Chapter 2. Emergy and Economics
It is a fact that:
Real wealth is food, fuel, water, wood for houses, fiber for clothes, raw minerals, electricity, information.
A country is wealthy that has more of this real stuff used per person.
Money is only paid to people and is not proportional to real wealth.
Prices and costs are inverse to real wealth.
When resources are abundant, standard of living is high, but prices are low.
When resources are scarce, prices are high, more money goes to bring resources, a few people get rich, but the net contribution to prosperity is small.
Real wealth is mostly the work of nature and has to be evaluated with a scientific measure, EMERGY.
– Howard T. Odum
Table of Contents
What We Hope To Accomplish in this Chapter
Money and Other Forms of Surrogate or Paper Wealth
Determination of Feasibility of Nuclear Fission
Does the Government Do Anything Useful?
Can the Government Solve Social Problems?
Economic Activity: Emergy Supply and Demand
Sustainable Energy: How Much Can We Expect?
Non-Renewable But Very Extensive
Ocean Thermal Electric Conversion
Biomass: Fermentation and Pyrolysis
Drawbacks and Advantages of a Large Energy Budget
Abstract
Appendix on Thermodynamics
In Appendix I, I have tried to provide a brief review of – or introduction to – thermodynamics. Readers will determine the usefulness of my efforts. Many readers will wish to skip this appendix; and, if they are familiar with thermodynamics, they might not miss it. I recommend that everyone read it first however. Alternatively, one might read the words and skip the equations – employing the procedure suggested in the preface. Even the expert might gain an insight or two (or find an error). (However, no one should blame himself if he cannot profit from this attempt to explain thermodynamics in about thirty pages. Undoubtedly, the fault lies with me. In any case, one can render Appendix I completely harmless by simply ignoring it.)
My introduction to Appendix I discusses some suggestions by leading theoreticians concerning the appropriate names we should give to the various divisions of the subject. This brief review doesn’t get beyond the basics of the simplest types of problems. The next main section defines some important concepts, namely, the control volume, what is meant by the properties of a substance and the state of a system. Processes, including cyclic processes, and what is meant by a pure substance and a simple compressible substance are discussed. Next, a generic balance equation is presented, e.g., the increase in the population of the United States is the births minus the deaths plus the immigrants minus the emigrants (during the period of interest). To define work in a slightly novel way, I have defined entropy using a definition of entropy developed by Prof. David Bowman, after which I present the energy balance that represents the First Law of Thermodynamics for the easier cases. (Entropy is defined before energy!) The Second Law is presented as an entropy balance, with the entropy created represented by a thermodynamic-lost-work term, the meaning of which is illustrated by an illuminating example.
The appendix ends by combining the First and Second Laws of Thermodynamics to get definitions of the Gibbs availability function and the Helmholtz availabilty function. These terms are not even in common use, which shows the low esteem in which the concepts are held – even by scientists who ought to know better. I have removed the section in which availability analysis is used to compute the maximum quantity of reversible work that can be performed sustainably within the Earth’s control volume; but, I do present a simple availability analysis to determine the break-even efficiency for burning fossil fuels without emitting CO2. I will present the availability analysis of the entire Earth in a separate paper later.
Main Text
I begin this brief introduction with my chronic complaint that practically every author is calling his propaganda educational whilst I am actually presenting material of an educational nature that is nearly guaranteed to be mistaken for propaganda. (Of course some of it is propaganda, but not all of it is propaganda.) With that off my chest, I begin establishing the need for emergy analysis. Next, I present Odum’s theory of emergy and transformity. When I discuss emergy analysis, I shall employ the rough definition of availability given above. That definition will satisfy some lay people. (Many readers will be satisfied with a qualitative definition and leave the thermodynamics, presented in Appendix I, to experts. One might consult a friend who knows thermodynamics to determine how many mistakes I have made – if any – and whether the mistakes are fatal to my thesis or not.)
Using a departure from Odum’s computation of emergy, I outline my methodology for determining the feasibility of sustainable energy technologies in terms of a modified emergy efficiency that I find satisfactory except that the transformity doesn’t have always a unique value in this new setting. In ecology, nature decides what shall be transformed into what and the pattern is basically immutable. For industrial purposes, the matching problem, i.e., what primary energy resource shall be used for what purpose, is considerably complicated by scarcity and abundance and is by no means God given. This explains why Odum finds transformity so useful in ecology whereas I find it troublesome (to keep track of) in determining the feasibility of sustainable primary energy technologies. I indicate how one might go about determining the primary energy costs, including the indirect costs that are normally overlooked, that go into primary energy production facilities (when the transformities are unknown) using nuclear fission as an example.
In the next section, I use a system diagram approach to model the U.S. or world economy and to speculate on an improved humanistic economy. We then look at energy flows on the earth to estimate how much sustainable energy (availability) we can hope for in the best possible case (short of cold fusion). I speculate that renewable energy from biomass is likely to be the major provider of energy toward the end of the next century. [The reader understands by now that, whenever I use the word energy loosely, I am nearly always referring to high-grade energy, availability, or emergy.]
We, then, look at how energy is likely to be distributed in a one-kilowatt-per-capita, neo-tribal, decentralized society that employs advanced technology in an appropriately humanized manner of which, perhaps, even the Unabomber might approve. The Unabomber confessed that he had been unable to distinguish “good” technology from “bad” technology; therefore, he recommended eliminating all technology – and, just imagine, burning all of the technical literature. I believe I have solved the problem of determining which technologies might be safely retained; and, needless to say, if my system were employed, we could dispense with book burning!
Probably, we can retain (i) technologies that consume only moderate quantities of high-grade energy; (ii) that do not dehumanize anyone; (iii) that can be produced locally in plants small enough to fit in two-car garages, which, clearly, will not be needed for cars; and (iv) that can be understood by the average undiminished user, provided he expend a modicum of effort to understand the world he lives in – quite unlike you and me, who are content to utilize dozens of devices we couldn’t repair if our lives depended on it. Shame on us. With a little more time and effort I might be able to sharpen my characterization of sensible technology – guided by the Schumacherian dictum [2] to behave “as though people mattered”.
Next, we revisit the matching problem for a society in which we have a large menu of sustainable energy technologies to choose from. Finally, we consider under what conditions sustainable energy is likely to be sufficient to permit sustainable happiness – at least absence of unbearable misery – for ten billion people. I draw some conclusions of my own and, then, present a series of extremely important questions that I submit for the reader’s consideration and for further research.
Introduction
Propaganda Is Not Educational
Definition (Education) [from Random House Dictionary (RHD) [3]]. 1. the act or process of imparting or acquiring general knowledge and of developing the powers of reasoning and judgment. 2 - 5. (Irrelevant in the sense of which we are speaking).
Definition (Educational) [from RHD [3]]. 1. pertaining to education. 2. tending or intended to educate, instruct, or inform: an educational TV show.
My claim is that the greater part of this chapter (together with Appendix I, which, in an earlier draft, was part of this chapter) qualifies as educational under any reasonable (dictionary) definition of the word because, first, what I tell you is factual (unless I make an error, which, of course, is always possible despite my best intentions) and is not propaganda or indoctrination; and, second, systems diagrams, emergy analysis, and balance equations, especially availability balances that account for lost work – but really all balance equations – are powerful tools for reasoning and making judgments. (In this draft, balance equations are banished to Appendix I.) All of the material given here and in Appendix I is easily checked, therefore the dangers of unintentional errors are minimized.
This is in contradistinction to many other discussions of the environment (whether pro or con), which are referred to as “educating the public” but amount to nothing better than propaganda. Why must scholars, even successful scholars, abuse the word education so shamelessly?
The lack of understanding exhibited by politicians is appalling; but, it is simply incredible how poorly the subject of this chapter is understood by the “experts” who teach college students, write books, head institutes that collect public funds, express their views on TV, and speak in scientific symposia. As of this writing, I have neither heard nor seen the situation stated at all correctly – present company excepted. I’ve heard and read a lot of nonsense – mostly from people who are “soft” on markets, commerce, and capitalism. I am prepared to refute the conventional wisdom in debate – anytime, any place, and against any odds despite a painful awareness of my own limitations. The reader understands that I have no illusions about the extent of my own mastery of the subject, which I recognize as inadequate. Perhaps, though, I can convince someone that I have made a modest start in the right direction. This is a subject about which practically nothing useful has been said. One should not expect my remarks to be the last word.
Quite distinct from the educational material presented in this chapter is my preference for the soft-energy position in the soft-energy / hard-energy debate, which may be viewed as a matter of personal taste. The consequences of a hard-energy scenario, however, can be derived scientifically; and, I do not see how anyone acquainted with these results could prefer the hard-energy position, which, by the way, is part and parcel of the American Dream.
Why We Need this Chapter
We need this chapter to understand the Environmental Axiom, which is presented in the next chapter. That’s why this is Chapter 2, but excellent reasons can be given for presenting this material even if it were not used elsewhere in the book:
Industrial civilization has been based on fossil fuels. Currently, society is challenged by two opposing trends: (1) fossil fuel is running out and (2) developing nations (and poor people in rich nations) want to live the “American Dream”. Americans have been bingeing on fossil fuel for 150 years – particularly on oil since World War II. We have behaved like the heir who squanders in a day a large fortune built up over dozens of generations. Even conservative analysts such as Wolf Häfele [4] predict severe oil shortages beginning around 2030. The most “optimistic” estimates of total reserves – both discovered and undiscovered – would have us running out in about 400 years at the present rate of consumption assuming (1) no population growth and (2) continued disproportionately low use of oil in the third world. This scenario is in severe conflict with the aspirations of many people. Americans use 25% of the world’s energy budget while comprising only 5% of the world’s population.
Moreover, the American Dream is an environmental nightmare. (This claim is justified somewhat near the end of this chapter when I discuss the unlikely plentiful energy scenario. I should say more about the evils of a highly commercial, consumerist society supported by heavy industry, which, in the usual case, is hard on the environment and, in any case, requires costly measures to prevent serious environmental damage. For now, I shall have to let the Unabomber speak for me despite certain discrepancies in our views. Do not make the mistake of depriving yourself of reading his brilliant Manifesto [5] simply because you don’t approve of his marketing methods. This is one of the best analyses of the harmfulness of heavy industrial technology I have seen. Not reading the Unabomber Manifesto because the author had to kill people to get it published is like not reading Mein Kampf because you don’t approve of the Beer Hall Putsch. Even if it’s wrong, you could save yourself a lot of grief by knowing what it says. (Hitler outlined his plans fairly straightforwardly in Mein Kampf. Why, then, were intellectuals surprised when he began killing Jews? Answer: They didn’t read Mein Kampf!)
Some people (usually not technologists) believe that shortages of fossil fuels will be relieved by technological breakthroughs. It has been noted that these people are like smokers who won’t quit because by the time they get cancer a cure will be found! It has taken nature millions of years to evolve the tree. The likelihood of man developing technology superior to a tree is only slightly greater than the likelihood of developing an artificial human being. Actually, the horrifying plentiful energy scenario (described below) with its excessive motion, alienation, and stress, if not pollution and the wiping out of nearly every species of plant and animal, is unlikely. Nevertheless, reasonable quantities of renewable energy will be needed to support human life. At the present time, as far as I know, despite my involvement with the mainstream scientific and technological sustainable energy communities, I have not heard of anyone who knows, or is trying to find out – even, if any renewable energy technology is feasible.
Normally, when technologists discuss the viability of alternative energy sources, they give us energy costs in cents per kilowatt-hour, for example. But, money is an inappropriate measure to determine which sustainable energy technologies will be feasible. As far as primary energy is concerned, we need the cost in kilowatt-hours per kilowatt-hour produced. Prices are distorted by fossil-fuel subsidies. According to Odum and Odum [6], we purchase the 1700 kilowatt-hours (kWhrs) in a barrel of oil with the money obtained by expending only one-sixth of 1700 kWhrs. Money does not account for the work done by nature; moreover, it does not satisfy useful conservation laws. We need an energy-based measure of value such as emergy – with an m. The Odums claim that nuclear fission and, for that matter, photovoltaic cells are net consumers of energy; i.e., if nuclear fission were the only primary energy source and all of the energy costs of producing it – the direct costs and the indirect costs – had to come from nuclear fission and nowhere else (not fossil fuels), eventually the nuclear plant would grind to a halt because it had not produced enough energy to keep itself going.
We need a methodology that is independent of money for evaluating alternative sustainable energy technologies. Money won’t work (i) because of the distortions in the prices of fossil fuels, (ii) because it can be created too easily by governments, for example, and (iii) because money-based economic theories do not account for the work done by nature. In this essay, we use emergy analysis (1) to assign an immutable measure of value to manufactured articles, capital goods, and energy sources; (2) to understand the economic “facts of life” that reveal why almost all public policy is irrational; and (3) to determine good policy and provide arguments toward widespread acceptance of reasonable social goals. The Odums and other practitioners of emergy analysis use emergy theory for many other useful applications, especially in the field of ecology [7,8,9,10]. I have applied (and modified) Odum’s methods in a different setting, which is not to say that the Odums have not anticipated my efforts in these areas as well. They are true visionaries.
This, then, is an attempt to establish methodologies to put public policy on a firm scientific basis. Unfortunately, this chapter, with or without Appendix I at the end of the book, is likely to be more demanding of the reader than other chapters in the book. If you find the writing inaccessible, please refer the material to a scientifically inclined friend and try to get a judgment of its validity, after which – hopefully – you can accept (or reject) its conclusions. Do not be too hasty to dismiss my remarks, though, if your scientific friend has a vested interest in the status quo, e.g., is an employee of a U.S. or multi-national corporation. Be especially skeptical if your “friend” dismisses these concerns with a cursory glance at the material and what sounds like a Rush Limbaugh quote.
What We Hope To Accomplish in this Chapter
I hope to show that we consistently underestimate the social changes required to achieve sustainable happiness for all of humanity. We shall consider three cases: (i) the case where our supply of high-grade energy keeps pace (approximately) with population, (ii) the case of scarcity, and (iii) the case of abundance. I hope to use the results of this analysis to convince the reader that the Fundamental Theorem is probably true.
Fundamental Theorem. The complete abandonment of competition for wealth, power (and negotiable influence), and negotiable fame is a necessary and sufficient condition for sustainable happiness for all of humanity – under certain conditions that will be stated later. (Hopefully, these conditions can be satisfied, in which case the theorem can be stated without the proviso.)
I hope to prove this as well as social questions are ever proved, but we shall need the entire book to do so. In this chapter, we shall see one reason for the necessity to abandon materialism and, hopefully, we will get some idea of the sufficiency – although much research needs to be done to determine if we can produce enough sustainable energy to support ten billion people in comfort. (“One can never prove a theorem too many ways – especially when no one believes it.”) The terms sustainable and happiness have definite technical meanings that are close to ordinary usage. When the reader has heard the argument given here he or she might accept the idea that, in all probability, economic growth is inconsistent with sustainability. We need economic shrinkage (probably). Also, the reader should be convinced that using money as the basic unit of economic analysis leads to confusion and poor political decisions. Using emergy leads to clarity and understanding.
An interesting new development has begun in the environmental debate. Some overtly anti-environmental activists have entered the fray despite the unpopularity of overtly anti-environmental statements. What does it mean? (Normally, everyone pays lip service to the environment regardless of his true intentions.) In my opinion, it means that some conservatives are beginning to understand the true picture; namely, if we really want to protect the environment, we will have to abandon the American economic system. These anti-environmental zealots are willing to sacrifice nature, which is real, to an economic system, which is a failed abstraction! These people are talking such madness that they may convince some people who have been neutral to join the environmental movement and to adopt the radical and scientifically sound position advocated in this essay – but at least they are not kidding themselves. They understand that environmentalism means the end of the American way of life.
In the old days, conservatives used to say that, if wealth were divided equally, the average wealth would decline and all of us would be poor – at least by the standards of middle-class Americans. The conservatives are correct. What they do not take into account is that, if we do not divide the wealth equally, those who receive less than the average will live lives of misery or simply perish. The point of this chapter is that, according to our best scientific guess, there is not enough to go around unless the big consumers reduce their consumption drastically. The criterion of successful living is to consume as little as possible! We must construct institutions, indeed a new form of community, that will make this possible.
Hopefully, when you have finished this chapter, you will have a strong grasp of the following notions, i.e., sufficiently strong that the first clever conservative you meet cannot talk you out of what you know:
1. The so-called energy crisis is much worse than our leaders say.
2. The end of the petroleum era is the most awesome deadline facing humanity.
3. When petroleum is scarce, our diesel farm machinery will stop, which could mean starvation for billions – not millions. Conceivably, nine billion people could die of starvation before the year 2100.
4. When the average emergy per capita is no greater than the emergy consumption just sufficient to live without undue misery, sharing wealth equally becomes a moral imperative. Every individual who consumes a modicum of emergy in excess of his fair share will be directly responsible for the deaths of the people who sink below minimum subsistence. The number of people who die depends upon how the deficit incurred by that one person is apportioned among few or many.
Odum’s Theory
Wealth
Material Wealth
Money is not equivalent to material wealth. I can say this 2000 times and every time I say it it will be true. Material wealth consists of the things we need to live, including art to enhance our spiritual lives, and a few luxuries to take the drudgery out of life. It can be measured in units of emergy – with an m. Examples of material wealth are (i) food, (ii) clothing, (iii) housing and other infrastructure, (iv) tools and other capital goods (things used to make other things), (v) medicine and drugs, (vii) stockpiles of high-grade energy, (viii) works of art, (ix) books, (x) computer programs, (xi) correct, useful, and non-trivial information, etc.
Spiritual Wealth
Naturally, the wealth of the intellect in its vast accumulations of knowledge and mental powers, the wealth of the psyche in its deep understanding and love, and other forms of spiritual wealth are not what we are referring to in our discussion of the evils of inequality of wealth. Indeed, by eliminating differences in material wealth, we hope to make greater spiritual wealth, consistent with one’s capacity, available to everyone. This is why it is so difficult to distinguish one’s final goals. Every goal can be a means to something more and every intermediary stage is someone’s personal goal. These intermediary stages can be taken to be the means to an end by someone else. Thus, Popper’s thesis in “Utopia and Violence” [11] is untenable. He imagines that one can distinguish means from ends, which is impossible. (“Utopia and Violence” was discussed at the end of Chapter 1.)
Money and Other Forms of Surrogate or Paper Wealth
When I speak of surrogate or paper wealth nowadays, I may be talking about entries in computer files. Sometimes there is no paper involved, but the dynamics are the same whether it be paper money, stock and bond certificates and other fiduciary instruments, or simply entries in a computer, e.g., John Doe owns 100 shares of General Motors. Paper wealth is not considered wealth in this theory, despite the terminology. However, as long as people have faith in it, it is a surrogate for real wealth, which means it can be converted into real wealth.
Paper wealth, which is normally negotiable, has brought down empires. It can be accumulated without owning a treasure chest – let alone a storehouse for wheat, cotton, lumber, and drugs. Large differences in paper wealth between citizens who own comparably sized homes can occur. Paper wealth can create massive poverty and it can mask serious underlying difficulties in an economy that is not producing food, clothing, and shelter in adequate amounts. The exact way in which catastrophes occur because of such vast accumulations might be extremely complex. On the other hand, it may be no more difficult to comprehend than our own recent savings and loan debacle. Permit me to describe an imaginary simplified scenario that indicates the type of thing that can happen.
The Fall of the Paper Empire
The claim is that an empire or nation can fall because of large accumulations of paper wealth in the hands of a few individuals – less than 1% of the population, say. The best I can come up with is a thought experiment where this happens. I leave it to the reader to decide whether or not the following scenario is plausible. This point is not crucial to my thesis and I do not absolutely insist upon it.
Ground rules
This is supposed to be a hypothetical society the needs of which are few. The people eat food produced domestically by about 1% of their population, but they do not require dwelling places or health care. The fuel for their cars, trucks, trains, boats, and planes is processed practically automatically from imported crude oil. Their communication is done using amazingly high-tech imported gadgets that practically run themselves. Indeed, everything they need except food is produced abroad and they consume all of the food produced by the tiny minority engaged in that once-noble pursuit, who now eke out a bare existence on practically the lowest level of the social ladder. After all, every adult who does not produce food is a college graduate, normally with a masters degree in something – usually some highly specialized aspect of commerce – The Art of the Deal or something even deeper!?
The accumulation of paper wealth (freely convertible to old man’s toys until the pyramid crashes) comes from business done in connection with foreign trade and the sale and distribution of foreign goods, including primary energy, e.g., petroleum, to domestic customers most of whom are employed in (i) negotiating deals, (ii) selling the goods at the wholesale, retail, and street level (mostly to each other), (iii) marketing, (iv) the government, (v) personal-salvationism; i.e., they are spiritual counselors, lawyers, consultants, presenters of seminars on (a) how to manage people, (b) how to comply with the new government regulations, (c) how to succeed in business without really trying, and (d) how to lose weight while eating as much as you want and never exercising, (vi) managing any of the above. These are a sorry crew. They produce not one single thing that anyone needs to live. They call their society THE INFORMATION SOCIETY, but they might just as well call it the paper money society. [To call what they know information is to call excrement food.]
To show you how simple (and therefore amenable to analysis) this hypothetical society is, I shall divide it into four sectors and four classes. The sectors are (i) business, government, and academia, (ii) service, and (iii) agriculture. Please forgive me for lumping business, government, and academia together; but, really, they are barely distinguishable from one another. It’s easy to distinguish them from service, though, because the service sector pays minimum wage. Agriculture depends on the market, however, so prices are high whenever crops fail, i.e., when there is nothing to sell. If it weren’t for government subsidies, the members of the agriculture sector would make less than minimum wage!
I have saved the fourth sector for last. It is, of course, the military. It is difficult to live off the efforts of the citizens of other nations and their natural resources without a military sector. They enforce business contracts negotiated by men and women who couldn’t pass basic training if their lives depended on it. In other words, the army, navy, air force, and marines “persuade” the trading partners to accept paper currency in exchange for real wealth. This is what petty hustlers and crooks call “a real sweet deal”.
The four classes, then, are (i) white collar criminals and tyrants, (ii) their lackeys, (iii) military personnel, who, with the exception of a handful of lunatics, would not work without pay (but will do anything for a price) and have no interest whatever in the agendas of those who pay them, and (iv) dropouts (usually heavy drug users, artists, and philosophers), the homeless, the hopelessly handicapped and deficient, the elderly, the terminally ill, and people who are kept around, mostly in jails, in case someone of consequence needs a spare part, etc.
What Goes Wrong
1. The agriculture sector must suffer economically so that the rest can eat. Moreover, they tend to be social pariahs and, by induction, so do their children. They resent this and their children refuse to enter the field; moreover, they begin to sell their farms to housing and business developers. Pretty soon some of the food has to be imported.
2. Business and government begin to eliminate middle management and appropriate more and more unto fewer and fewer.
3. The military can barely be paid (the interest on the national debt is staggering) and soon the nation is scarcely able to defend its “vital interests”. Soldiers grumble and desertions start. Also, contrastingly, people who are less willing and less able to fight want to become a part of the military because things are worse elsewhere.
4. In emulation of business, many of the lower paid workers, usually in the service sector, and many of the disenfranchised resort to crime and violence where a few opportunities to become wealthy through drug sales, say, still exist. Soon, enough of these disillusioned people become politicized and organized terrorism begins. The military and police are practically powerless. (The police are outgunned!)
5. The small professional class (not mentioned separately above) is infiltrated by foreigners who nucleate, e.g., hire only people of the same nationality as themselves, and soon control entire areas of expertise. These foreigners have been brought in by predatory businessmen to keep the wages of their lackeys low. Eventually, the lackeys of the tyrants and businessmen are reduced to wage slavery. Natives are no longer attracted to the professions and attempt to become businessmen themselves rather than lackeys. This is a big drain on professional talent. Some of the most gifted people begin to plan a revolution.
6. The rest of the world is loath to accept devalued paper money and the supply of oil and manufactured goods begins to slow down.
7. Agriculture no longer can feed everyone because it is entirely dependent on foreign oil and machinery.
8. Rebellion begins in the military and spreads rapidly. Some military remain loyal to business and the most powerful elected officials and bureaucrats, so civil war spreads throughout the land – mostly in the cities.
9. Resentment of foreigners escalates essentially to pogroms. The foreigners fight back, quickly organizing into “benevolent societies” and “tongs”.
10. Alienation, anomie, and dissolution of all social order is complete.
11. The Four Horsemen saddle up and ride.
Emergy (with an M)
Definitions
Definition (Availability). Availability (or available energy) is energy [enthalpy, H, or internal energy, U] corrected for entropy, S. Rigorous definitions of the Gibbs availability function [H – ToS], the Helmholtz availability function [U - ToS], and entropy are given in Appendix I, Fundamentals of Thermodynamics, where the symbols and technical terms employed in this paragraph are explained. [To is the temperature of the environment, usually taken to be the temperature of the coldest body of water or the atmosphere into which the waste heat of a heat engine can be discharged. For Earth, 300 K will do. The effect of entropy on the availability function of sunlight is to reduce it by the ratio of the temperature of Earth to the temperature of the Sun – a factor of about 19/20. Since the enthalpy of a proton is 4/3 times the energy, the Gibbs availability of sunlight is about 76/60 times the energy.] The reader understands that by the word “energy”, as it is used in ordinary parlance, we mean availability.
Definition (Exergy) [1]. In an environment whose ambient temperature and pressure are known, such as the atmosphere or a large body of water, exergy, with an x, is an exact measure of the maximum reversible work that can be obtained from a fixed quantity of material, such as a fuel, the sole use of which is to supply available energy to a process under investigation. We define the exergy per fixed quantity of material to be the difference between the Gibbs availability of the material and the Gibbs availabilty of the same quantity of the same material reduced to ambient temperature and pressure (generally lower) and, especially in the case of fuels, brought into chemical equilibrium with the surroundings by reacting chemically to obtain products from which no additional work can be extracted. In this treatment, I shall neglect any additional work that might be extracted by allowing combustion products, for example, to diffuse from their high concentration in the combustion chamber to the concentration at which they are found in the atmosphere far from the site of the combustion.
Thus, the exergy of one kilogram-mole of octane at 500°C and 10 atmospheres is the difference between the Gibbs availability of 114 kilograms (one kilogram-mole) of octane (the fuel) at 500°C and 10 atmospheres minus the sum of the Gibbs availability of 352 kilograms of carbon dioxide and the Gibbs availability of 162 kilograms of water (the products of combustion) all at 300 K and one atmosphere. This is the most degenerate state that this collection of atoms can attain in a world where temperatures lower than 300 K and pressures lower than one atmosphere cannot be found except by actually doing work, which would defeat our purpose, namely, to discover the maximum amount of reversible work that we can extract from the 114 kilograms of octane at elevated temperature and pressure. We are assuming here that 400 kilograms of oxygen is obtained from the ambient air and that it does not contribute additional availability; i.e., its exergy is zero – just as its Gibbs availability, which is equal to the Gibbs free energy at atmospheric conditions, is zero. As stated above, we are neglecting any possible work that might be extracted from the high concentration of carbon dioxide and water vapor just after combustion by allowing it to diffuse (through some sort of machine) to the average (low) concentration of carbon dioxide and water vapor normally found in the atmosphere. (Presumably, we could invent some sort of device that would harness the differences in partial pressures using a semi-permeable membrane, say.)
Odum’s original definition of emergy. Odum defined emergy, measured in emjoules, to be the Gibbs availability of the sunlight, measured in joules, required to produce, by an optimal process, (1) fuels; (2) other energy sources such as wind or fresh water in mountain lakes; (3) natural resources such as grass and trees, (4) manufactured objects, (5) human resources; (6) information; and (7) any other objects of economic interest that can be associated with an identifiable quantity of sunlight. This is a sunlight-based emergy. It leads to large numbers for the emergies of primary fuels that are known only approximately; therefore, we shall modify the definition slightly to give common industrial energy products emergies that are known precisely and that are close to 1.0 in magnitude.
|
Table 2-1. Solar Transformities (solar emjoules per joule) [7] |
|
|
Item |
sej/J |
|
Sunlight |
1 |
|
Wind kinetic energy |
623 |
|
Unconsolidated organic matter |
4,420 |
|
Geopotential energy in dispersed rain |
8,888 |
|
Chemical energy in dispersed rain |
15,423 |
|
Geopotential energy in rivers |
23,564 |
|
Chemical energy in rivers |
41,000 |
|
Mechanical energy in waves and tides |
17,000-29,000 |
|
Consolidated fuels |
18,000-40,000 |
|
Food, greens, grains, staples |
24,000-200,000 |
|
Protein foods |
1,000,000-4,000,000 |
|
Human services |
80,000-5,000,000,000 |
|
Information |
10,000-10,000,000,000,000+ |
The transformity of sunlight is, of course, unity. The entry for wind kinetic energy says that 623 joules of sunlight are required to generate 1 joule of kinetic energy in wind. (Wind has about 40 joules of thermal energy, which is not available to us, per joule of kinetic energy.) Each joule of geopotential energy in dispersed rain requires 8,888 joules of sunlight according to Odum. Presumably, some portion of this falls into mountain lakes, etc., which, in turn, feed mountain streams and rivers and may be used to produce hydroelectric power. The entry for geopotential energy in rivers is 23,564. (How it can be known to five significant figures I cannot say.) The emergies of food, greens, grains, and staples must account for the rain they require, the sunlight they absorb in photosynthesis, any fossil fuel that is used in their cultivation and transportation, etc. Each joule (of availability) such foods contain requires from 24,000 to 200,000 joules of sunlight – depending, I suppose, on whether they grow wild in the consumers backyard or are farmed by a giant agri-business and shipped half way around the world. The reader realizes that a meal of greens from the green grocer, which might contain 21 million joules of Gibbs availability, has an emergy that might be as high as 4.2 trillion solar emjoules. The case of human labor is interesting too. I consume energy at the rate of about 0.1 kilowatts when I work. That’s 100 joules per second. If I work one hour using all of the knowledge I have acquired through some very expensive (no doubt overpriced) schooling, the emergy cost of that hour could be as high as 5 E9 solar emjoules per joule times 3600 seconds per hour times 100 joules per second times 1 hour = 1.8 E15 solar emjoules. (That’s 1.8 million billion emjoules.) So, these are some pretty expensive words you are reading!
Sunlight-based emergies have the disadvantage that they are large and known only very roughly. Moreover, gross estimates are used to evaluate the fuels we use most frequently. We don’t know how many joules of sunlight must be expended by the most efficient process to produce one joule of alcohol from biomass. Undoubtedly, the optimal process has yet to be discovered. These are deficiencies in emergy analysis. They can be remedied somewhat as will be shown. Howard Odum recognized that the value of manufactured goods can be quantified in terms of the energy consumed to produce them. What we owe to the genius of Howard Odum is beyond our powers to compute (even in units of emjoules) – it is truly priceless. That said, I must warn the reader that the use to which I put his gift is my responsibility alone. If my implementation of his ideas, which, for the most part, corresponds to my personal taste and inclinations, turns out to be defective, the blame lies solely with myself and does not reflect upon the merit of his original conception and the great body of his vast and rapidly growing scientific legacy.
If we wish to do economics based upon emergy, we need to assign emergies to capital goods and other manufactured objects. Let us see how to do this in a thought experiment involving an imaginary ideal process. In this process, the only input is energy (availability); no raw materials are used or, put another way, the raw materials are not considered to have any value – maybe negative value – like toxic waste or raw sewage, but we won’t take credit for it. The process produces one product. We wish to compute the emergy of that product produced by an optimal process.
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Figure 2-1a. Energy balance for ideal process |
Figure 2-1b. Availability balance for ideal process |
Figure 2-1c. Emergy balance for ideal process |
In Fig. 2-1a, we depict the energy balance for our process. We don’t show the product coming out, which is assumed to carry negligible energy. All of the energy entering is reduced to junk heat. In Fig. 2‑1b, availability enters and nothing comes out, since junk heat has no availability (in this analysis) and neither does the product, which can’t even be burned. The lost work term provides closure for the availability balance. Finally, in Fig. 2-1c, the emergy balance is shown with the transformed availability entering, measured as emergy, and the product carrying an equal amount of emergy along with it into the economy – even though all of the availability was consumed as junk heat.
In the case of a similar process that produces the same unit product but is less than optimal, more emergy is required at the input, and the difference between the input and the output is lost. Thus, as in the Combined First and Second Law (Appendix I, Eq. I-6), emergy can be destroyed.
In their earlier work [6], Howard and Elizabeth Odum measured emergy in fossil-fuel equivalents. Emergies used to evaluate industrial economies might be computed more easily by taking the transformity of crude oil or even methane as unity. If we are moving toward an electrical basis for energy analysis, it might be better to take one joule of single-phase, 60 cycle (Hz), 110-volt alternating current (AC) as the unit of emergy – or, perhaps even better, 3,600,000 joules ( = 1 kWhr).
Definition (Standard Electricity). In this paper, single-phase, 60 Hz, 110-volt alternating current is taken to be standard electricity.
Definition (Emergy Unit). My arbitrary – but well-defined – choice for one unit of emergy (1 MU) is 1.0 kilowatt-hours of standard electricity. Although electrical current carries a small amount of entropy manifest in difference currents, for all practical purposes, that is, for engineering purposes, electricity is pure work. The availability of electricity is equal to its energy; and, with this choice of emergy unit, the emergy of electrical current is numerically equal to its energy in kilowatt-hours. The transformity of sunlight, wind, biomass, and other energy products will be less than – but close to – 1.0.
Definition (Transformity). The transformity of a primary fuel is the number of kilowatt-hours of standard electricity one can obtain from 1 kWhr of the primary fuel by an efficient process, the tradition of reporting the availability of fuels in BTUs per pound or kilocalories per gram mole notwithstanding. Any unit of energy can be converted to kilowatt-hours. This is an electricity-based transformity, the units of which are emergy units per kilowatt-hour.
Definition (Emergy). The embodied energy or emergy of a primary fuel is the Gibbs availability of the fuel in kilowatt-hours multiplied by the electricity-based transformity. The emergy of anything else is the sum of all the emergy that went into producing it by an efficient process minus the emergies of any by-products formed. The emergy of an activity is the average rate of expenditure of emergy times the time. These definitions are easily extended to include the dependence of emergy on location and time. The concept of nemergy or negative emergy can be introduced to aid in the discussion of environmental damage.
Definition (Emergy efficiency). Emergy efficiency is emergy out divided by emergy in. This efficiency is 1.0 for an optimal process because the emergy of the output is defined to be the emergy of the inputs. For a less than optimal process, the emergy efficiency is the emergy of the inputs to an optimal process over the emergy of the inputs to the process under investigation. Emergy efficiency lies between zero and one.
The transformity of any fuel can be determined by using it to generate standard electricity by an efficient process. The most efficient process might be a fuel cell. Therefore, the emergy of any fuel is the Gibbs availability of the fuel multiplied by the electricity-based transformity.
Balance Equations. Sholto Maud suggested working out energy, availability, and emergy balance equations for simple extraction and conversion processes. Writing balance equations for extraction and Type 1 conversion helped me to understand what must be included in the definition of emergy and what may not be included without encountering inconsistencies. Many other people can improve their understandings by studying the balance equations discussed at http://www.dematerialism.net/Mark-II-Balance.html.
Extraction. An example of extraction is the production of petroleum from the well to the refinery. Extraction is discussed in http://www.dematerialism.net/Mark-II-EROI.html.
Type 1 Conversion. The first type of conversion is the production of primary energy from energy supplied by Nature for which we do not compensate Nature. This is a sustainable process provided the energy from Nature (natural energy) comes from a source that is continuously renewed by the Moon or by the Sun shining on the Earth. The input to such a process includes other types of energy, material goods, transportation, labor, taxes, etc. The output includes the principal product, by-products, waste heat, and pollution. Normally, pollution is not considered; however, the concept of nemergy (negative emergy) should be employed to account for pollution of every type even, for example, the extent to which animals are deprived of habitat by the mere existence of the energy production facility. Examples of Type 1 conversion are the production of electricity by windpower and solar power. The emergy balance equation for a Type 1 process is illustrated in Figure 2-1d:
Figure 2-1d. Emergy Balance for Type 1 Conversion
Let us define some symbols to be used in connection with Figure 2-2:
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Table 2-2. Symbols used in this discussion |
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ER |
Gibbs availability of fuel produced by process |
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λR |
electricity-based transformity of fuel produced |
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MR |
emergy of fuel produced by process = λR · ER |
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MI |
the algebraic sum of all of the emergy inputs (except for MN) minus the by-products |
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EI |
Gibbs availability of stream MI |
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μ |
ratio of EN per unit mass to ER per unit mass |
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EN |
Gibbs availability of energy from Nature = μ · (ER + EI) |
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λN |
the electricity-based transformity of the energy supplied by Nature |
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MN |
emergy of energy from Nature = λN · EN |
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β |
Energy returned over energy invested (EROI) = ER/EI = MR/MI |
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EP |
the Gibbs availability of primary energy in Type 2 conversions |
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λP |
the transformity of the primary energy source in Type 2 conversions |
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MP |
the emergy of the primary energy supply in Type 2 conversions |
Each of the input emergies, except the emergy supplied by Nature, is to be transformed into a product-equivalent emergy. Then, the emergy invested, MI, is imagined to have been produced by the same process that produced the fuel. In this way, it will be apparent immediately if the process consumes more emergy than it produces. All indirect energy expenses should be included in the MI term, in which case EROI is a good measure of the effectiveness of the process. (See http://www.dematerialism.net/Mark-II-EROI.html.) [An example of an indirect cost is the pro-rata share of the commuting costs of the tax consultant (A) that should be charged to the worker (B) who maintains a windpower installation because the man (C) who serves B lunch had his taxes done by A.]
Then, since
and,
In the first approach, the transformity of the product is determined by the generation of standard electricity with a well-known, efficient process and the transformity of the energy from Nature, whether it be from the tides, from biomass, from wind, from sunlight itself, or from some other natural source, is determined from the emergy balance. Normally, this transformity is well established. Therefore, two separate cases obtain:
Case 1. If λN, the value we compute, is greater than λN*, the accepted value of the transformity of the natural energy, then we should report that our process is part of a more efficient route to standard electricity, and λN should be considered for a new value of the transformity of the energy supplied by Nature.
Case 2. If λN is less than λN*, then our process is less efficient than the process that established the larger value and we must report an emergy efficiency, η, for our process because we could have generated more emergy with the same quantity of natural energy if we had used the standard process. The reader should remember that the energy from Nature is “free”, but the area of the solar collector or the size of the windmill is not.
In the second approach, the well-established value of the transformity of the energy supplied by Nature is accepted and the transformity of the product is computed from it. Call it λR'. If λR' is less than λR, the true value, we should revert to Case 1 and recalculate the transformity of the natural energy. If λR' is greater than λR, then the efficiency is λR over λR'. This is in agreement with Equation 2 above.
Let us imagine the process in the configuration illustrated by Figure 2-1e.
Figure 2-1e. Alternative Diagram for Type 1 Conversion
If the algebraic sum of the emergy inputs to a process minus the emergy supplied by Nature exceeds the emergy of the product, that is, if MI > MR, then the process is wasting energy resources. This is the case for some alternative energy projects that seek venture capital, government subsidies, donations, or unwary buyers. If they were not subsidized by fossil fuel, they would not work.
Type 2 Conversion. The second type of conversion is the production of secondary energy from primary energy. The production of hydrogen from methane or from electrolysis of water is an example of Type 2 conversion. Figure 2-1f is the same as Figure 2-1d except that MP, the primary energy, is substituted for MN:
Figure 2-1f. Emergy Balance for Type 2 Conversion
In the first approach, the transformity of the product is determined by the generation of standard electricity by a well-known, efficient process and the transformity of the primary energy is computed from the emergy balance equation just as we did in the case of a Type 1 conversion, mutatis mutandis:
Case 1. If λP, the value we compute, is greater than λP*, the accepted value of the transformity of the primary energy, then we should report that our process is part of a more efficient route to standard electricity, and λP should be considered for a new value of the transformity of the primary energy.
Case 2. If λP is less than λP*, then our process is less efficient than the process that established the larger value and we must report an emergy efficiency, η, for our process because we could have generated more emergy with the same quantity of primary energy if we had used the standard process.
In the second approach, the well-established value of the transformity of the primary energy is accepted and the transformity of the product is computed from it. Call it λR'. If λR' is less than λR, the true value, we should revert to Case 1 and recalculate the transformity of the natural energy. If λR' is greater than λR, then the emergy efficiency is λR over λR'. This is in agreement with Equation 3 above. These results are worth deriving in a different way:
If a fuel the emergy of which is known is produced by the process under investigation and the sum of all of the emergy costs – both direct and indirect – that go into the process (computed with the true transformity λP*) minus the emergies of any useful by-products is greater than the algebraic sum of the emergy inputs for the process that determined the known emergy of the energy product, the process under investigation is sub-optimal and the emergy efficiency, η, is
and, the transformity of the product we would compute from
is higher than the true value λR. The only justification for the process is that we cannot do without the product and there is no other way to get it, which is not the case when electricity is used to produce hot water (discussed below) since hot water can be produced with less emergy by burning fuel under normal circumstances. Nevertheless, the process may be needed in extraordinary circumstances where the burning of fuel is prohibited, e. g., on a space satellite.
If the algebraic sum of the emergy inputs for the process under investigation is less than that of the older process, the transformity of the primary energy should be recalculated. It may not be expedient to discontinue production by the older process immediately because of compelling reasons not to shut down the older facilities – not the least of which is the time delay before new facilities can be built. The emergy efficiency of the older process is now less than 1.0.
Type 3 Conversion. The third type of conversion is the manufacture of non-energy goods. The manufacturing process has inputs of energy, material goods, transportation, labor, taxes, etc., and outputs that include a principal product, by-products, and waste heat. This is best illustrated with a diagram such as Figure 2-1g.
Figure 2-1g. Emergy Balance for Manufacturing Process
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Table 2-3. Symbols for Figure 4 |
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MI |
emergy of direct energy supplies |
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MX |
emergy of inputs of material, transportation, labor, taxes, etc. |
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MA |
emergy of principal product |
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MB |
emergy of by-product |
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MW |
emergy of waste heat stream |
The emergy, MW, of the waste heat stream is its availability times the number of kilowatts of standard electricity that can be generated efficiently by one kilowatt-hour of waste heat. The emergy of the sum total of all direct energy inputs to the process is determined in the usual way. The emergy of the sum total of all non-energy inputs must be available from past studies or must be determined during the analysis. It may include contributions from pollution etc. in which case negative emergy in the output is added to the input. Unlike the case of energy production, the transformities of the inputs cannot be influenced by the process. The emergy of the principal product and the by-product must equal the emergy of the inputs minus the emergy of the waste heat. In the case of a principal product as the sole output, the determination is trivial. However, when one or more by-products are present, the emergies of the by-products and the principal project must be apportioned in a canonical manner that should be determined by the analyst on a case-by-case basis.
If the emergy of a by-product is known in some other way, it may be appropriate to use the known value. In a case where the emergies must be distributed equitably, the relation between market price, either instantaneous or averaged over time, and energy or emergy may be useful. See “The Relation of Energy to Money”. Thus, the emergy is apportioned according to market value. This is a singular intrusion of money into the physical realm of emergy analysis and may not be advisable. In a non-market economy, some combination of energy, labor, capital expenditures, product mass or heat of fusion (even) might be of use. In any case, the sum of the emergies of the products must close the emergy balance. The consumer may find it expedient to compare the emergy of any given product with the emergy of a comparable product to minimize his impact upon the environment.
Note. The EROI defined in this essay is sometimes denoted EROI-1 because it is one less than the usual EROI which equals (MR + MI)/MI. The reader should realize that the terms Type 1, Type 2, and Type 3 Conversion have no currency outside of this essay.
Matching Problems
At this late date, we still have no idea if even one sustainable primary energy technology exists other than firewood itself. (We would prefer not to burn firewood directly, because of the smoke, even if it turns out that global warming (from carbon dioxide) is not a problem.) In any case, when we analyze our first sustainable energy process, we have no right to imagine that a less expensive sustainable energy source exists that can be “matched” to that process. We cannot make use of predictions concerning the distribution and usefulness of our form of primary energy (call it Eo) or any other. In other words, we must do our determination of feasibility with only occasional reference to the matching problem that will be solved subsequently.
Thus, it is, in fact, Eo, itself, that must carry the burden of the direct and indirect costs with few exceptions. If we have sustainable electricity, probably we would use electric cars, which are much more efficient consumers than gasoline or diesel cars, regardless of the emergy costs associated with building the cars and providing the electricity. Workers commuting back and forth to work will consume about one-third the energy budget of a gasoline-powered car. We do not use electric cars currently because, with 1997 technology, we would consume more fossil fuel making electricity for electric cars than gasoline cars consume on the road. [A good case can be made that the reason we do not use electric cars in 1997 is that oil companies have conspired to prevent us from doing so, but it is not necessary to make so reckless an accusation to advance the thesis of this essay. This book is about radical social change. It is singularly lacking in sensational conspiracies.] It takes about three kilowatt-hours of fossil fuel to produce one kilowatt-hour of electricity in a modern power plant even with cogeneration. Thus, one-third (of the energy consumption of a comparable gasoline-powered car) is the break-even point for cars powered by electricity from power plants – not that we wish to use fossil fuel even when we can use less of it than the comparable budget for sustainable forms of energy. [Probably, in an economy whose only primary energy is electricity, hydrogen from electrolysis of water would be the fuel of choice (or the precursor of the fuel of choice) for applications that cannot use electricity.]
Examples
Consider Process A, which produces a continuous stream of hot water at 500 K. The inputs to Process A are cold water, whose Gibbs availability may be taken to be zero, and 1 kilowatt of 110-volt, 60-Hz AC. Since electricity can be converted to work with an efficiency close to 1.0, we set the power term in the rate form of the energy balance equation to precisely 1 kilowatt. It may be used to lift a weight or it may be converted to heat completely. Let us divide Process A into two control volumes to facilitate analysis. The first control volume, A1, consists of an ideal electric heater. The energy balance equation, presented in Appendix I, is
It is easy to see from Eq. I-1 that, for A1, which is a steady-state system, Qout = Win, or, in terms of rates,
Next, consider a control volume, A2, consisting of the space within Process A through which the water flows. The inputs to Process A2 are cold water with zero availability and the heat from the electric heater, which for the water should be written Qin. The output is hot water at 500 K. To see that the availability of the hot water is the output of a Carnot engine the high temperature reservoir of which is the hot water and the low temperature reservoir of which is cold water at 300 K, we write the Availability Balance (Combined First and Second Laws) for Process A2. The Availability Balance Equation is
or in rate form
where, for a steady-state process, the term to the left of the equal sign is zero; and, for a reversible process, the rate of lost work term is zero. Moreover, the availability of the water entering is zero, the heat out is zero, and both work terms vanish to give
This shows that the Gibbs availability of the hot water is equal to the exergy. (To find the exergy for fuels one must subtract the Gibbs availability of the combustion products from the Gibbs availability of the fuel.) If, instead, we had transformed the availability of the hot water to standard electricity, we would not have been able to do it with anything like the efficiency of a Carnot engine. Perhaps we would have been able to obtain 0.2 kilowatts, i.e., one half of the Carnot efficiency, which is rather optimistic.
Suppose we wish to produce standard electricity (call it Eo) by means of photovoltaic cells. One emergy unit then is one kilowatt-hour of Eo. An emergy flow diagram for this thought experiment appears in Figure 2-2 below. Since, ultimately, we must determine if this technology is feasible or not, we will assume that Eo is the only form of primary energy available. Therefore, we will employ this form of energy for most of our production needs. Moreover, we must assume that the suppliers of goods and services will employ our product as well. Also, most suppliers have some known emergy costs associated with manufactured items – from paper clips to electron scanning microscopes. Since the emergies are known, either because Eo has been used always or because it is easy to convert the emergies to what they would be if Eo were used, no further emergy analysis is required. Let us denote these emergies Cn, where it is understood that Cn will take different values depending on where the symbol appears. Some of the emergy inputs are not even labeled; i.e.,