The Entropy Crisis Downloaded from by on 04/25/18. For personal use only.

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3 Guy Deutscher Tel Aviv University, Israel World Scientific NEW JERSEY LONDON SINGAPORE B E I J I N G SHANGHAI HONG KONG TA I P E I CHENNAI

4 Published by World Scientific Publishing Co. Pte. Ltd. 5 Toh Tuck Link, Singapore USA office: 27 Warren Street, Suite , Hackensack, NJ UK office: 57 Shelton Street, Covent Garden, London WC2H 9HE British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library. Cover Illustration: Aline Deutscher THE ENTROPY CRISIS Copyright 2008 by World Scientific Publishing Co. Pte. Ltd. All rights reserved. This book, or parts thereof, may not be reproduced in any form or by any means, electronic or mechanical, including photocopying, recording or any information storage and retrieval system now known or to be invented, without written permission from the Publisher. For photocopying of material in this volume, please pay a copying fee through the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, USA. In this case permission to photocopy is not required from the publisher. ISBN ISBN X ISBN (pbk) ISBN (pbk) Printed in Singapore.

5 To Barak, Eyal, Nimrod, Roï, Noga and Ori as a Vade Mecum for life in a changing world v

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7 Contents Introduction 1 Chapter 1. Dealing with Entropy on a Daily Basis Entropy in the household An example of an entropy crisis at home Where does all the disorder go? Disorder and pollution Entropy and the second law of thermodynamics Water desalination Heat transfer Entropy and the states of matter From the household to the biosphere 11 Chapter 2. A Short History of the Biosphere The billion year time scale The apparition of life Photosynthesis Photosynthesis and entropy reduction Photosynthesis and the green color of plants The ozone layer and the spread of life The biosphere on the 100 million year time scale Carbon dioxide atmospheric content and temperature: the greenhouse effect The infrared radiation Greenhouse gases Climate evolution and carbon storage Carbon storage: carbonates and fossil fuels Carbon storage in carbonates on the billion year time scale 22 vii

8 viii The Entropy Crisis Carbon storage as fossil fuels on the 100 million year time scale Formation of coal deposits: the carboniferous age Oil and gas deposits Ice ages The last 10 million years 27 Chapter 3. How Much Energy do We Need? Different forms of energy and power Energy conversion Energy use and entropy release Heat rejection Entropy release Energy needs and costs Food energy Food versus other energy needs A family s energy needs A family s energy costs Food energy costs The different energy costs Energy needs at the society level and the entropy problem Can society survive with a lower entropy release? 50 Chapter 4. Entropy in Thermodynamics and Our Energy Needs Entropy in thermodynamics Heat and mechanical work as two forms of energy: the first law of thermodynamics Thermodynamic cycles Work performed in a thermodynamic cycle The Carnot cycle Entropy change: introducing the second law of thermodynamics 62

9 Contents ix Energy, entropy and free energy Entropy at the molecular level Energy needs and man generated entropy 68 Chapter 5. Climate Change: What We Know and What We Don t Time scale and temperature scale The earth s temperature over the last few hundred thousand years How well understood is the periodicity of interglacial periods The Milankovitch cycles Problems with the Milankovitch cycles Towards a longer interglacial period? The CO 2 cycles Anthropogenic temperature changes The CO 2 anthropogenic footprint The temperature rise in modern times Evolution of the temperature since 1900: the start of anthropogenic effects Expected temperature rise in the 21 st century Consequences of further temperature rise: ice melting Climate changes in space and time: back to entropy The entropic meaning of sustainable development Concluding remarks 101 Chapter 6. Fighting Entropy with Technology Motivation for fighting entropy increase: ensuring climate stability By how much do we need to reduce anthropogenic entropy release Entropy management strategies 106

10 x The Entropy Crisis Minimizing irreversibility processes by developing technology I: the motocar The all-electric motorcar The battery problem The hydrogen car But where will the electricity for the all-electric car come from? Minimizing entropy production by improving technology II: space heating and cooling Two types of solutions: improved insulation or increased thermal mass Keeping the temperature constant is a question of time scale Towards zero entropy release buildings Reducing entropy release in industry Energy generation impact on global entropy release Energy generation from renewable sources Biomass Solar heating Thermal solar electricity Photovoltaics Wind turbines Non renewables: fossil fuels versus nuclear Improving the use of fossil fuels Pros and cons of carbon storage Nuclear power plants Transport of electrical power 132 Chapter 7. Towards a World without Fossil Fuels Increasing entropy and increasing energy needs The retreat of oil How much oil is left anyhow? Replacing oil and gas by coal for residential heating? Can we replace oil for transportation? 141

11 Contents xi 7.6. Can coal be displaced as the major primary fuel? Displacing coal with renewables Competition for land space Production potential of solar power in desert areas The potential for wind power production Distributed renewable power Solar water heaters Distributed photovoltaics About costs 151 Chapter 8. A Changing World A realistic objective The supply side Distributed power supply Wind power Large scale solar electricity The importance of improved electricity networks for the implementation of renewables on a large scale Switching back to coal Nuclear energy as a replacement for coal fired plants Reducing the power consumed in developed countries The case for the electric car Family energy budget and power spent at the society level The dangers Is there a climate run away? Is carbon dioxide atmospheric content a sufficient indicator? Food supply Renewables and water 169 Index 171

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13 Introduction The biosphere is the world in which we live. Compared to the size of the earth, the biosphere is a thin layer surrounding the earth s surface, extending a few kilometers above and below it. This is where all living organisms and their residues are to be found. This is where mankind has developed, in intimate relation with its surroundings, what we often call the environment. We know that our life has always been dependent on it, and always will. Hence our deep concern when changes, maybe harmful to us, occur in the biosphere, possibly due to the activity of mankind. Do these fears have a scientific basis, or are they grossly exaggerated? For instance, is climate change a real threat? And what is more harmful to the biosphere, to burn more fossil fuels, or to build and operate more nuclear reactors? Today these issues are in the public domain and, in the end, it will be the people who will decide what should or should not be done. This is why I believe it is important for everybody to understand the nature of the issues at hand. It turns out that an intelligent discussion requires some familiarity with a concept called entropy. While everybody is familiar with the concept of energy, only a few, mostly scientists, know about entropy. In order to understand that there is a deep connection between the energy crisis, by which we mean that we may soon run out of fossil fuels, and damage to the environment, it is necessary to understand the concept of entropy. According to the laws of thermodynamics, this damage is one aspect of an increase in entropy (or disorder at the molecular scale) in the biosphere, which cannot be avoided when we burn fuel. This increase in entropy is more subtle than the loss of fuel supply, but instinctively it is the one that we fear more. As we shall see, the danger lies not so much in the fact that we are burning fuel, but rather in the rate at which we do this. 1

14 2 The Entropy Crisis If we run out of fossil fuels it is evidently because we have been burning them so fast, and so inefficiently, and this is precisely the reason why the effects of the increase in entropy are now there for everybody to see. I wish to thank Rafael Ben Zeev for prompting me to write this little book; my wife Aline for her continuing encouragements and well taken criticisms of the whole manuscript; my son Daniel for his very critical reading of Chapter 4 where the thermodynamic concept of entropy is introduced, and insisting that it should be made accessible to high school level students; to my daughter Nathalie for making some good points on the first chapters; to my friend Gila for her remarks on my way of writing English; to my friend Michael for his sharp criticism of Chapter 5; and to Jacques Friedel for several and enlightening discussions on the issues raised by the use of nuclear energy for electricity production. Guy Deutscher June 2008