related reduction in emissions would therefore represent: ∆E / E0 = (Efl - Eng) / Efl ∆E / E0 = (69,524 - 52,137) / 69,524 = 25% 6.1.5.1.3. Case 3: substitution of heavy fuel oil by wood (sawdust or wood chips) NOTATIONS.– EF: emissions factor for combustion (with previous). E: emissions related to the combustion of combustible materials. LCV: lower calorific value of the combustible material. M: tonnage of the combustible material. f: identifier for heavy fuel oil. w: identifier for wood. Mf0: tonnage of heavy fuel oil in the initial situation (100% of heavy fuel oil). MfW: tonnage of heavy fuel oil substituted by wood. MfR: tonnage of residual heavy fuel oil still used in addition to the wood. α: rate of substitution of heavy fuel oil by wood. α = MfW / Mf0 MfW = α Mf0
[6.1]
MfR = (1 - α) Mf0
[6.2]
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Due to the differences in calorific values, a mass of wood greater than that of fuel oil will be necessary. The energy equivalent is given by: Mw . LCVw = MfW . LCVf Mw = MfW (LCVf / LCVw) According to [6.1]: Mw = α Mf0 (LCVf / LCVw)
[6.3]
The emissions from combustion relate to wood and the residual fuel oil and are: E = EFf . MfR + EFw . Mw According to [6.2] and [6.3]: E = EFf (1 - α) Mf0 + EFw α Mf0 (LCVf / LCVw) E = EFf . Mf0 - α Mf0 [EFf - EFw (LCVf / LCVw)] Mf0 = 19,100 t (see section 6.1.1) LCVf = 40.5 MJ/kg (see section 6.1.1) LCVw = 15 MJ/kg (bibliographic data) EFf = 3,640 kg CO2e/t (see section 6.1.1) EFw = EFwA + EFwCOMB (previous (production of wood and transformation) + combustion) EFwA = 2 kg CO2e/t (see section 6.1.3.2.2, the calculation of sawdust production emissions) Combustion of sawdust from French regenerated forests does not lead to additional greenhouse gas emissions because they correspond exactly with the carbon dioxide taken from the atmosphere by photosynthesis: EFwCOMB = 0 EFw = 2 kg CO2e/t
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Climatic Impact of Activities
E = (3,640 × 19,100 - 19,100 [3,640 - 2 (40.5/15)] α) / 1,000
(t CO2e)
E = 69,524 - 69,421 α
(t CO2e)
The total substitution (α = 100%) by wood nearly cancels out the emissions due to combustible materials: Ew100% = 103 t CO2e The incidence due to transport of sawdust remains to be studied. Tonnage of sawdust required for total substitution: According to [6.3]: Mw = α Mf0 (LCVf / LCVw), with here α =100% Mw = 19,100 × 40.5/15 = 51,570 t We have calculated that the transport of 40,000 metric tons of sawdust emits 150 t CO2e (E5.2a). If all other conditions are equal, the increased emissions due to supply transport would be: 150 × 51,570 / 40,000 = 194 t CO2e, from which the cancelation of the emissions for final transport of heavy fuel oil (E5.2b = 75 t CO2e) needs to be deduced, meaning a resultant of ETw = 119 t CO2e. The relative reduction would represent: ∆E / E0 = (E0 - Ew100% - ETw) / E0 = (69,524 - 103 - 119) / 69,524 that is, 99.6%. Notwithstanding the amortization of the required investments, the substitution of heavy fuel oil by wood would allow the cost of production to be reduced because even if a tonnage of wood that is three times greater is required, its cost is of the order of €30/t [ESA 18], in other words, of the order of magnitude of 15–20 times less than for heavy fuel oil [MIN 18]. However, it would remain necessary to check that a supply of 51,570 metric tons of sawdust, in addition to the 40,000 metric tons incorporated into clay, would remain locally possible. 6.1.5.2. Recommendations to reduce the emissions due to the use of bricks The primary cause of emissions related to the use of bricks is the losses of heat through the walls. Improvement will be made by increasing the thermal resistance of the fired earth. If it is the case that this is possible, an in-depth technical discussion with competent persons would be necessary, except for more in-depth reconsideration of the nature of the material, which will be evoked below, in the
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discussion of the emissions from processes related to the impurity of the calcium carbonate in the earth. 6.1.5.3. Recommendations to reduce the emissions due to decarbonation of the earth: development of a new bio-sourced brick with low gray energy The clay firing process (combustion and decarbonation) is responsible for 61% of all the emissions due to the activity. A process which avoids bringing the material to a temperature of 1,000°C would be a considerable improvement from the point of view of the climate impact. Raw earth or bio-sourced materials naturally come to mind: straw (houses, as well as buildings with upper floors have already been constructed from straw); lime-hemp bricks, etc. The idea would be to develop a parallel experimental production and pilot, with a view to progressive substitution. The investments for these productions would also be quite modest. For lime-hemp bricks, we will be able to consult another brickworks case study, examined in the context of complex engineering [ROS 18]. Let us add a few technical specifications however, concerning the environmental advantage of this type of brick. It is a composite material made up of fragments of hemp stem (hemp stem chips), embedded in a matrix of lime mortar. This brick has excellent insulating properties, and it is lighter and more permeable to steam than fired earth bricks. However, it is less resistant in compression than traditional brick, which means it is used for filling wood frames rather than for load-bearing roles. An enormous advantage over fired earth brick lies in the fact that it can be a carbon sink1, because it is mainly made up of plant material. We specify that the contribution of the binding medium is low because the setting of the lime takes place with a chemical reaction that is inverse to the reduction of limestone, applied for production, with reabsorption of an equal quantity of carbon dioxide. In addition, lime-hemp bricks require less energy than their fired earth rival. Effectively, the quantity to heat to high temperatures (900°C) does not refer to all the material, as is the case with fired earth brick, but only for the 7% of the volume of the lime-hemp brick that represents the lime. The ultimate advantage of the lime-hemp brick is to be able to constitute, at end of life, an agricultural amendment, due to its carbonated composition and the organic and biodegradable nature of hemp straw. 1 “The results demonstrate a potential favorable impact with regard to the greenhouse effect. Thus, the life cycle of a square meter of wall in hemp concrete for 100 years stores between 14 and 35 kg CO2 eq per m2, depending on the massive or economical allocation. This storage of carbon is mainly due to the hemp stem chips content, as well as to the wood, and the lime in the concrete (recarbonation phenomenon)” [BOU 05, p. 5]. Remark: this second reasoning is erroneous because the reduction of calcium carbonate in the lime kiln had released the same quantity of carbon dioxide as that at stake in recarbonation
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Climatic Impact of Activities
Traditional production of lime-hemp bricks and the fact that it has remained confidential lead to an increased cost of about 4% for an individual house. Scale economies remain to be examined for mass production. In addition, the mechanical resistance of bricks does not allow load-bearing walls to be put up. Lime-hemp bricks must fill a wooden structure constructed on columns. This particularity appears to indicate a change in building practices. 6.1.5.4. Other recommendations – Packaging covers for the pallets, in new polyethylene, could come from the sector of recycled polyethylene. With a decrease in the emissions factor from 2,090 to 202 kg CO2e/t for an annual quantity of 159 metric tons, the potential for reduction is: (2,090 - 202) × 159 / 1,000 = 300 t CO2e. – The brick waste sent to a landfill site could be repurposed as granular materials in the production of concrete, or, if it is finely ground, it can be recycled in production mixed with clay (this is practiced in reality). The maximum potential for reduction is about 25t CO2e, from which the emissions due to energy used for grinding must be deducted. 6.1.5.5. Examination of the proposal to lock away direct emissions of CO2 for production of sodium bicarbonate The question describes the economic environment of the brickworks and mentions the presence of an innovative company whose activity consists of trapping carbon dioxide from significant sources of emissions to synthesize sodium bicarbonate. This has the chemical formula NaHCO3 (sodium hydrogen carbonate). Sodium hydrogen carbonate is not very stable and is soluble in water. For example, in food applications, in particular, chemical raising agents, NaHCO3 decomposes at temperatures of 50°C and re-releases CO2 (this gaseous release makes the mixture swell). In many other applications at low temperatures (hygiene, maintenance, pharmacopeia, etc.), NaHCO3 is dissolved in water and thus transfers to watercourses and the ocean (NaHCO3 represents 95% of oceanic carbon). NaHCO3 is in equilibrium with H2CO3, a compound that is itself in equilibrium with H2O and CO2. The contribution of NaHCO3 tends to disturb the equilibrium so as to cause desorption of CO2. In all cases, trapping of CO2 in the form of sodium bicarbonate is therefore temporary and the carbon dioxide will finish up back in the atmosphere within a very short time. Synthesis of bicarbonate from CO2 cannot be considered to be trapping of carbon and the emissions from the brickworks would not be reduced with implementation of this process: there would simply be delocalization of a direct source of carbon dioxide emissions into an indirect source. However, it is necessary to examine the question in the wider context of standard production of sodium
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bicarbonate. Effectively, if the bicarbonate produced due to capture of CO2 emitted by the brickworks is substituted for bicarbonate from standard production using carbonated mineral resources (e.g. the Solvay process which starts with chalk (CaCO3)), then the substitution would reduce the destockage of CO2 by the standard carbonate sector (Figure 6.4). This potentially favorable observation on the global scale must not dissuade the managers of the brickworks from doing everything in their power to reduce at source the carbon dioxide emissions from the use of fossil energy and carbonated clays. IMPORTANT.– The emissions avoided by good practice must not be deducted from a balance because they are hypothetical and their estimation requires establishment of a reference scenario which can be unrealistic (or even manipulated for convenience), which would bias representation of the physical reality of the emissions and could lead simply to wishful thinking.
Figure 6.4. Capture of carbon dioxide emitted directly by the brickworks for production of sodium bicarbonate does not modify the balance for the brickworks, although with a strict substitution the process can reduce other destockage emissions due to the use of sodium bicarbonate from standard production. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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Climatic Impact of Activities
6.2. Case study 2: vineyard 6.2.1. Description of the activity The activity under study is a vineyard with 20 hectares of vines that produces on average 800 hectoliters (hL) of red wine per year. The winemaking and packaging are carried out by the operator. Figure 6.5 describes the principle of the vinification process.
Figure 6.5. Schematic diagram of a type of vinification. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
6.2.2. Challenge in this exercise To carry out the greenhouse gas emission balance for a vineyard, the calculations can be made according to the model proposed for the brickworks case. The emissions factors can be consulted online [ADE 18b]. Emissions factors specific to the winemaking industry are given in a sectorial guide [INS 11]. The question in this study is to focus thinking on some methodological difficulties.
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6.2.3. Specifications about the activity and questions 6.2.3.1. Inventory and analysis of the sources of CO2 emissions To limit oxidation of the wine, a carbon dioxide atmosphere is injected into the vats, but the activity generates other sources of carbon dioxide. Identify all the phenomena and processes related to the transformation of the winemaking biomass, which generates direct emissions at the scale of the local land area (except for emissions from vehicles and local emissions related to the use and the end of life of wine). Allocate these sources according to the groups defined in Chapter 4 and calculate the amount of emissions for each. 6.2.3.2. Taking into account the emissions from treatment of residues of the winemaking process 1) The dregs and sediment are sent to the company Marly for distillation and composting (legal obligation in France for wine producers, otherwise payment of a tax is required). In addition, the operator buys compost made from distilled dregs as a top-up soil enricher. Analyze all the emissions related to the chain of winemaking residues. 2) The manager of the vineyard does not want the emissions related to distillation to be taken into account in their balance, because the distillery repurposes the dregs and sediment, with sale of alcohol to the State and sale of compost to vine growers, and in that case, Marly has full responsibility for the emissions. What do you think of this? Complete the arguments. 3) The operator of the vineyard has their winemaking residues treated by Marly, which sells the distilled and composted dregs back to them to enrich the vines. The same material therefore appears in the waste group and in the inputs group. Does this cause problematic emissions to be counted twice? 6.2.4. Activity data WARNING.– To put the reader in a more realistic situation – where it is necessary to extract pertinent data from a large quantity, to organize them and to find other information to fill in the blanks – the data related to this case are not classed by type of emission source, they are largely supernumerary and they will also be necessary to find some useful information elsewhere. Information about journeys and transport of merchandise is not provided.
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Climatic Impact of Activities
6.2.4.1. General data Area of vines
20 ha
Average annual production
800 hl
6.2.4.2. Annual flows of the winemaking activity Domestic fuel for agricultural machinery
5,610 l
Assimilation of nitrogen in the soils - factor for evaporation of nitrogen into N2O
0.0209
- GWP (Global Warming Potential) of nitrous oxide
265
Galvanized steel stakes
1,496 kg
Wooden stakes
2,516 kg
Galvanized iron wire
660 kg
Quantity of dregs used as an enricher
80 t
- spreading dose of grape dregs (3-year frequency) Quantity of mineral fertilizer used - composition (in weight) of mineral fertilizer
25 t/ha 800 kg 10/19/9/6 10% N 19% P2O5 9% K2O 6% MgO
Quantity of herbicides used - average proportion of active matter in herbicides Quantity of insecticides used - average proportion of active matter in insecticides Quantity of fungicides used - average proportion of active matter in fungicides
104 kg 35% 26 kg 15% 1,432 kg 58%
Purchase of mechanical oils (engine, hydraulics, axletree, etc.) (d = 0.8)
860 l
Soil analyses
€500
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Vine shoots (shredding and burial of the vines) - nitrogen content of the vine shoots
129
20 t 2.6 kg/t raw product
Hangar for equipment (concrete, 42 years)
130 m2
Straddle tractor (5 years)
2t
Tractor (9 years)
2t
Pulverizer (8 years)
3.5 t
Grape harvesting machine (2 years)
3t
Trailer (13 years)
0.5 t
6.2.4.3. Annual flows in the winemaking activity Volumetric mass of natural gas
0.719 kg/m3
Electricity (2016)
64,012 kWh
Alcoholic fermentation - weight of CO2 released by the alcoholic fermentation
12 kg CO2/hl must
- GWP of carbon dioxide
1
- weight of must harvested per hectare of vines
5,200 kg/ha
- volumetric mass of must
1.070 t/m3
Refrigeration - refrigeration power operating with R407C
30 kW
- Global Warming Potential of R407C
1,624
- refrigeration power operating with R22
18 kW
- Global Warming Potential of R22
1,760
- loading rate of refrigerant for indirect systems at low temperatures in the agri-food industry
3 kg/kW refrigerating
- annual leakage rate of refrigerant for indirect systems at low temperature in the agri-food industry
0.15
CO2 of chemical origin for inert environment in vats
400 m3
Yeasts
13 kg
Sugar
1,720 kg
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Climatic Impact of Activities
Tannins
12 kg
Liquid SO2
160 kg
Filtration earth materials
62 kg
Filtration membranes
48 kg
Egg albumin
22 kg
Caustic soda diluted to 50% (maintenance)
1,709 kg
Phosphoric acid (maintenance)
220 kg
Barrels
104 units
Weight of a barrel
45 kg/barrel
Water supply
400 m3
Enological analyses
€910
Bottling
€850
Glass bottles
73,624 kg
Corks
480 kg
Tin foil outer caps
156 kg
Composite aluminum/LDPE outer caps
320 kg
Aluminum screw caps
32 kg
Labeling
360 kg
Wooden crates with 6 bottles
7,416 kg
Wooden crates with 12 bottles
2,592 kg
Boxes (internal compartments for crates)
592 kg
Printed boxes for 6 bottles
2,784 kg
Printed boxes for 12 bottles
2,640 kg
Pallet binding film (polyethylene)
72 kg
Glue
160 kg
Wooden pallets
1,200 kg
Sediment (distillation)
2t
Dregs (distillation) - composition of grape dregs
12 t 24% of dry material 5.0 kg N/t 0.5 kg P2O5/t 5.8 kg K2O/t 0.3 kg MgO/t
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Effluents treated in wastewater works - quantity | DBO5 | DCO
400 m3 | 21 g/l | 35 g/l
Effluents treated by natural evaporation
200 m3
Glass waste (recycled)
300 kg
Storage-dispatch building (concrete) (7 years)
72 m2
Wine cellar (concrete) (25 years)
1,050 m2
Maintenance hangar (concrete) (42 years)
100 m2
Stainless steel vats (9 years)
10 t
Stainless steel vats (7 years)
8t
Sorting conveyor (7 years)
0.2 t
Press (12 years)
1.5 t
Grape grinder (3 years)
0.1 t
Pumps (10 years)
0.075 t
Rotating filter (5 years)
0.1 t
Bottling chain (3 years)
1.1 t
Metals box (21 years)
9.2 t
Barrels (17 years)
8.0 t
Fork-lift truck (12 years)
1.7 t
6.2.4.4. Annual flows of transverse activities Natural gas for heating premises
207.9 MWh LCV
Purchase of unprinted paper
25 kg
Production of printed documents for communication
100 kg
Various small supplies
€525
Propane for the handling machinery
200 kg
Purchase of mechanical parts
€4,770
Mechanical maintenance
€12,550
Commissions and brokerage
€42,500
Publicity
€18,210
Maintenance of green spaces
€400
Fees for accountants and lawyers
€7,000
Postal costs
€705
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Climatic Impact of Activities
Telecommunication costs
€1,648
Maintenance of plantations
€2,048
Steel waste (recycled)
560 kg
Plastic waste (polyethylene) (recycled)
150 kg
Mixed plastic waste (incinerated)
500 kg
Card and paper waste (recycled)
2,000 kg
Offices (concrete) (30 years)
30 m2
Movement route (cement) (25 years)
120 m2
Movement route and car park (10 years)
240 m2
4x4 vehicle (2 years)
1.8 t
Commercial vehicle (4 years)
1.4 t
CRT screen computer (2 years)
1 unit
Flat screen computer (1 year)
2 units
Photocopier-printer (2 years)
1 unit
Office furniture (21 years)
1,300 kg
6.2.5. Answer to case study 2: winemaking industry 6.2.5.1. Scope of emissions We can examine the system in sub-units related to the main activities summarized in Figure 6.6: – internal (vine-growing, vinification and packaging); – external (supply, dispatch, waste treatment and wine comsumption). The internal activities cause direct emissions (combustion of fossil energy by machinery and the boiler room, fermentation, leaks, etc.) and indirect emissions related to inputs and waste. It may be useful to set up a balance for each internal activity, vinegrowing/vinification/packaging, to analyze the carbon footprint in greater depth and put them together for a global balance, while ensuring that nothing is counted twice.
Figure 6.6. Global scope of direct and indirect emissions related to wine-making activity (only the main flows are represented). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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Climatic Impact of Activities
6.2.5.2. Inventory and analysis of direct sources of CO2 emissions The emissions related to the production of inputs and fixed assets are indirect and are taken into account by their production emissions factor. Direct emissions of carbon dioxide, at the scale of the local territory, related to the processes of transformation of the wine production biomass, are due to combustion of sources of fossil energy and to emissions from processes, in the vineyard and the distillery. These emissions are not all additional, as shown in the following examination. 6.2.5.2.1. Emissions of CO2 related to the use of energy on the site Strictly speaking, emissions from combustion do not include previous emissions from production of combustibles; however, they are given as a reminder. Notation convention: without previous, rounded up (calculated value) with previous, rounded up, in CO2e. – Combustion of diesel by winemaking machinery: destocking of fossil carbon
14,100 (14,081) [17,800] kg CO2
– Combustion of propane by handling machinery: destocking of fossil carbon
600 (594) [700] kg CO2
– Combustion of natural gas by the boiler room for heating the premises and control of fermentation: destocking of fossil carbon
42,500 (42,412) [50,500] kg CO2
6.2.5.2.2. Emissions of CO2 related to the processes Alcohol fermentation Under the action of yeast, grape glucose is transformed into ethanol (alcohol). A second fermentation, under the action of bacteria, occurs shortly afterwards and transforms the malic acid into lactic acid. These two types of fermentation release carbon dioxide. However, the carbon here is from the grapes, extracted by the vine from the atmosphere by photosynthesis. These emissions therefore do not cause an additional greenhouse effect. Their contribution is zero. Emanations of CO2 of chemical origin for an inert environment in the vats Carbon dioxide is introduced into the vats to replace the air and prevent oxidation of the wine. Opening of the vats liberates carbon dioxide into the atmosphere. The data specify that this gas is of chemical origin, which implies that it
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is new in the environment and that it contributes to global warming. Since the volumetric mass (at 15°C and atmospheric pressure) of carbon dioxide is 1.87 kg/m3, 400 m3 of leaked CO2 represents 748 kg CO2. In the leakage contribution, the emissions related to production of this gas must not be forgotten (excluded from the exercise, according to the question). 6.2.5.2.3. Emissions of CO2 related to waste Burial of vine shoots Part of the organic carbon is stored in the ground (but this carbon is not deduced from the balance) and part is mineralized in the form of CO2, which does not bring about an additional greenhouse effect since it corresponds to the quantity extracted from the atmosphere by the vine during photosynthesis. Fermentation of effluents in the wastewater works Agitation of the effluents creates aerobic conditions and consequently is favorable to the activity of microorganisms which release carbon dioxide. The carbon at play is in the short cycle and these emissions do not lead to an additional greenhouse effect. QUESTION.– What about excess effluents treated by natural evaporation? Aerobic fermentation of distilled composted dregs For the same reason, where the compost must be regularly aerated to avoid anaerobic fermentations which produce methane, composting of waste from vinification does not have a direct impact on the climate. QUESTION.– Why is the emissions factor for production of compost from dregs not then zero, including under the hypothesis that the emissions from winemaking are allocated to the wine, and the emissions from distillation are allocated to the alcohol? Emissions from combustion for distillation of dregs and sediments According to a lifecycle analysis, distillation emits 180 kg CO2e per metric ton of grape dregs [FÉD 12, p. 10]. Making the hypothesis that distillation of the sediment requires nearly the same quantity of energy, the total emissions from distillation of the by-products of the activity represent: Ed = (12 + 2) × 180 = 2,520 kg CO2e
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Climatic Impact of Activities
6.2.5.3. Taking into account the emissions from treatment of residues of winemaking 1) The emissions from carbon dioxide generated by the treatment of by-products of winemaking are detailed in Figure 6.7.
Figure 6.7. Emissions generated by treatment and repurposing of the residues of winemaking (M, x and m are respectively the quantities of residues, alcohol and compost that are bought by the wine-grower)
2) The dregs and sediment are sent to the Marly distillery, which uses natural gas to heat the distillation columns. The manager of the vineyard does not want the emissions related to the distillation of his own production waste to be included in his balance because the distiller repurposes the dregs and sediment with sale of the alcohol to the State and sale of compost to the wine-growers, and in that case, the emissions are the full responsibility of Marly. Following the accounting reasoning described in the methodology chapter, these emissions can be attributed in full to the vineyard, which in addition has the means available to reduce them by repurposing its waste directly on the property (however by means of payment of a tax). These same emissions are also counted in the context of a balance for the distillery, where the double-accounting is not important, so long as the balances of each are not combined. The financial logic invoked by the manager of the vineyard is too disconnected from physical reality of the emissions to be admissible. 3) The dregs and sediments are distilled and the solid residues are composted by Marly. The vineyard operator buys the compost from them as a top-up organic soil enricher. The cycle of production of the dregs compost extends for more than one year. It is necessary for the flows to be correctly mapped out according to the sequences of the process. Let us consider the general case where part of the emissions from the vineyard activity would be allocated to the repurposable by-products (dregs and sediment) in the proportion α (i.e. (1- α) being attributed to the wine): – with M the quantity of dregs and sediment sent for distillation and m the quantity of compost bought and reimported: β = m / M; – with Ev the emissions from vine-growing and winemaking, and Ed the emissions from distillation and composting for the quantity M;
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– emissions from production of residues of winemaking: α Ev; – emissions of the flows of reimported compost: β (α Ev + Ed). A balance is a “photograph” of the flows over a given period of time. For the balance for an isolated year, the component α Ev is taken into account twice, once under waste and once under inputs, but it does not affect the same material and is therefore not redundant. This does not pose any more problems since the compost was bought outside this circuit. On the other hand, if the annual balances are combined or if an extrapolation is made over several years, the component α Ev would be supernumerary and it would be necessary to check that it only contributes to the total emissions once each year.
Figure 6.8. Sequence of emitting processes related to the flows of winemaking by-products. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
6.2.5.4. Recommendations for reduction of emissions from the activity A technical guide provided by the Institut Français de Vin [INS 11, p. 24 and 25] to establish an emission balance of greenhouse gas proposes specific emissions factors and a table of recommendations to reduce the climate impact of winemaking activity. 6.3. Case study 3: factory for production of animal feed 6.3.1. Description of the activity The factory produces about 105,000 metric tons of feed each year, destined for local poultry (75% of production) and cattle (25%) industries.
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Climatic Impact of Activities
Production is determined by requests from the clients, and there are no stocks of finished products. Three production lines ensure manufacturing of flours, granulates and crumbs. About 30 raw materials are delivered loose or in bags: cereals, soybean meal, oils, mineral powders and various additives. They are ground and mixed to obtain flours, granulates and crumbs. Supply of corn represents 50% of the raw agricultural materials and comes from two main categories: – the corn harvested by regional farm operations and bought in raw format, with 30% humidity. This corn is dried by the factory using the heat produced from combustion of the natural gas, to reduce its humidity to 15% in order to ensure the grain stores well; – the various by-products of corn (flour, fragments, gluten, etc.), bought from suppliers who have themselves dried and transformed the raw corn. The soybean meal is imported from Brazil and represents 20% of raw agricultural materials (unknown emissions factor). The energies used by the factory are electricity for the machinery, natural gas for corn drying and for production of water vapor, which serves as a binder in the fabrication of granulates, and cleaning. The supply in raw agricultural materials is provided by transporters and is carried out by semi-trailer trucks with a GVWR of 44 metric tons. Transport of feed to farms is carried out, on request, by trucks with a GVWR of 20 metric tons, using the factory fleet. The main waste is packaging (card, wood, plastic), recycled materials, production offcuts and sweepings, which are composted.
Figure 6.9. Synoptic diagram of the production processes. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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6.3.2. Challenge in this exercise For this case, an exhaustive calculation of the emissions is not necessary in order for the balance to be established. The proposed workings are as follows: – calculation of the emissions related to corn drying and to the use and end of life of the products; – estimation of the emissions factor of soybean meal imported from Brazil; – allocation of emissions to the poultry and cattle industries; emissions factors for feed at various stages of the lifecycle; – recommended actions to reduce the emissions related to the three dominant groups (the emission profile related to the factory activity will be provided). 6.3.3. Specific activity data Energy Natural gas for corn drying and production of water vapor EF natural gas (combustion + previous) (EFng)
1,977 MWh LCV 0.243 kgCO2e/kWh LCV
Agricultural inputs (DM means “dry material”) Raw corn bought at 30% humidity Tonnage after reduction of the humidity rate to 15% (M0.15)
42,291 t
Drying energy (e) [ADE 11]
3.5 to 4 MJ/kg water
Emissions factor for corn grains at 30% humidity (EFC0.30)
530 kg CO2/t MS
Corn by-products (bought ready for use at 15% humidity) (BPC0.15)
3,626 t
Transport for supplies of raw agricultural materials Tractor and semi-trailer
8,436,789 t.km
Delivery of feed to farm clients Diesel consumed (container truck, 20 t)
460,788 liters
Proportion of journeys when empty
15%
Rate of loading compared to the payload capacity
80%
Use and end of life of feed Tonnage of feed produced for the poultry industry (MFv)
78,750 t (75%)
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Climatic Impact of Activities
Weight of a standard chicken (MUv)
2.2 kg
Conversion index of the feed into poultry (CIv) (weight of feed, in kg, to produce 1 kg of chicken)
1.84
Digestion and excretions from poultry (EvCH )
0.800 kg CH4/
4
poultry.yr Digestion and excretions from poultry (EvN O) 2
0.005 kg N2O/ poultry.yr
GWPCH 4
28
GWPN O 2
265
Lifetime of standard chicken (LTv)
35 days
Yield in poultry carcasses with respect to the live weight (ρv)
66%
Tonnage of feed produced for the cattle industry (MFb)
26,250 t (25%)
Ration of concentrated feed (RCF)
4 kg/cow.day
Digestion and excretions of the cattle (EbCH )
141.9 kg CH4/cow.yr
Digestion and excretions of the cattle (EbN O) 2
3.32 kg N2O/cow.yr
Rate of concentrated feed provided by the factory in the daily ration for cattle (τ)
25%
Conversion age for milk cows (LTb)
7 years
Weight of a converted cow (Mb)
750 kg
Yield in cow carcasses with respect to live weight (ρb)
55%
4
6.3.4. Answer to case study 3: factory for production of animal feed 6.3.4.1. Calculation of emissions 6.3.4.1.1. Emissions due to corn production and drying Supply of corn comes from two main categories: – corn harvested by regional farming operations and bought raw, at 30% humidity, then dried in the factory using heat produced by combustion of natural gas, to decrease its humidity rate to 15%; – various by-products of corn (flour, fragments, gluten, etc.), bought from suppliers who have themselves dried and transformed the raw corn.
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If x is the humidity rate and MX is the tonnage of the moist corn, the tonnage of dry material MDM is: MDM = (1 - x) MX Case of raw corn The raw quantity is bought in at 30% humidity, but the tonnage is given in quantity of dried corn at 15%. In addition, the emissions factor is related to the dry material (0% humidity): MDM1 = M0.15 (1 - 0.15) MDM1 = 42,291 (1 - 0.15) = 35,947 t The factory is supplied with corn at 30% humidity, which is then dried to 15% using natural gas. Since the emissions from combustion of natural gas are already counted in the “energy” group, and to avoid counting them twice, it is a good idea to use the emissions factor before drying, that is, EFM0.30 = 530 kg CO2e/t DM, applied to the tonnage of dried material calculated above2. The emissions related to corn production, excluding drying, are: EC = 35,947 × 530 / 1,000 EC = 19,000 (19,052) t CO2e As a reminder, with the production of water vapor, drying the corn releases part of the energy released by the combustion of natural gas which, in total, emits: EE = (1,977 × 1,000) × 0.243 / 1,000 = 480 t CO2e
2 This value of 530 ± 30 % kg CO2/t DM comes from a study by the author, communicated to ADEME in 2006. The Base Carbone® [ADE 18b] gives 338 kg CO2/t for corn at 28% humidity, which, normalized to the weight of dry material, represents 469 kg CO2/t DM, a value that is compatible with the value used here taking into account the uncertainties of 30%.
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Climatic Impact of Activities
Case of by-products of corn (BPC) The residual humidity level of all the corn by-products is 15%: MDM2 = BPC0.15 (1 - 0.15) MDM2 = 3,626 (1 - 0.15) = 3.082 t DM In this case, and since the factory has not used energy to dry the corn because this had been done previously by suppliers, the emissions factor to be applied to the weight of dry material must take into account the drying energy. 6.3.4.1.2. Calculation of the emissions factor for production of corn by-products The emissions factor for corn in grain format, before drying and transformation to obtain by-products of corn is: EFC0.30 = 530 kg CO2e/t DM. For the by-products, the calculation would also be based on the metric tonnage of dry material. Weight of by-products with 15% humidity entering the factory and corresponding to a unit weight (UDM) of 1 metric ton of dry material: BPCU0.15 = UDM / (1 - 0.15) = 1 / (1 - 0.15) = 1,176 t Weight of corn at 30% humidity arriving at suppliers of by-products and corresponding to 1 metric ton of dry material: BPCU0.30 = UDM / (1 - 0.30) = 1 / (1 - 0.30) = 1,429 t Weight of evaporated water for 1 metric ton of dry material: Mwater = BPCU0.30 – BPCU0.15 = 1,429 - 1,176 = 0.253 t The quantity of energy (e) for extraction of a kilogram of water is 3.5 à 4 MJ/kg, that is, 3.5 to 4 GJ/t [ADE 11]. We select the higher value, that is, e = 4 GJ/t. Quantity of energy ξs for corn drying, of 30 to 15% humidity, for a metric ton of dry material: ξs = Mwater e = 0.253 × 4 = 1,012 GJ/t DM, rounded to 1 GJ/t DM
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1 kWh LCV = 3.6 MJ ξs = 281 kWh/t DM The source of energy is natural gas, of which the emissions factor is EFng = 0.243 kg CO2e/kWh LCV. Emissions (ES) corresponding to corn drying represent a metric ton of dried material: ES = ξs EFng = 281 × 0.243 = 68.3 kg CO2e/t DM The emissions factor for dried corn (15% humidity): EFBPC0.15 = EFC0.30 + ES EFBPC0.15 = 530 + 68 = 598 kg CO2e/t DM; rounded to 600 kg CO2e/t DM A fixed increase must then be applied to this emissions factor, for example, of 20%, to take into account the emissions due to previous transformation processes applied to the corn. Resultant emissions factor: EFBPC0.15 = 720 kg CO2e/t DM (uncertainty estimated to be ±50%) The emissions related to production of corn derivatives are: EBPC = PDM2 EFBPC0.15 = 3.082 × 720 / 1,000 = 2,219 t CO2e EBPC = 2,200 (2,219) t CO2e 6.3.4.1.3. Emissions related to the use and end of life of products The use and end of life of a type of feed are amalgamated into the ingestion, digestion and fermentation processes of excretions. Case of poultry MFv: tonnage of feed destined for poultry. CIv: conversation index (weight of feed to produce 1 kg of poultry). Mv: tonnage of poultry fed with MFv.
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MUv: average weight of a fowl. Nv: number of fowls corresponding to the weight Mv. EvCH4: quantity of methane emitted per fowl and per year. EvN2O: quantity of nitrous oxide emitted per fowl and per year. EFdv: emissions factor related to digestion and excretions. LTv: lifetime of poultry. Ev: emissions related to digestion and excretions of Nv fowls. APPLICATION.– MFv = 75% of 105,000 t CIv = 1.84 MUv = 2.2 kg EvCH4 = 0.8 kg CH4/fowl.yr EvN2O = 0.005 kg N2O/fowl.yr Mv = MFv / CIv Mv = 0.75 × 105,000 / 1.84 = 42,799 t Nv = Mp / MUv Nv = 42,799 × 1,000 / 2.2 = 19,454,051 poultry Emissions factor related to digestion and excretions from poultry: EFdv = GWPCH4 EvCH4 + GWPN2O EvN2O EFdv = 28 × 0.800 + 265 × 0.005 = 23.73 kg CO2e/fowl.yr
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The emissions factors related to each of the gases are given for one year, but the poultry only live for 35 days. EFdv = EFdv . LTv / 365 EFdv = 23.73 × 35/365 = 2.275 kg CO2e/fowl Annual emissions related to digestion and excretions from poultry: Ev = Nv . EFdv Ev = 19,454,051 × 2.275 / 1,000 Ev = 44,300 (44,258) t CO2e Case of cattle MFb: tonnage of concentrated feed destined for cattle. MUb: average weight of a cow. Nb: number of cattle. EbCH4: quantity of methane emitted per cow and per year. EbN2O: quantity of nitrous oxide emitted per cow and per year. EFdb: emissions factor relating to digestion and cattle excretions. Eb: emissions relating to digestion and excretions of Nb cattle. Ebcf: proportion of emissions related to digestion and excretions of Nb cattle due to concentrated feed. RCF: daily consumption of concentrated feed. RTF: total quantity ingested on a daily basis. According to the question: RCF / RTF = τ = 25%. APPLICATION.– Case of milk cows. MFb = 25% of 105,000 t
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RCF = 4 kg/head.day RCF / RTF = 0.25 EbCH4 = 141.9 kg CH4/milk cow.yr EbN2O = 3.32 kg N2O/milk cow.yr Number of cattle that consume concentrated feed: Nb = MFb / (365 RCF) Nb = 0.25 × 105,000 × 1,000 / (365 × 4) = 17,979 heads Emissions factor related to digestion and excretions from cattle: EFdb = GWPCH4 EbCH4 + GWPN2O EbN2O EFdb = 28 × 141.9 + 265 × 3.32 = 4,853 kg CO2e/head.yr Eb = Nb EFdb Eb = 17,979 × 4,853 / 1,000 = 87,252 t CO2e The contribution to emissions from use and end of life of concentrated feed (Ebcf) provided by the factory is counted in proportion with the weight of feed in the ration: Ebcf = τ Eb Ebcf = 0.25 × 87,252 Ebcf = 21,800 (21,813) t CO2e 6.3.4.2. Emission profile for the activity The balance has given the following emission profile (t CO2e). The missing groups (direct emissions not due to energy, emissions related to movement and treatment of wastes) are comparatively very low and do not appear at the scale of the diagram.
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Figure 6.10. Dominant groups of direct and indirect greenhouse gas emissions, related to the activity of the animal feed production factory
What can you propose for reduction of the climate footprint of the factory? 6.3.4.3. Allocation of emissions for each sector Recap of the emissions for the main groups (t CO2e). Total tonnage of feed produced: 105,000 t/yr. Total
Poultry
Cattle
Use and end of life of feed
66,071
44,258
21,813
Agricultural inputs
44,084
Transport of merchandise
2,355
- of which previous
574
- of which later
1,781
Energy
955
Carbon amortization
492
Movement of people
98
Production and end of life of feed packaging
80
Company waste
29
Direct emissions except for energy
(negligible)
General total
115,000 (114,164) ± 27% t CO2e
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Climatic Impact of Activities
The emissions factor of the feed represents unit emissions, on departure from the factory (except for delivery transport, use and end of life of feed): EF = 114,164 - (66,071 + 1,781) / 105,000 kg CO2e/t EF = 441 kg CO2e/t Only the emissions due to use and end of life of the feed are specific. The other emissions can be allocated to each sector in proportion with the quantities of feed, that is, 75% for poultry and 25% for cattle. Poultry
Cattle
Use and end of life of feed
44,258
21,813
Agricultural inputs
33,063
11,021
Transport of merchandise
1,766
589
Energy
716
239
Carbon amortization of fixed assets
369
123
Movement of people
74
25
Production and end of life of feed packaging
60
20
Company waste
22
7
Total
80,328
33,837
Tonnage of feed (t)
78,750
26,250
Global unit emissions (kg CO2e/t)
1,020
1,289
Of which use and end of life (kg CO2e/t)
562
831
t CO2e
Box 6.1. Emissions factor in the life cycle
6.3.4.4. Contribution of industrial feed to the emissions factor of carcasses 6.3.4.4.1. Case of poultry Reference tonnage of carcasses: Tcv = 1 t. Yield in carcasses: ρv = 0.66. Tonnage of live poultry: Tvv = Tcv / ρv = 1.52 t.
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Conversion index (weight of feed to produce 1 kg of poultry): CIv = 1.84. Weight of feed required for a metric ton of carcass: Mfv = Tvv . CIv = 2.80 t. Unit global emissions calculated above for poultry: EVug = 1,020 kg CO2e per metric ton of feed. Emissions factor of a metric ton of poultry carcasses: EFVc = Mfv . EVug. Contribution of feed produced by the factory to the emissions factor for carcasses: EFVc = 2,900 (2,856) ± 30% kg CO2e/t carcass 6.3.4.4.2. Case of cattle (converted cows) Reference tonnage of carcasses: Tcb = 1 t. Yield in carcasses: ρb = 0.55. Tonnage of live cattle: Tbv = Tcb / ρb = 1.82 t. The age reached by a converted cow weighing 750 kg (Mb) is 7 years (LTb), a time period during which it ingests 4 kg per day (pa) of feed provided by the factory and which constitutes a quarter of its feed ration (the approximation is made of a constant quantity of industrial feed ingested over the entire lifetime of the cow, supposing that the increase to milking and final fattening compensates the smaller quantity ingested by the young animal). Weight of feed required (Mfb) to produce a metric ton of carcasses: Mfb = (Tbv / Mb) LTb (pa × 365) = 24.8 t / t carcass. Global unit emissions calculated above for cattle: EBug = 1,289 kg CO2e per metric ton of feed. Unit emissions of cow carcasses (contribution only from industrial feed): EFBc = Mfb . EBug. Contribution of the feed produced by the factory to the emissions factor of carcasses: EFBc = 32,000 (31,967) ± 30% kg CO2e/t carcass
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Climatic Impact of Activities
6.3.4.4.3. Coherence test The Base Carbone® [ADE 18b] provides the following emissions factors: – chicken for meat (average): 2,140 kg CO2e/t live chicken; – converted cow: 16,860 kg CO2e/t live cow. Normalized to the weight of carcasses, these figures become: – chicken for meat (average): 2,140 / 0.66 = 3,242 kg CO2e/t; – converted cow: 16,860 / 0.55 = 30,654 kg CO2e/t. Our calculations give: EFVc = 2,856 kg CO2e/t and EFBc = 31,967 kg CO2e/t for poultry and converted cows respectively. Taking into account the uncertainty, of the order of 30%, the agreement is excellent, particularly because the scope considered is not exactly the same: focused on the production of feed in our case, focused on livestock raising for the Base Carbone®. 6.3.4.5. Estimate of the emissions factor for soybean meal WARNING.– Calculation of this emissions factor is only given as an indication, to demonstrate the type of reasoning to be applied. It is in no instance a reference and must not be used as an approved emissions factor. The main sources of emissions related to the supply of soybean meal produced in Brazil are as follows: – soya cultivation: - production of fertilizers; - emanations of N2O related to the assimilation of nitrogen in soils; - production of phytosanitary products; - consumption of fuel by agricultural machinery; - carbon amortization of agricultural machinery; - contribution of the change in use of the soils to carbon destockage; – trituration of soybeans; – transport of soybean meal to the dispatching port.
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For this estimated calculation, various simplifying hypotheses are conceded, for example, emissions factors required by the calculations are generally applicable to France [ADE 18b], certain agronomical practices are also presumed similar, etc. 6.3.4.5.1. Production of fertilizers According to Horsch [HOR 06, p. 5], in Brazil, “to harvest 30 qx of soya, 80 kg of potash is required and 500 kg/ha of a mix 2/20/10 (N/P/K)”. Chemical nature
Quantity kg/ha
Emissions factor Unit emissions kg CO2e/t kg CO2e/ha
Nitrogen (N)
500 × 0.02
5,027
50.3
Phosphorus (P2O5)
500 × 0.20
467
46.7
Potassium (K2O)
500 × 0.10
470
23.5
Potassium (K2O)
80
451
36.1
Total
156.6
6.3.4.5.2. Emanations of N2O related to the assimilation of nitrogen in soils Quantity of nitrogen kg/ha
Emissions factor kg CO2e/kg N
Unit emissions kg CO2e/ha
500 × 0.02
5.57
55.7
6.3.4.5.3. Production of phytosanitary products Depending on the products and their associations, the quantity of active herbicide matter spread over the soya varies, but the order of magnitude is 1 kg/ha. Quantity of active matter kg/ha
Emissions factor kg CO2e/kg
Unit emissions kg CO2e/ha
1
9.15
9.2
6.3.4.5.4. Consumption of fuel by agricultural machinery The energy consumed by agricultural machinery is presumed equal to that observed in France for wheat crops, that is, about 106.74 liters of diesel per hectare [ADE 10b, p. 13]. Quantity of diesel l/ha
Emissions factor kg CO2e/l
Unit emissions kg CO2e/ha
107
3.17
339
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6.3.4.5.5. Carbon amortization of agricultural machinery The contribution of carbon amortization of agricultural machinery in France, for wheat growing, is 6.6 kg C/ha, in other words, 24 kg CO2e/ha [ADE 10b, p. 14]. 6.3.4.5.6. Summary of emissions from crops In other words, EFc is the emissions factor of soya cultivation. EFc = 156.6 + 55.7 + 9.2 + 339 + 24 = 584.5 EFc = 585 kg CO2e/ha 6.3.4.5.7. Contribution of deforestation to the increase in cultivated areas The case of the State of Mato Grosso is typical of deforestation for soya cultivation in Brazil: “In 1996, the Mato Grosso had the largest forested savanna reserve in Brazil with nearly 42 million hectares classed in the category of cerrados. But it has also become, since 1999, the top State producer of soya in the country and it has therefore begun to significantly exploit this reserve area” [BER 06, p. 5]. The destroyed carbon stocks (ground and vegetation) represent 187.5 t C/ha and 81.5 kg C/ha for the tropical forest and savanna respectively [POI 08, p. 73]. We presume that the increase in cultivable land has been to the detriment of the forested savanna (cerrado) and the tropical forest in equal proportions. Average destockage is therefore: Ed = (187.5 + 81.5) / 2 = 134.5 t C/ha in other words: Ed = 134.5 × 44 / 12 = 493.2 t CO2/ha This destockage is spread over 100 years: EFd = 493.2 × 1,000 / 100 = 4,932 kg CO2/ha.yr Soya is cultivated in rotation with corn: “In fact, the progress in corn yields leads to levels of production that are similar to summer harvests and this causes a soya-corn model to emerge with two harvests for the same campaign” [BER 04, p. 54]. Two corn/soya harvests in the same year necessitate an allocation of the emissions from deforestation, in equal proportion, of 50% for each crop.
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For soya, the resulting emissions factor is: EFdsoya = 4,932 × 0.50 EFdsoya = 2,466 kg CO2/ha.yr The area dedicated to cultivating soya in the Mato Grosso is 4.6 Mha [BER 04, p. 41]. The surface that has been cleared for this crop is 1.35 Mha [CAB 06, p. 25]. The soya from deforestation therefore represents 1.35/4.6 = 29.3% of production of the Mato Grosso. Taking account of carbon destockage due to reconversion of the use of soils, the emissions factor of the crop is therefore increased: EFc-dsoya = EFc + 0.293 EFdsoya = 585 + 0.293 × 2,466 EFc-dsoya = 1,308 kg CO2/ha The yield of soya crops in the Mato Grosso is 29.5 quintals per hectare [BER 06, p. 6]. The emissions factor for soya cultivation taking account of deforestation, normalized to a metric ton produced, is: EFc-dsoya = 1,308 / 2.95 EFc-dsoya = 443 kg CO2/t (including 245 kg CO2/t due to deforestation) 6.3.4.5.8. Transformation (trituration of soybeans) We suppose that transformation is carried out in the State of Mato Grosso, near sites of soya production. According to Battais et al. [BAT 06, p. 25], trituration of canola seeds requires energy expenditure of 347 kWh per metric ton of grain. We suppose the same order of magnitude for soya. According to the Base Carbone® [ADE 18b], the emissions factor of network electricity in Brazil is 0.0868 kg CO2e/kWh. The emissions factor of trituration of soya is of the order of: EFtri = 347 × 0.0868 = 30 kg CO2e/t 6.3.4.5.9. Allocation of emissions to by-products of trituration A metric ton of soya provides 180 kg of oil, 800 kg of meal and 20 kg of residue. The emissions from soya cultivation and trituration are allocated to the two by-products, oil and meal, in the proportionate quantities:
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EFto = (EFc-dsoya + EFtri) × 800 / (800 + 180) EFto = 386 kg CO2e/t 6.3.4.5.10. Transport of soybean meal to the dispatching port The transportation distances from the soya production areas in the Mato Grosso to the port of Paranaguá are of the order of 2,200 km. Exportation of 13 metric tons (Mt) of soya produced in this State consumes 270 kt of diesel, that is, 20.8 kg of diesel per metric ton of soya [BER 04, p. 200]. Since the emissions factor of diesel is 3.743 kg CO2e/kg (for France) [ADE 18b], transport emissions in South America are estimated to be 77.7 kg CO2e per metric ton of soya, rounded to 80 kg CO2e/t. The proportion attributed to the meal, in the proportion of tonnages of by-products, including residues in this case, is: EFtra = 80 × 800 / (800 + 180 + 20) EFtra = 64 kg CO2e/t 6.3.4.5.11. Emissions factor of Brazilian soybean meal (at time of dispatch from Brazil to France) EFmeal = 386 + 64 = 450 kg CO2e/t (uncertainty estimated at 50%) EFmeal = 450 ± 225 kg CO2e/t
Figure 6.11. Main contributions to greenhouse gas emissions from the production processes of soybeans in Brazil. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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6.3.4.6. Succinct recommendations 6.3.4.6.1. Emissions related to the use and end of life of feed Relying on the unit emissions for use and end of life normalized to a metric ton of feed, given in section 6.3.4.3, and on the calculations developed in section 6.3.4.4. (6.3.4.4.1 for chicken and 6.3.4.4.2 for cattle), calculation is made of the use and end-of-life emissions for feed normalized to a metric ton of carcasses. Case of poultry Emissions for use and end of life of the feed for a metric ton of poultry carcasses: EFVV = 562 × 2.80 = 1,574 kg CO2e/t carcasses Case of cattle (converted cows) Emissions for use and end of life of feed for a metric ton of cow carcasses: EFVB = 831 × 24.8 = 20,609 kg CO2e/t carcasses Summary Particularly vigilant efforts should target cattle farming, particularly due to enteric methane emissions. The production of concentrated animal feed for intensive agriculture constitutes an in-depth technical system, with a narrow margin of maneuver in the formulation of feed, and significant constraints from an economics point of view. Nevertheless, it would be useful to take certain studies into account to try to refine the formulation of feed for cattle. Thus, Martin et al. have summarized various publications concerning the reduction of enteric methane emissions of ruminants: “Concentrates rich in starch (barley, wheat, corn) have a greater effect of depressing methanogenesis than concentrates rich in digestible walls (beetroot pulp). In milk cows, replacement of beetroot pulp (70% of the ration) by barley has caused a reduction of 34% of the energy losses in the form of methane (Beever et al., 1989)” [MAR 06, p. 8]. Lipids (canola, flax, sunflower) reduce enteric methanogenesis by 30 to 50% (a constitution of 6% lipids with flax seeds reduces methane emissions from a milk cow by 27 to 37%) [VAN 10, p. 36].
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A reduction in proteins contributes to limiting the nitrogen content of excretions and thus to reducing subsequent emissions of nitrous oxide (N2O). An experimentation with the introduction of plant extracts that lead to a reduction of enteric methanogenesis in the feed concentrates could be carried out. According to Martin et al.: “Studies of plant extracts have been carried out essentially in vitro. Thus, extracts of garlic, pepper, yucca, cinnamon (Cardozo et al., 2004), rhubarb and alder buckthorn (Garcia-Gonzalez et al., 2006), alfalfa serum obtained by pressing fresh alfalfa and eliminating proteins by flocculation (Jouany et al., 2005) have resulted in a reduction of methanogenesis” [MAR 06]. For both sectors, actions can contribute to a reduction in the emissions from fermentation of excretions. The factory can thus make the client operations aware of the development of methanization with energy repurposing, to reduce the emissions of methane related to storage of liquid and solid manure. 6.3.4.6.2. Production of agricultural inputs Activity of the factory is sensitive to changes in regulatory, environmental and energy contexts. The actions that could be encouraged in agricultural raw materials suppliers that the production depends on will be examined. “Low-carbon” cultural practices Margins of maneuver exist in producer–suppliers to reduce the climate impact of crops. Sustainable fertilization, crop rotation, simplified cultivation techniques, agroforestry, etc. are all options that need to be encouraged and of which at least awareness needs to be raised. The very future of agricultural operations can depend on this. The elements below succinctly summarize the options for “low-carbon” agriculture. – Simplified cultivation techniques: simplified cultivation techniques (SCT) can lead to a 55% reduction in mechanized working time. For a corn-growing operation studied by the author, the calculation has demonstrated that the SCT could be translated as a reduction of 7% in the global emissions from exploitation. – Crop rotation with legumes: lifecycle analyses have shown that a crop rotation including peas reduces greenhouse gas emission by 8% [PRO n.d.]. – Partial substitution of synthetic nitrogen by organic nitrogen: production of nitrous fertilizers and their transformation in soils by microorganisms with production of nitrous oxide, a powerful greenhouse gas, represents the main source
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of emissions of corn cultivation. A good improvement option is partial substitution by compost, with lower energy requirements for production and the possibility of reducing doses, insofar as the nitrogen is better fixed in place. – Intermediate crops: rapid-growth crops, between the main periods of cultivation, reduce the phenomenon of carbon being washed and carried away and allow the soil to be enriched with nitrogen in the case of legumes (field beans, clover, vetch, etc.). – Agroforestry: agroforestry consists of cultivating, on the same plots, trees and annual plants. According to INRA [DUP 06], productivity of agroforestry plots exceeds the productivity reached in separate cultures by 20–50%. The additional storage of carbon in the soil and the trees represents on average 3.7 t CO2/ha.yr [PEL 13, p. 49]. Production of plant oil fuel There are now production line tractors designed to operate with plant oil, and the French agricultural orientation law dated January 5, 2006 stipulates that this type of fuel is authorized for agriculturalists who produce it themselves. Reduction on the part of Brazilian soya A significant part of soya cultivation areas in Brazil has originated from the destruction of primary biomes, which is a curse for both biodiversity and the climate. This type of supply is incompatible with the policy of sustainable development that is advocated. The economical margin for maneuver is perhaps too low for priority to be given to French soya at the moment, which is not competitive in comparison with Brazilian soya, but local production of soya will become without doubt pertinent in the medium term. In the meantime, reduction of the proportion of soya in the formulation would be desirable. Field beans, lupins and peas can in principle replace soya in contributing proteins, but the appetence and anti-nutritional factors for animals can be hindrances. NOTA BENE.– “The WWF has deployed an in-the-field team in partnership with the Groupe Bel, that aims to point soya producers in the region of Mato Grosso (Brazil) in the direction of responsible production and to access RTRS certification (Round table for responsible soya), since the transition towards production methods that are more respectful towards the environment is essential for conservation of ecosystems and species in the region” [WWF 18]. Additional detailed information about the possible actions for cultural practices and livestock practices are given in the scientific literature (e.g. Pellerin et al. [PEL 08], Vandaele [VAN 10], Pommier [POM 13]).
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6.3.4.6.3. Transport of feed to clients’ farms Agricultural inputs arrive on full trucks, with high tonnage, whereas feed is delivered to farms on smaller trucks and only on request, which often uses only part of the payload capacity. Delivery of feed to farms in the region is therefore the main source of transport-related emissions (75%). It is possible to aim for a reduction in fuel consumption by trucks, thanks to the use of embedded IT systems to monitor and track driving, and GPS to localize depots and optimize journeys. The drivers could be trained in economical driving techniques. It is noted that deliveries are carried out with trucks whose GVWR is 20 t, which is a payload capacity of about 12 metric tons (see Table 4.1). A more systematic use of the semi-trailer, whose payload capacity is 25 metric tons, would lead to lower emissions. A possible solution would be to tend towards delivery on full trucks to limit empty journeys, by optimizing organization of rounds. To reach this objective, the factory could encourage buildings to be closer together on the farms and operation with single rows of poultry on each unit. Calculation of the expected reductions – Current situation. Currently, 20 metric ton GVWR container trucks travel empty for 15% of the journey, and when loaded, they transport 80% of the payload capacity (production is 105,000 metric tons, and the payload capacity of the container trucks is 11.62 t). NOTATIONS.– P: annual production. Dp: cumulative distance traveled for all client deliveries. dp: average distance traveled by a container truck for a delivery. αp: percentage of the distance traveled empty by the container trucks. Cp: loaded payload capacity of container trucks. βp: percentage of the loaded payload capacity for container trucks.
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Np: number of container trucks (or rotations) required for deliveries. Ep: emissions generated by the fleet of container trucks. According to the VKm method presented in section 4.4.1.3.1: EFvkm = β (1 - α) (EFC - EFV) + EFV + EFF The question stipulates that the fleet of container trucks belongs to the factory. Since carbon amortization of the trucks is counted separately, in order to avoid counting it twice, the emissions factor for manufacturing is not taken into account at this stage (the index “p” is added to refer to the container trucks). EFvkm = βp (1 - αp) (EFCp - EFVp) + EFVp The total emissions are: Ep = EFvkm . Dp Ep = Dp [βp (1 - αp) (EFCp - EFVp) + EFVp]
[6.4]
Calculation of the cumulative distance traveled by the container trucks: Dp = dp Np Np = P / βp Cp Dp = dp P / βp Cp By substituting into [6.4], it becomes: Ep = (dp P / βp Cp) [βp (1 - αp) (EFCp - EFVp) + EFVp] – Prospective situation with fleet of tractors/semi-trailers. In a scenario with semi-trailers, supposing 21% of the journey when empty and 100% of the payload capacity when loaded, the same calculation would lead to the following expression (index s for “semi-trailer” replaces the index p for container trucks): Es = (ds P / βs Cs) [βs (1 - αs) (EFCs - EFVs) + EFVs]
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It follows that: Es / E p = (ds Cp / dp Cs) [(1 - αs) (EFCs - EFVs) + EFVs / βs] / [(1 - αp) (EFCp - EFVp) + EFVp / βp] CASE 1.– The hypothesis (H1) is made that the length of a rotation will not change, despite the greater quantity loaded with a semi-trailer, due to the increase in operational capacities: ds = dp hence: [Es / Ep]H1 = (Cp / Cs) [(1 - αs) (EFCs - EFVs) + EFVs / βs] / [(1 - αp) (EFCp - EFVp) + EFVp / βp] CASE 2.– The hypothesis (H2) is made that the extension of the rotations is proportional to the increase in capacity, so: ds / dp = Cs / Cp [Es / Ep]H2 = [(1- αs) (EFCs - EFVs) + EFVs / βs] / [(1- αp) (EFCp - EFVp) + EFVp / βp] According to the question and the data: Cp = 11.62 t αp = 15% βp = 80% According to the prospective hypotheses: Cs = 25 t αs = 21% βs = 100%
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According to Table 4.1: EFcp = 1.250 kg CO2e/vehicle.km EFvp = 0.869 kg CO2e/vehicle.km EFcs = 1.311 kg CO2e/vehicle.km EFvs = 0.911 kg CO2e/vehicle.km which gives: Hypothesis H1: [Es / Ep]H1 = 0.40 (60% of reduction of emissions) Hypothesis H2: [Es / Ep]H2 = 0.87 (13% of reduction of emissions) In both cases, the emissions due to later transport are significantly reduced as the size of the trucks increases.
Conclusion
By establishing a balance with a broad investigation spectrum, an inventory can be set up of the sources of emissions related to the activity of an organization, with the guarantee that important direct or indirect emissions will not be forgotten. My experience has shown me that preconceived ideas about dominant sources of emissions are very widespread, with these being generally attributed to the transport of merchandise and the movement of people, and that they are often not valid. Thus, certain emissions resulting from chemical processes, anaerobic fermentation, gas leaks, or related to product end-of-life, go relatively unnoticed, but can, in fact, be considerably larger. The advantage of a balance is also the possibility to place the quantitative importance of emissions into hierarchical order, which allows targeted actions with a high reduction potential to be conceived, even though, on the other hand, the calculated uncertainty is high. Establishment of a balance requires serious methodological rigor to apply correct reasoning, to avoid forgetting important aspects, to check coherence and pertinence of data, to avoid getting caught up in unnecessary calculations, to guarantee the traceability of reasoning and calculations and to operate with full transparency concerning hypotheses and approximations. The study requires collaboration between many people to provide data and co-construct an action plan: enthusiasm and teaching ability are essential to effectively encourage others to follow an ethical pathway. The strategy that needs to be developed in an organization to set off an ambitious “low carbon” project would have something to gain from taking inspiration from acting/thinking in a complex manner, which can provide advice about designing a trajectory for change, fitting contexts together, then locally “disturbing” the system to encourage the expected pathway to be followed, and lastly to leave it to evolve without trying in any way to master or to control the transformation process [ROS 18].
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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Producing a greenhouse gas emission balance is intellectually stimulating, because the exercise is a real investigation into an activity where an expert’s route is marked out by the resolution of various problems. Routine is not the prerogative of greenhouse gas emission balances; instead this is the guarantee of discovering a system in its complexity, which requires wide-reaching culture covering many disciplines, and depends on many unknowns and on participation from third parties. Producing a greenhouse gas emission balance is also and above all stimulating due to its purpose, which is to instigate actions that will lead to a reduction of the impact of the activity of an organization on the climate. A carbon dashboard is an essential aid to strategic and operational decision-making, at the service of organizations which seek to develop their environmental responsibility, to reduce their dependence on oil and their economic vulnerability to the increase in price of this resource. Lastly, through the contribution it makes to attenuating global warming, the approach serves the general interest and we can also justifiably expect to see a surge in social cohesion and economic benefits.
Appendices
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
Appendix 1 For a Physical Economy1
“Natural riches are inexhaustible because if this were not the case, we would not be able to obtain them freely. Since they can be neither multiplied nor exhausted, they do not come under economic sciences”. Jean-Baptiste Say French economist (1767–1832) A1.1. Foresight of a physical economy On a finite planet, the management of resources should maximize the service provided per unit quantities of resources. From the point of view of energy, the ratio of useful outgoing flow to primary incoming flow is the yield. This measure should be a primary indicator in the direction taken by the economy. The law of variation of the power as a function of the energy yield goes through a maximum for a yield of 0.5. The statistical data for France concerning primary and final energies since 1973 verify this law. As the decades go by, the power increases regularly, however, by a less and less significant amount, whereas the yield decreases. The power can be expressed as a function of the apparent productivity of work and of the final energy intensity. As a result, an energy policy that proposes an inversion of the current trend, by prioritizing performance of the yield, would
1 Version 8.0 dated 2nd September 2015 (based on version 1.0 dated 19th March 2013, filed on 10th June 2013, with Copyright France under the number NF2W2D6).
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set up a reduction of the global energy power, in other words a reduction in productivity. Reinterpretation of the economy in the light of a physical point of view may legitimize certain degrowth scenarios. A1.2. Economy and energy Energy is the fundamental reality which underlies all transformations, all activity. Living systems, anthropological systems and, in particular, economic activity can therefore be examined from the point of view of thermodynamics [ROD 12]. One of the principal pioneers of the physical approach to the economy, Nicholas Georgescu-Roegen [ROE 06], has soundly criticized the neoclassical economy by astutely invoking the second principle of thermodynamics, which stipulates that during a transformation, useful energy deteriorates and its availability reduces. True energy processes are therefore not reversible; yields inevitably decrease, etc. However, even regarding the primary principle of thermodynamics, there are major learning opportunities that have not yet been integrated into the economy. National economies refer to the gross domestic product to evaluate their performance. This indicator represents the sum of the added values, in other words the counterpart of the energy contributed all along the activity chains. The GDP therefore expresses an annual flow. The priority objective is an increase in this flow. However, a flow presumes a difference in potential or, expressed in a more prosaic fashion, “reservoirs” at each end of the flow. At previous stages of the chain, these reservoirs are sources of energies, raw materials and biomass, and at later stages, they are humans and biomes that receive the products, and wastes from the activity. The previous reservoirs become empty when the exploited resources are not renewable or, for renewable resources, when the rate of sampling exceeds the rate of renewal. The reservoirs in later stages fill up when the flow of waste is greater than the resorption capacity of the materials by natural environments. Thus, oil becomes rarer in the Earth’s crust and the carbon dioxide produced by its combustion accumulates in the atmosphere. The neoclassical economy does not integrate, in a physical sense, the capacity nor the status of the reservoirs in its approaches. Supply and demand, which calibrate prices, are not correlated with the potential of the resources, but to their instantaneous flow rate, which does not allow long-term evolution to be anticipated. The course set by the economy is too disconnected from physical contingencies, and pursuit of growth of the worldwide GDP leads at best to a dead end. Paradoxically,
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the desire to free ourselves from nature has chained us to it, due to the dependence on resources and un-controlled pollution. In the same way as nature and from an ethical point of view, humans themselves are not at the center of economic thinking, whose priority is efficient allocation of resources: “They aim [the reactions of economists] to maintain conventional economic analysis of the financial system in the context of a thinking apparatus that is highly abstract and more and more disconnected from the empirical analysis of social and human behaviors” [DED 13]. The abundance, facility of extraction and use of fossil energies is behind (at least up until the present day) the exponential development of production and consumption, allowing belief in the inexhaustible nature of resources and an infinity that rational accounting therefore has no need to consider. Yet, it has definitely been shown that physical flows of energy are in fact a major deciding factor in economics for evolution of the GDP [JAN 12]. In an economy that sees itself as frugal and patrimonial, one suitable criterion to consider would be the notion of energy yield and the priority objective would be to maximize this yield, meaning to maximize production and services with a minimum of invested energy. National and international accounting practices obviously take an interest in energy, but not from this preferable physical point of view. It is symptomatic not to see included in national statistics, both for France and, for example, for the International Energy Agency, the tables of values showing the overall energy yield of economies. However, the energy intensity (see Figure A1.1 for France), in other words the quantity of energy dissipated per monetary unit of the GDP, is well-documented. However, the reference to the flow unit of a GDP euro does not restitute performance related to the previous and subsequent potentials of the economic system2. As an example, in its Green Paper on the climate strategy for 2030, the European Union is always questioning whether the consumption of energy normalized to the GDP would not be a better indicator3. In the case of France, it is maintained that “today, in France, a third of a barrel of oil is required to produce one thousand euros of GDP, whereas in 1973 three times more was required to produce the same effective value” [ART 10], although the consumption of primary energy
2 The energy equation expressed in dimensions is ML2T -2. The GDP expresses an annual flow of money, which has a counterpart in the material flow, with the dimension of a flow rate MT -1. The dimension of the ratio that expresses the energy intensity is L2T -1, which is kinetic viscosity. 3 “It will also be necessary to consider if the metric for such a target should continue to be absolute energy consumption levels or whether a relative target related to energy intensity would be more appropriate (e.g. energy consumption relative to GDP or gross value added)” [COM 13].
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and final energy is increasing in absolute value (albeit with a downturn since 2008), and in value per inhabitant, and despite a sharp increasing trend of the country’s energy bill [SER 15]. In an article on energy transition [BEL 13], the IDDRI (a French think tank, the Institute for Sustainable Development and International Relations) confirms for its part that “in the absence of significant measures to substantially improve energy intensity, all growth of the GDP leads to an increase in energy consumption”, invoking the energy intensity as a pertinent indicator and considering the cause and effect relationship between the GDP and the consumption of energy in the orthodox and nevertheless debatable sense of the point of view of the physical economy. The ratio of the final energy intensity (iF = EF / GDP) to the primary energy intensity (iP = EP / GDP) automatically restitutes the overall energy intensity (EF / EP), but the economic analyses limit themselves to an interpretation of the energy intensity and not of the ratio of its two final/primary expressions.
Figure A1.1. Evolution of the final energy intensity in France between 1981 and 2011 (kWh/€)
A1.3. Final energy yield of national economies Statistical data from the International Energy Agency reveals an overall energy yield that has been regularly decreasing since at least 1970 (Figure A1.2). In 40 years, it has gone from 0.75 to 0.68.
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Figure A1.2. Worldwide energy yield (“world primary energy demand” over “world total final consumption”) of countries around the world, according to the International Energy Agency. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
COMMENT ON FIGURE A1.2.– For a given year, the values differ a little depending on the sources and one of the terms in the pair may be missing (primary energy EP; final energy EF). The graph shows, in red, the yields calculated when for a given source the two terms in the pair (EP; EF) are available and, in blue, the ratio of the annual average of primary energies available to the annual average of the final known energies (in this case, for certain sources, one of the terms in the pair (EP; EF) may be missing). In France, for several decades, the consumption of energy has been increasing, more sharply for primary energy than for final energy (Figure A1.3), which led to a reduction in the overall energy yield (Figure A1.4) from 0.69 to 0.58 between 1981 and 2011 (in 1973, the yield was 0.74). This decrease is greater than the worldwide average, which is seen in countries which have intensified their economy the most. For France, the data used come from the Pégase database, from the French Observation and Statistics Service (SOeS). A continuous series is available for the period 1981–2011. The energy data for 1973 come from statistics from INSEE (French National Institute for Statistical and Economic Studies) (the energy yield was 0.74 in that year)4. 4 The Pégase database does not provide figures for the period prior to 1981. The World Bank goes back to 1960, but only for the consumption of primary energy. The Eurostat database provides data for after 1990. INSEE does not provide a continuous annual series (only 1973 is available prior to 1990).
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From the point of view of the physical economy, the performance of France is in decline. The reduction in energy intensity, which is a priori something to be celebrated, only demonstrates that the growth rate of the GDP (around 70% over 30 years) is higher than the growth rate of the energy consumption (40% for the same period) and confirms that this indicator does not provide useful information for the patrimonial management of energy resources.
Figure A1.3. Evolution of the consumptions of primary energy (in red) and final energy (in green) in France between 1981 and 2011 (Mtoe). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
Figure A1.4. Apparent worldwide energy yield for France between 1981 and 2011
Appendix 1
A1.4. Energy yield and power: the case of France The final power is the final energy consumed per unit of time: Pf = Ef / t.
Figure A1.5. Final power (GW) of availability of energy for the French system
Figure A1.6. Theoretical curve of the variation of the power as a function of the yield of an energy system
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The average energy yield (η) in France is given by the ratio of the final energy consumed to the primary energy provided previously: η = EF / EP A law relates the useful power (here, final, PF) and the energy yield (η) of a system: P = K (1 - η) η
[A1.1]
This law is governed by a second-degree function, represented by a concave parabola, which has a maximum for a yield of 0.5. The constant K can be explained in economic terms. That is ∏ the apparent productivity of work5 and T the cumulative volume of hours worked: ∏ = GDP / T
[A1.2]
The economic trend is to increase productivity, in particular the productivity of work. It is a case of increasing flows while reducing the time required to produce them. The apparent productivity of the work has been regularly increasing for decades, on a worldwide scale and in particular in France (Figure A1.7).
5 According to INSEE: “In economics, productivity is defined as the ratio, in volume, between a production and the resources implemented to produce it. The production designates the goods and/or services produced. The resources implemented, and also denoted production factors, designate the work, technical capital (installations, machines, tools, etc.), invested capital, intermediate consumption (raw materials, energy, transport, etc.), in addition to factors that are more difficult to grasp although they are extremely important, such as accumulated savoir-faire. The productivity can also be calculated with respect to a single type of resource, work or capital. We therefore talk of apparent productivity. A measure that is often used is the apparent productivity of work. An apparent productivity of the capital can also be calculated […] the apparent productivity of the work only takes into account the single factor of work as the implemented resource. The term ‘apparent’ serves as a reminder that the productivity depends on all the production factors and on the way in which they are combined. The apparent productivity of work is usually measured by relating the wealth created with the work factor: the wealth created is measured by the added value (evaluated as a volume); only the volume of work implemented in the production process is taken into account and it can be quantified in several ways: 1) if the volume of work is measured by the number of hours worked, the term ‘apparent hourly productivity of work’ is used; 2) if the volume of work is measured by the number of people in employment (real people), the term ‘productivity per head’ is used”.
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The final energy intensity of the economy (iF) is the final energy per unit of added value produced: iF = EF / GDP
Figure A1.7. Evolution of the apparent productivity of work in France between 1960 and 2011 (€/h)
According to [A1.2], it results that: EF = ∏ iF T The final power is therefore: PF = ∏ iF T / t
[A1.3]
By combining equations [A1.1] and [A1.3], it results that: K = ∏ iF T / t (1 - η) η Restitution of a constant value for K, from statistical data, is required to validate this interpretation. In fact, this is indeed more or less the case6 (see Figure A1.8). For France: K = 825 GW ± 10% (standard deviation 46 GW)
6 K is a constant for a given energy “generator”. A more in-depth examination would be necessary to assess possible modifications of the eco-energy system which would explain the fluctuations observed for K.
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The final power expressed as a function of the yield, restituted by annual statistical data, approximately follows the theoretical law as shown in Figure A1.9.
Figure A1.8. Constant K ( P = K (1 - η) η ) as restituted by statistical data for France (GW)
Figure A1.9. Final power (GW) as a function of the yield recalculated with the average constant K (red curve) and with the annual values of the K parameters. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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Since 1981, each decade that goes by sees an increase in the energy power of the French system to the detriment of the yield. However, as shown in Figure A1.9, this evolution is slowing, which suggests probable stagnation, or an inverting trend in the coming years, which would be beneficial from the point of view of the economic management of resources and synonymous with a reduction in productivity, for example. A1.5. Case of other European countries The Eurostat database provides series of data on energy for the period 1990– 2011. Similar processing to that detailed above for France in the case of the three other top economic powers in Europe and for some countries with lower GDPs returns different values of K that are roughly constant.
Figure A1.10. Constant K ( P = K (1 - η) η ) restituted by statistical data (Eurostat) for some European countries (GW). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
A1.6. Interpretation and physical justification of degrowth With the decline of fossil resources and energy yields from exploitation on the horizon, and therefore of economic profitability, it has become fundamentally important to modify the economic reasonings that are based on the abundance of easy energy.
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A patrimonial economy should prioritize energy yield, in other words renounce maximization of power. Due to the fact that the current global yield is higher than 0.5, its increase would be expressed as a reduction in power (Figure A1.11).
Figure A1.11. Advanced economies must envisage inverting their productivistic thinking to improve energy performance. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
The power expresses the ratio of energy involved in the transformation, to the time required by the process. Consequently, reducing the power has the effect of slowing down the economy: producing less in absolute terms, but more for the same energy invested and for a longer duration of time, is a new principle which should prevail. Taking into account the processing times reveals, according to the “language” of the second principle of thermodynamics, that the slowing of transformations would come close to reversing and would therefore generate less entropy, in other words less deteriorated, unusable energy. Slowing of the economy, otherwise known as a certain type of degrowth, would be an improvement. The idea of economic degrowth has widely been introduced and justified [DIE 09] and insight provided by the physical approach is important, since the principles on which tangible material things are based necessarily govern all physical systems, even if they are anthropological and dedicated to the resources economy [FER 14]. Although they generally incite rejection and denial (due to the confusion between material degrowth and recession or regression), degrowth has, in fact, begun in developed countries. France is already showing a change of regime, as demonstrated by the accumulation of the points on the power–yield curve (Figure A1.9) and their increased dispersion which reveals instability, for recent years, on approaching a yield of 0.5. These conclusions about the pertinence of a certain form of degrowth, based on the physical approach, are added to those of a few economic studies which simulate various degrowth scenarios. Peter A. Victor has demonstrated that depending on the political economic options that have been selected, a scenario of
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degrowth can lead either to a catastrophe or to an improvement of the economy from the point of view of the GDP, public debt, employment, poverty and greenhouse gas emissions (Figure A1.12) [VIC 08]. The conditions required for favorable degrowth are in particular: – low growth of State expenditure; – stabilization of the population; – carbon tax; – growth of State expenditure to combat poverty; – reinforcement of the local economy; – reduction in the consumption of space; – low growth of investment and productivity; – reduction of working time (with more equal sharing). It is of interest to note that certain conditions that are conducive to economically favorable degrowth (low growth of investment, productivity, reduction of working time) comply entirely with the advice provided by the improvement in energy yield. To mitigate the lack of good sense, we take good note of the fact that the first principle of thermodynamics, in the same way as the second, dictates that infinite growth of anything is an ideal that needs to be assessed. While the economy continues to avoid getting tied up in tangible physical things, the unavoidable degrowth imposed by nature will create a recession, even a devastating regression, which is well-documented in the prospective scenarios given by Dennis Meadows et al. [MEA 12] for the 21st Century and by the considerations of François Roddier concerning the thermodynamics of evolution [ROD 12]. However, the return to physical “good sense” suggests deliberate unleashing of a degrowth which generates prosperity of another order, which is a new progress, according to Tim Jackson [JAC 10], based on an attention of human well-being and to the perennity of the environments. Reinterpretation of the economy from an energy point of view should now be prioritized, as advocated by P.P. Christensen, for example: “Negligence of energy and material resources or their presumed aggregation in primary factors (for the functions K,L) constitutes a central weakness in the neoclassical theory of production. This difficulty will not be overcome simply by adding new production factors (functions KLE and KLEM) and new production relationships to the existing theory. The theory must be substantially reformulated. Considering energy and material flows in a manner that is compatible with physical principles will lead to a different theory” (author’s translation) [CHR 87].
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Figure A1.12. Simulation of two degrowth scenarios in comparison with the trend scenario, by Peter A. Victor [VIC 08]. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
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The postulate stated by Jean-Baptiste Say, which still prevails in the political imagination, is obviously void and invalid. It is in fact a matter of urgency to design a new vision of the economy directed by ethical, biological and physical indicators, in particular those involving energy, in order to orientate the future of our societies towards calm and harmony with the planet. Over and above an energy transition alone, it is necessary to carry out a revision of economic theories, which are too disconnected from physical, ecological, anthropological, cultural contexts, etc., or are quite simply false [KEE 14], to reorientate the development model.
Appendix 2 Explanation of the Calculation Methods for Emissions due to Transport of Merchandise
The original calculation formulae that have been adjusted by the author for combined road transport emissions (section A2.3) are an extension of the calculation protocol that was designed by Jean-Marc Jancovici for ADEME [ADE 10a], of which the foundations are summarized in sections A2.1 and A2.2 (for more details, see [ADE 10a]). A2.1. VKm method: calculation of the emissions from a truck’s kilometerage The consumption per kilometer differs as a function of the load. Calculation of the fuel consumption must therefore take into account the maximum transported load, and the part of the journey carried out unloaded, for a full rotation. D: total distance traveled, including the journey carried out when empty. α: percentage of the distance traveled empty. β: percentage of the maximum payload, when loaded. EF: emissions factor – emissions from combustion of diesel per truck and per kilometer (including previous emissions for the production of diesel). EFV: when empty; EFC: when loaded.
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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The emissions factors are given for various types of trucks in Table 4.1. The format (units and conditions of validity) of the emissions factors that are proposed by the Base Carbone® [ADE 18b] leads unequivocally to the emission calculation formulae, in the application of the generic principle presented in Figure 2.7. The total operational emissions correspond to emissions due to the movement of the vehicle itself (empty) over the entire route, increased by the contribution of the load to the relevant section of the journey: E = β (1 - α) D (EFC - EFV) + D EFV E = D [ β (1 - α) (EFC - EFV) + EFV ]
Figure A2.1. Calculation of the emissions from transport of merchandise is an aggregate of the emissions due to the journey of the empty truck over the entire route and the increase in emissions due to the load for the relevant part of the journey (see Figure A2.2)
WARNING.– The calculation corresponding to Figure A2.2 is erroneous, because the percentage of the maximum payload when loaded (β) should not be applied to the contribution of the vehicle on the loaded journey (β only involves the load).
Figure A2.2. It would be incorrect to reason in terms of the two journey sections (loaded truck/empty truck), because the coefficient β (level of load with respect to the maximum payload) must not be applied to the truck’s contribution, but only to that of merchandise, which would not be adhered to in the expression β (1 - α) D EFc
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185
When the fleet of trucks belongs to the organization in question, the emissions attributable to their manufacture are counted as emissions related to fixed assets. However, when merchandise is sent via transportation companies, it is necessary to count the contribution for the manufacture of trucks in proportion to their use by the entity that is establishing its carbon footprint. At that point, the previous calculation formula needs to be completed in the following way. That is, EFF, the emissions factor related to the manufacture of trucks, expressed in kg CO2e/vehicle.km: E = D [ β (1 - α) (EFC - EFV) + EFV + EFF ] The overall emissions factor is obtained by normalizing the emissions to 1 km: EFvkm = β (1 - α) (EFC - EFV) + EFV + EFF The coefficients α and β are statistical values for France, which can be used by default (see Table 4.1). When the percentage of the distance traveled when empty (α) and the percentage of the maximum payload when loaded (β) can be determined, it is best to prioritize their use. A2.2. TKm1 method: calculation of the emissions from the tonnage and kilometerage of the merchandise (option 1: simple journey) To obtain an emissions factor (EFtkm) that is expressed in kg CO2e/t.km, the emissions (E) previously calculated for a truck traveling on a circuit of distance D are normalized to a kilometer and to the metric ton transported, taking into consideration the maximum payload of the category of vehicle in question, the percentage of the journey that is carried out when empty and the degree of loading: Distance traveled by the merchandise: (1 - α) D Tonnage transported when loaded: β PCmax EFtkm = E / (1 - α) D β PCmax EFtkm = D [β (1 - α) (EFC - EFV) + EFV + EFF ] / (1 - α) D β PCmax EFtkm = [β (1 - α) (EFC - EFV) + EFV + EFF ] / (1 - α) β PCmax EFtkm = [ (EFC - EFV) + (EFV + EFF) / β (1 - α) ] / PCmax
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Figure A2.3. Using the “tonne-kilometer” method, the emissions are obtained by multiplying the emissions factor EFtkm by the tonnage of freight and by the distance that it travels between the pick-up point and the deposition location (the parameters related to the vehicle are implicit)
A2.3. TKm2 method: calculation of the emissions from the tonnage and kilometerage of the merchandise (option 2: complex journey) A.2.3.1. Calculation tables When a transportation company is used, the situation is complicated because collection, distribution and transport between platforms can involve various categories of trucks for mixed merchandise from several different clients. It is not easy to evaluate the quantity of fuel that can be attributed to particular merchandise. For the calculation of emissions from transport, Jean-Marc Jancovici had initially put forward a remarkable calculation method for the Bilan Carbone®, on the basis of which we have demonstrated regularities that can be expressed by linear equations in six fields of validity determined by: – the ratio of weight dispatched to the weight of a full pallet of merchandise; – the destination. Three categories of destination1 need to be considered depending on their rural nature or, on the contrary, their more or less urban nature (see section A2.3.2): – rural areas where the distances covered by distribution circuits are large (LW for “large wholesaler”); – on the contrary, highly urbanized areas (SW for “small wholesaler”); – the intermediate cases (MW for “medium wholesaler”).
1 For collection, the Bilan Carbone® method considers a statistical average distance for the transport of particular merchandise that is independent of the area.
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187
NOTATIONS AND DEFINITIONS.– P: tonnage of merchandise (expressed in kg). PP: weight of a full pallet of the merchandise in question (required for calculation of the density of the merchandise) (expressed in kg). ∆: distance between the capitals of the dispatch and destination areas. “Small wholesaler” (SW) destination area If P < 4.0 PP
E = (0.01260 + 1.064.10-4 ∆ ) P
If 4.0 PP ≤ P < 23.8 PP
E = (0.00500 + 1.064.10-4 ∆ ) P
If 23.8 PP ≤ P < 33.1 PP
E = (0.00192 + 1.064.10-4 ∆ ) P
“Medium wholesaler” (MW) destination area If P < 4.0 PP
E = (0.02077 + 1.064.10-4 ∆ ) P
If 4.0 PP ≤ P < 23.8 PP
E = (0.00825 + 1.064.10-4 ∆ ) P
If 23.8 PP ≤ P < 33.1 PP
E = (0.00408 + 1.064.10-4 ∆ ) P
“Large wholesaler” (LW) destination area If P < 4.0 PP
E = (0.03725 + 1.064.10-4 ∆ ) P
If 4.0 PP ≤ P < 23.8 PP
E = (0.01479 + 1.064.10-4 ∆ ) P
If 23.8 PP ≤ P < 33.1 PP
E = (0.00844 + 1.064.10-4 ∆ ) P
In the field where P ≥ 33.1 PP, the equations from the field [23.8; 33.1[ could be used, given that the emissions will be overestimated, or use could be made of the Bilan Carbone® calculation tools, after participating in the required training provided by the Institut de Formation Carbone.
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Figure A2.4. Chart providing a basis for the selection of the field to which the emission calculation formulae for the transport of merchandise refer
In the event that the transport crosses national borders, an approximate solution can consist of: – characterizing the population density of the foreign destination zone (extending to the size in the order of an average French department) to find an equivalent in the typology of French departments in three population classes; – determining the distance ∆ between the capital in the dispatch area and the main town in the foreign area in question. The principle is obviously the same for incoming transport. A2.3.2. Classification of French departments from the point of view of merchandise distribution transport The calculation method, initially conceived by Jean-Marc Jancovici for processing combined transport, in the context of the Bilan Carbone®, takes into
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consideration three categories of departments depending on the size of their populations (distribution loops are then longer in rural departments): – departments with population less than 500,000 inhabitants (density < 65 inhab/km2), with long distribution circuits (LW for “large wholesaler”); – departments with population included between 500,000 and 1,000,000 inhabitants (65 < density < 155 inhab/km2), with average distribution circuits (MW for “medium distribution”); – departments with population greater than 1,000,000 inhabitants (density > 155 inhab/km2), with short distribution circuits (SW for “small distribution”). In the list below, this classification relies on data collected by INSEE for 20152 [INS 17]. It is therefore necessary to identify the category of department to which the merchandise is dispatched to proceed with calculation using the method presented above. (01) Ain
MW
(48) Lozère
LW
(02) Aisne
MW
(49) Maine-et-Loire
MW
(03) Allier
LW
(50) Manche
MW
(04) Alpes-de-Haute-Provence
LW
(51) Marne
MW
(05) Hautes-Alpes
LW
(52) Haute-Marne
LW
(06) Alpes-Maritimes
SW
(53) Mayenne
LW
(07) Ardèche
LW
(54) Meurthe-et-Moselle
MW
(08) Ardennes
LW
(55) Meuse
LW
(09) Ariège
LW
(56) Morbihan
MW
(10) Aube
LW
(57) Moselle
SW
(11) Aude
LW
(58) Nièvre
LW
(12) Aveyron
LW
(59) Nord
SW
(13) Bouches-du-Rhône
SW
(60) Oise
MW
(14) Calvados
MW
(61) Orne
LW
(15) Cantal
LW
(62) Pas-de-Calais
SW
(16) Charente
LW
(63) Puy-de-Dôme
MW
(17) Charente-Maritime
MW
(64) Pyrénées-Atlantiques
MW
2 The users of previous Bilan Carbone® calculation tools may notice in certain cases a difference in the calculation result of transport emissions with respect to the value produced by the TKm2 method, because the status of certain departments was updated later, in 2015.
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(18) Cher
LW
(65) Hautes-Pyrénées
LW
(19) Corrèze
LW
(66) Pyrénées-Orientales
LW
(21) Côte-d’Or
MW
(67) Bas-Rhin
SW
(22) Côtes-d’Armor
MW
(68) Haut-Rhin
MW
(23) Creuse
LW
(69) Rhône
SW
(24) Dordogne
LW
(70) Haute-Saône
LW
(25) Doubs
MW
(71) Saône-et-Loire
MW
(26) Drôme
MW
(72) Sarthe
MW
(27) Eure
MW
(73) Savoie
LW
(28) Eure-et-Loir
LW
(74) Haute-Savoie
MW
(29) Finistère
MW
(75) Paris
SW
(2A) Corse-du-Sud
LW
(76) Seine-Maritime
SW
(2B) Haute-Corse
LW
(77) Seine-et-Marne
SW
(30) Gard
MW
(78) Yvelines
SW
(31) Haute-Garonne
SW
(79) Deux-Sèvres
LW
(32) Gers
LW
(80) Somme
MW
(33) Gironde
SW
(81) Tarn
LW
(34) Hérault
SW
(82) Tarn-et-Garonne
LW
(35) Ille-et-Vilaine
SW
(83) Var
SW
(36) Indre
LW
(84) Vaucluse
MW
(37) Indre-et-Loire
MW
(85) Vendée
LW
(38) Isère
SW
(86) Vienne
LW
(39) Jura
LW
(87) Haute-Vienne
LW
(40) Landes
LW
(88) Vosges
LW
(41) Loir-et-Cher
LW
(89) Yonne
LW
(42) Loire
MW
(90) Territoire de Belfort
LW
(43) Haute-Loire
LW
(91) Essonne
SW
(44) Loire-Atlantique
SW
(92) Hauts-de-Seine
SW
(45) Loiret
MW
(93) Seine-Saint-Denis
SW
(46) Lot
LW
(94) Val-de-Marne
SW
(47) Lot-et-Garonne
LW
(95) Val-d’Oise
SW
For a color version of this table, see www.iste.co.uk/rossignol/climatic.zip
Appendix 3 Accounting of Emissions due to the Production of Fixed Assets
A3.1. Methodological information Fixed assets are included in the accounting of greenhouse gas emissions that are generated by the activity of an organization. Emissions from the manufacture of fixed assets are generated only once, and they are recorded on the balance sheet on a pro rata basis throughout the year, with respect to their useful life. This annual fraction of initial emissions is called “carbon amortization” by analogy with accounting amortization. The Bilan Carbone® method has identified the lifetime of the fixed asset as the duration of the amortization period recommended by the Administration. For various reasons (physical, technical, legal), it is possible to select different amortization periods. Carbon amortization of a given asset can therefore fluctuate from one entity to another. To base calculation of carbon amortization on more physical notions than accounting amortization, it is possible to consider the age of the fixed asset and the expected lifetime. This can be estimated from experience or on the basis of statistical data. Of course, this assessment is also subject to discrepancies. However, the sensitivity of the result to its variation is lower than that for accounting amortization (except when the age of the asset is close to the end of life, but in this case the uncertainty of the lifetime is small).
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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This study1 therefore proposes a theoretical development of the consideration of emissions from the production of fixed assets, depending on a degressive method based on age and lifetime. The degressivity allows most of the emissions to be noted in advance, more in accordance with physical reality, and with an accounting approach that is more appropriate for the application of a discounted rate to future emissions (considering that a quantity of CO2 emitted in the past is less damaging than the same quantity emitted in the future). Sensitivity to the error associated with the estimate of the lifetime is examined and has turned out to be relatively low. A case study analyzes the differences obtained for a real-life fleet of fixed assets, using the standard approach and the method proposed here. It demonstrates that this restitutes an average carbon amortization that is a little less significant and more spread out in time, as the fleet of assets evolves. A3.2. Preliminary justifications For the distribution of emissions from the manufacture of a fixed asset over a certain period of time, meaning for the calculation of what we will call “carbon amortization“, the Bilan Carbone® method makes reference to the duration of the accounting amortization period. The amortization method is linear and consequently its annual value is constant. This method has the merit of being simple; however, the link is relatively weak between an accounting convention and the physical phenomena of greenhouse gas emissions that are observed in the manufacture of an asset destined for long-term use. Accounting amortization periods, which vary according to the operators for accounting reasons, determine the methods of taking into account the “spread” of initial emissions. The calculation can be based on less arbitrary data, such as the real age of the asset and its probable lifetime, either expected or determined statistically. Even if this duration is also appreciable in different ways, at least it corresponds to a physical reality that is more naturally associated with initial emissions from manufacture. In addition, it is useful to notice these emissions as early as possible to encourage economic players to implement drastic and immediate action in the event of renewal of fixed assets. Noticing them later is contrary to the needs of the fight against climate change. Voluntarily, the Greenhouse Gas Protocol, and ISO 14064 take into account all the emissions from the manufacture of assets in the year of their acquisition. For all these reasons, we propose a degressive carbon amortization
1 Study finalized on July 20, 2009, by extending a suggestion made on the forum for users of the Bilan Carbone®, on July 1, 2008, and communicated to ADEME for information.
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over the lifetime of fixed assets, which logically associates the physical realities and which confers the maximum initial “carbon weight” of the fixed assets in the short term. According to the international accounting standard written by the Commission of European Communities: “Property, plants and equipment are tangible items that: a) are held for use in the production or supply of goods or services, for rental to others, or for administrative purposes; and b) are expected to be used over more than one period. […] Useful life is: a) the period over which an asset is expected to be available for use by an entity; or b) the number of production or similar units expected to be obtained from the asset by an entity” [COM 08, p. 73]. “The useful life of an asset is defined in terms of the asset’s expected utility to the entity. The asset management policy of the entity may involve the disposal of assets after a specified time or after consumption of a specified proportion of the future economic benefits embodied in the asset. Therefore, the useful life of an asset may be shorter than its economic life. The estimation of the useful life of the asset is a matter of judgement based on the experience of the entity with similar assets” [COM 08, p. 78]. “Depreciation (amortization) is the systematic allocation of the depreciable amount of an asset over its useful life” [COM 08, p. 216]. In summary, the standard emphasizes the fact that the accounting amortization period is not normalized and that it can be shorter than the economic lifetime of the asset.
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A3.3. Mathematical basis NOTATIONS.– a: age of the fixed asset in the reporting year. DV: economic lifetime of the fixed asset. D: duration of the accounting amortization period. AL: linear carbon amortization based on the duration of the accounting amortization period. AD: degressive carbon amortization based on the lifetime and age of the asset. E: production emissions.
A3.3.1. Calculation of the linear carbon amortization Linear amortization based on the accounting period: AL = E / D
A3.3.2. Calculation of degressive carbon amortization based on the age and lifetime of the asset The degressivity can be expressed using the following simple law: AD = AD0 – β a When a = DV: AD = 0 Therefore β = AD0 / DV AD = AD0 (1 – a / Dv)
[A3.1]
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Figure A3.1. 1) Annual degressive carbon amortization (AD); 2) its cumulation over a number of years (e)
A3.3.2.1. Calculation of AD0 The cumulative sum of carbon amortization over the entire lifetime (equal to the total emissions from production) is given by the integral of AD(a). These cumulative emissions, counted as the asset ages, are given by: e(a) = ∫AD da e(a) = ∫ AD0 (1 - a / Dv) da e(a) = (-AD0 / DV) a2 / 2 + AD0 a + k For a = 0 we have: e(a) = 0 therefore k = 0
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For a = Dv: e(a) = E therefore: E = -AD0 Dv / 2 + AD0 Dv that is: E = AD0 Dv / 2 Hence: AD0 = 2E / Dv By substituting into [A3.1], the annual carbon amortization expression as a function of the age of the asset is: AD = (2E / DV) (1 – a / DV)
[A3.2]
Since the lifetime of the asset is unequivocal, it is useful to analyze the variation in amortization as a function of the fixed lifetime, for a given age of the fixed asset. A3.4. Variation in the degressive carbon amortization based on lifetime Now considering “a” as a parameter and DV as the variable, the derivative of the degressive amortization with respect to the lifetime according to the expression [A3.2] is: d(AD) / d(DV) = -2 E / (DV)2 + 4a E / (DV)3 d(AD) / d(DV) = [ 2 E / (DV)2 ] (2a / DV - 1) d(AD) / d(DV) = 0 when ( 2a / DV - 1) = 0 meaning when Dv = 2a Let Dvm be this lifetime for which the depreciation passes through a maximum ADm, for a given age of fixed asset: DVm = 2a ADm = (2E / DVm) (1 - a / DVm) ADm = (E / a) (1 - 1/2 ) = E / 2a
[A3.3]
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Figure A3.2. Variation in the degressive carbon amortization (metric ton 2 of carbon equivalent, denoted t Ce ) for various ages of a fixed asset as a function of its lifetime (original emissions from production: 100 t Ce). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
A3.5. Analysis of the sensitivity to the error in the selected lifetime The estimation of the lifetime of an asset can be based on previous observations, for similar assets. It can also be estimated on the basis of statistics. Tangible assets to determine the expected lifetime of vehicles and buildings are given in section A3.7. However, it will be observed that for much longer lifetimes than the age of the assets observed in the reporting year, the sensitivity of amortization to the variation in the lifetime is low (curves 1–3 in Figure A3.3). This sensitivity is, however, important for very recent assets with a short lifetime (curve 1), but in this case, the uncertainty related to the lifetime is low. The sensitivity of amortization for a lifetime that is scarcely greater than the observed age, is reduced with age, as shown on curves 2 and 3. However, the linear amortization based on the accounting period which, we recall, can depend on considerations only related to accounting, is highly sensitive to wide-ranging variations in the period’s duration (curve 4).
2 We can normalize the quantity of CO2 equivalent to the weight of carbon alone (atomic mass 12 g) that is contained in the molecule of carbon dioxide (molar mass 44 g). The ratio between the two units, CO2 equivalent (CO2e) and carbon equivalent (Ce), is 44/12 or 12/44 depending on the direction of the conversion (take care with the direction: the value in CO2e must be greater than in Ce!).
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Figure A3.3. Variation in the degressive carbon amortization (t Ce/yr) for various ages of a fixed asset ((1), (2), (3)) as a function of its lifetime, by comparison with the linear carbon amortization based on the accounting amortization period (4). For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
A3.6. Application to a real-life fleet of fixed assets The chosen example relates to a set of stainless steel vats used by an agri-food company. The fleet consists of 231 vats with a volume between 3.5 and 2,160 hectoliters, for a total weight of 551 metric tons. In the reporting year, the youngest vat was 4 years old and the oldest was 28 years old. A3.6.1. Linear amortization based on the accounting period The linear amortization for the reporting year, based on the accounting period, has been calculated for various linear accounting amortization periods, in 5-year blocks (for this type of material, it is typically 10 years). When the period is extended, the amortization diminishes, but the fleet that has not yet been amortized increases. The carbon amortization thus fluctuates between 2.1 and 19.2 t Ce per year, around an average of 13.7 t Ce, with a standard deviation of 6.7 t Ce.
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Figure A3.4. Linear carbon amortization of the fleet for the reporting year as a function of the chosen period of accounting amortization. For a color version of this figure, see www.iste.co.uk/rossignol/climatic.zip
A3.6.2. Comparison of the evolution of carbon amortization with both approaches For machinery, the duration of the accounting amortization period is currently 10 years. The oldest vats in the fleet under consideration are 28 years old. The operator considers that their lifetime is in the order of 50 years. As shown in Table A3.1 and in the diagrams in Figure A3.5, the degressive amortization method proposed, based on the age and lifetime of fixed assets, lessens the differences and reduces the variations in carbon amortization of the fleet of fixed assets as the years pass. The average amortization is also reduced. Even in the case of a shorter lifetime, of 30 years (unfavorable from the point of view of sensitivity), the observation is similar. Carbon amortization (t Ce/yr)
Average
Standard deviation
Linear method based on accounting amortization (10 years)
18.4
9.9
Degressive method based on age and lifetime (30 years)
14.8
5.3
Degressive method based on age and lifetime (50 years)
11
4.3
Table A3.1. Average and standard deviation of the carbon amortization as a function of the calculation method
200
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Figure A3.5. Annual carbon amortization for the entire fleet of vats (t Ce): (1) linear, based on the duration of accounting amortization period (10 years); (2) degressive, based on age and lifetime (50 years); (3) degressive, based on age and lifetime (fictitious, for comparison: 30 years)
A3.7. Determination of the lifetime of fixed assets A3.7.1. Vehicles The Guide to emissions factors provided by the Bilan Carbone® method [ADE 10a, p. 23, 33, 74-77] gives estimates of the average distance traveled by the various vehicles, both light and heavy, over their entire lifetime. If no other tangible assets are available, the probable lifetime of a vehicle and the average distance traveled on an annual basis can be calculated from the charts in Figure A3.6.
Appendix 3
201
Figure A3.6. Statistical kilometerage traveled over the lifetime of the vehicles, for various categories [ADE 10a]
A3.7.2. Buildings There are statistics that provide the average lifetime of various categories of buildings, and only the following three examples will be discussed here: – French logistics real estate: in 2008, 23% of real estate is more than 20 years old and the real estate contains warehouses aged over 30 years [OBL 07, OBL 08]; – French housing stock: the average age of housing is 56 years3; – French tertiary real estate: 70% of the tertiary real estate was more than 20 years old in 2001 (details per industry given in the table on page 5 of the publication) [GIR 01].
3 Xerfi, quoted by: http://www.centreouest-immo.com/actu_diagnostic-et-ensuite--_143.htm.
Appendix 4 Emissions Related to Journeys Made Between the Brickworks and Employees’ Places of Residence: Analysis of Sensitivity to Calculation Hypotheses (Case Study 1)
This analysis refers to the table of data given in section 6.1.2, under the heading “Investigation into journeys made by people between their residence and the brickworks” and in section 6.1.3.6.1. The essential point is to extrapolate the cumulative distances traveled by automobiles between places of residence and workplaces, to the size of the company workforce (72 employees), per vehicle category (administrative power and type of fuel), on the basis of information provided by the 49 people who have answered an investigation. In addition, since the company cars are also used for journeys from home to the workplace, it is necessary to process them in such a way as to avoid counting fuel consumptions twice. A4.1. Case of company cars The annual consumption of the five vehicles is 10,124 liters. This quantity includes consumption from journeys made as part of work, and consumption due to journeys between places of residence and the brickworks. There are two possible calculation options.
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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A4.1.1. Option 1 (O1) Consumption is not allocated to the two types of journeys for company cars. The total fuel is counted under professional journeys. In this case, the five company cars need to be removed from the sample and from the total workforce to avoid counting them twice. A4.1.2. Option 1a (O1a) The five company cars must not feature in the total workforce, but they may be considered to remain significant in the definition of the sample (effectively, they are also significant in the statistical representation of the kilometerage of the diesel vehicles for journeys from places of residence to workplaces). A4.1.3. Option 2 (O2) From the kilometerage traveled by the company cars between places of residence and the brickworks and from a hypothesis made about their average consumption of diesel (e.g. 5 liters per 100 km), we reconstitute the quantity of fuel consumed for journeys made from places of residence to the brickworks, which are deducted from the 10,124 liters. In this case, the company cars can be kept in the sample and in the total workforce. Cumulative kilometerage of the five company cars on private journeys: 68,640 km. Estimated consumption of diesel: 5 l/100 km, that is, 3,432 liters. Consumption in the context of work: 10,124 - 432 = 6,692 liters. A4.2. Case of pedestrians and cyclists A4.2.1. Hypothesis 1 (H1) All pedestrians and cyclists have given answers in the investigation. In this case, they must be removed from the sample before extrapolation to all personnel. A4.2.2. Hypothesis 2 (H2) The personnel that have not given answers to the investigation also include pedestrians and cyclists in the proportion appearing in the investigation with the
Appendix 4
205
sample of 49 people. In this case, these must be taken into account in the sample (but not the kilometerage that they travel, which does not consume fuel). From a learning point of view, to demonstrate the differences resulting from the choice of option, all cases are calculated below. A4.3. Calculation of the emissions due to journeys made by employees from their places of residence to the workplace – Total workforce
72
– Number of company cars
5
– Number of pedestrians and cyclists in the sample
4
Pertinent sample (e)
Extrapolated workforce (E)
Extrapolation coefficient (E/e)
O1, H1
49 - 5 - 4 = 40
72 - 5 - 4 = 63
1.575
O1, H2
49 - 5 = 44
72 - 5 = 67
1.523
O1a, H1
49 - 4 = 45
72 - 5 - 4 = 63
1.400
O1a, H2
49
72 - 5 = 67
1.367
O2, H1
49 - 4 = 45
72 - 4 = 68
1.511
O2, H2
49
72
1.469
For each person, it is necessary to remember to multiply the distance from the place of residence to the brickworks: – by 2, for the outward and return journeys; – by the number of daily outward-return journeys; – by the number of days worked (220). Cumulative kilometerage for the sample, with or without taking into consideration the company cars (CC): Diesel without CC
Diesel with CC
Petrol
]0-5] hp
62,920
122,760
90,200
[6-10] hp
40,480
49,280
67,320
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Climatic Impact of Activities
Extrapolation of the kilometerage to the total relevant workforce, as a function of the various cases: Diesel without CC
Diesel with CC
Petrol
]0-5]
[6-10]
]0-5]
]0-5]
O1, H1
99,099
63,756
142,065 106,029
O1, H2
95,810
61,640
137,350 102,510
hp:
[6-10]
[6-10]
O1a, H1
171,864 68,992
126,280 94,248
O1a, H2
167,856 67,383
123,335 92,050
O2, H1
185,504 74,468
136,302 101,728
O2, H2
180,382 72,411
132,539 98,919
For each category of vehicle, the emissions factor (kg CO2e/km) which is to be applied a priori (we will see that further qualification is required in certain cases), must add in the three contributions (combustion, previous and production), and the Base Carbone® gives the following values: Diesel
Petrol
]0-5] hp
0.230
0.234
[6-10] hp
0.261
0.272
The product of kilometerage and the emissions factor gives the emissions related to journeys from places of residence to the brickworks (kg CO2e): Diesel without CC
Diesel with CC
Petrol
]0-5]
[6-10]
]0-5]
]0-5]
[6-10]
O1, H1
22,793
16,640
33,243
28,840
101,516
O1, H2
22,036
16,088
32,140
27,883
98,147
hp:
[6-10]
Total
O1a, H1
39,529 18,007
29,550
25,635
112,721
O1a, H2
38,607 17,587
28,860
25,038
110,092
O2, H1
42,666 19,436
31,895
27,670
121,667
O2, H2
41,488 18,899
31,014
26,906
118,307
Appendix 4
207
The maximum difference, between scenarios O2H1 and O1H2, is approximately 20%, in other words emissions estimated to be 110,000 ± 10% kg CO2e. The total emissions in option 2 needs to be corrected to guard against incorrect incorporation of the carbon amortization for company cars into the emissions factor. Indeed, since the professional part of company cars is differentiated as a whole, here the contribution made to their production must be deducted to avoid being counted twice, because it must be counted for the carbon amortization of fixed assets. For all categories of vehicle, the emissions factor for production is the same: 0.040 kg CO2e/km [ADE 18b]. Since the cumulative kilometerage of company cars, already calculated above, is 68,640 km, the emissions that must be deducted from the total are: 68,640 × 0.040 = 2,746 kg CO2e We select scenario O2H2, which is more realistic, but which does not have the lowest level of emissions. A4.3.1. Emission balance E6.1(O2H2) = 118,307 – 2,746 = 115,562 kg CO2e E6.1(O2H2) = 116 t CO2e rounded to 120 t CO2e with the following conditions: – take into account the company cars for journeys from places of residence to work; – statistical distribution of pedestrians and cyclists for the entire workforce spectrum; – the consumption of fuel by company cars is spread across the two groups: journeys from place of residence to work/journeys in the context of work; – emissions from production of company cars are counted in their entirety in the group for carbon amortization of fixed assets.
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Index
C, D, E carbon amortization, 67, 105, 106, 112, 147, 148, 150, 152, 159, 191, 192, 194–200, 207 dashboard, 164 destockage, 5, 8, 11, 28, 79, 125, 134, 150, 152, 153 dioxide, 1–6, 8, 10–13, 16, 18, 20, 21, 23, 27, 28, 44, 45, 49, 55, 56, 80, 86, 98, 117, 118, 121, 123–125, 127, 129, 134–136, 168, 197 chlorofluorocarbons, 16 climate footprint, 15, 33, 47, 72, 82, 87, 147 CO2 equivalent, 23, 24, 28, 30, 55, 56, 117, 197 combination of balances, 38, 76, 136, 137, 179 combustion, 1, 6, 8–13, 22, 24, 28–30, 41, 43, 44, 47–49, 53, 54, 61, 62, 69, 79, 80, 86, 88, 91, 93, 98, 108, 118–123, 132–135, 138–141, 168, 183, 206 cycle, 3, 5, 6, 8–11, 13, 19, 20, 28, 39, 43, 63, 79, 80, 83, 114, 123, 135, 136, 139, 148, 156 biogenic, 5 carbon, 5, 6, 8, 11, 28
long, 5, 6, 28 short, 5, 6, 8, 11, 19, 28, 80, 135 water, 11, 13 deforestation, 8, 152, 153 emissions additional, 6 direct, 26, 34, 41, 47, 49, 68, 72, 88, 98. 99, 124, 127, 132, 134, 146, 147 indirect, 26, 34, 38, 42, 69, 81, 117, 132, 133, 163 end of life of products, 26, 36, 42, 72, 73, 83, 95, 139, 143, 163 F, G, H fermentation, 4, 6, 11, 12, 19, 24, 36, 42, 49, 79, 129, 132, 134, 135, 143, 156, 163 anaerobic, 6, 19, 49, 79, 135, 163 flow, 15, 17, 20, 24, 25, 37–39, 43, 44, 49, 62, 63, 74, 86, 96, 97, 128–133, 136, 137, 167–169, 174, 179 geocycle, 1, 3, 9, 10 GWP (Global Warming Potential), 6, 8, 18–21, 23, 25, 30, 27, 28, 128, 129, 140, 144, 146 hydrobromocarbons, 16 hydrochlorocarbons, 16
Climatic Impact of Activities: Methodological Guide for Analysis and Action, First Edition. Jean-Yves Rossignol. © ISTE Ltd 2020. Published by ISTE Ltd and John Wiley & Sons, Inc.
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Climatic Impact of Activities
hydrochlorofluorocarbons, 16 hydrofluorocarbons, 16, 21 I, M, N infrared, 1, 2, 16, 17, 21 manufacturing of fixed assets, 36, 42, 66, 67, 94, 111, 191 of inputs, 36, 42, 49, 63, 88, 99, 100, 134 of tangible assets, 66, 67 mapping of processes, 39 methane, 2, 6, 16, 19, 20, 22, 23, 25, 28, 30, 49, 79, 135, 144, 145, 155, 156 methanization, 22, 49, 156 movement of people, 36, 47, 82, 91, 107, 147, 148, 163 nitrogen trifluoride, 16, 20 nitrous oxide, 16, 20, 49, 128, 144, 145, 156 P, R, S perfluorocarbons, 16, 21 photosynthesis, 5, 6, 8, 11, 12, 19, 20, 28, 43, 44, 98, 121, 134, 135
physical economy, 167, 170, 172 radiative forcing, 17, 18, 19, 27 regulatory greenhouse gas emissions balance, 40, 43, 50 scope of emissions, 35, 36, 42, 68, 70, 81, 132 sulfur hexafluoride, 16, 20 sulfuryl fluoride, 16, 20 T, U, W transport of merchandise, 36, 47, 50, 51, 59, 61, 89, 107, 118, 127, 147, 148, 163, 183, 203 uncertainty, 39, 73–76, 78, 79, 105, 108, 110, 143, 150, 154, 163, 192, 197 use of energy, 30, 36, 47, 48, 88, 97, 124, 134 of products, 36, 68, 70, 72, 83, 95, 112 waste treatment, 24, 26, 35, 36, 42, 62, 63, 65, 93, 110, 111, 116, 132, 146
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