Energy: Science, Policy, and the Pursuit of Sustainability
208
Energy: Science, Policy, and the Pursuit of Sustainability
208Overview
In the early 2000s, energy prices have fluctuated wildly, from historic highs in the winter and spring of 2001 to the lowest wholesale prices in decades a few short months later. As the largest user of fossil-fuel energy, the United States is the key player in the world's energy markets, and our nation's energy policy (or lack thereof) has become a subject of increasing concern.
Energy: Science, Policy, and the Pursuit of Sustainability is an essential primer on energy, society, and the environment. It offers an accessible introduction to the "energy problem" -- its definition, analysis, and policy implications. Current patterns of energy use are without question unsustainable over the long term, and our dependence on fossil fuels raises crucial questions of security and self-sufficiency. This volume addresses those questions by examining the three broad dimensions of the issue: physical, human, and political-economic. Chapters consider:
- the laws of nature and the impacts of energy use on our physical and ecological life-support systems
- the psychological, social, and cultural factors that determine how we use energy
- the role of government actions in adjusting costs, influencing resource consumption, and protecting the environment
- how markets work, and the reasons and cures for market failures in responding to long-term environmental and energy problems
Product Details
| ISBN-13: | 9781597262484 |
|---|---|
| Publisher: | Island Press |
| Publication date: | 02/22/2013 |
| Sold by: | Barnes & Noble |
| Format: | eBook |
| Pages: | 208 |
| File size: | 15 MB |
| Note: | This product may take a few minutes to download. |
About the Author
Robert Bent is professor emeritus of physics, and Randall Baker is professor of public and environmental affairs, and Lloyd Orr is professor emeritus of economics, at Indiana University.
Read an Excerpt
Energy
Science, Policy, and the Pursuit of Sustainability
By Lloyd Orr, Robert Bent, Randall Baker
ISLAND PRESS
Copyright © 2002 Island PressAll rights reserved.
ISBN: 978-1-59726-248-4
CHAPTER 1
Rules of the Game
ROBERT BENT, ANDREW BACHER, AND IAN THOMAS
* * *
We begin with the "rules of the game"—the fundamental laws of nature that govern all energy transformations. Understanding these laws is crucial to achieving sustainability—-nature cannot be fooled! The two most important natural laws governing energy transformations are known in science as the first and second laws of thermodynamics, and they have profound implications regarding the sustainable use of finite energy resources. We also consider in Chapter 1 the implications of steady growth in world energy use, in particular so-called exponential growth (constant percentage growth per year) in a solar system of finite energy resources. This is not sustainable. These basic principles underlie everything else in the book.
—Editors' note
* * *
Scientific theories are often expressed in terms of "laws of nature" that describe how the world works. Although new research continues to provide scientists with a deeper understanding of the universe and occasionally forces them to modify their theories, the laws of nature are absolute laws—they cannot be changed or circumvented by human ingenuity or by technological advances. In this sense, they are the rules of the game—the "game" of human survival and well-being. We have no choice but to obey these rules, so we must strive to understand them and to find ways to live in harmony with them.
Scientists have elaborated the laws of nature as they pertain to energy. The first of these is known as the first law of thermodynamics. It asserts that although energy can be converted from one form to another, the total amount of energy in all forms stays the same (is conserved) in all physical processes—energy is never created or destroyed. This is also known as the principle of conservation of energy. A naive interpretation of the first law might lead one to conclude that, since energy is never destroyed, there is no energy crisis and we have nothing to worry about. However, as we explain later, the situation is not so simple as that. Although energy is never destroyed, some energy is dissipated—degraded into a less useful, lower-grade form—during every energy conversion. Because energy is dissipated in all interactions, and because it is essentially impossible to convert low-grade energy back into a useful, high-grade form, the total amount of useful energy in the universe is continually declining. This universal trend is equivalent to a transition from a state of order to a state of disorder—also known as the law of entropy—and is mandated by the laws of probability, specifically by the second law of thermodynamics. Put another way, a "disordered" universe is far more probable than an "ordered" one, so there is an irreversible tendency toward a disordered universe full of useless, low-grade energy.
According to our scientific theories, then, all useful energy will eventually be used up. However, the time scale for the degradation of all of the energy in the universe is immense and, in the meantime, the earth receives an abundance of useful, high-grade energy from the sun. Humans could, theoretically speaking, survive on this planet for billions of years to come by learning how to rely on the sun's energy as other earthly life forms do. However, we are running out of time to make the transition from the depletable stocks of energy sequestered over geologic eras within the earth to a reliance on the flow of energy from the sun—the ultimate source of so-called renewable energy. If we do not act reasonably soon, this inevitable transition is likely to cause immense human suffering.
In the final section of this chapter, we discuss the nature and implications of exponential (constant percentage) growth, the conflict between this kind of physical growth and sustainability, and the need to understand the arithmetic of exponential growth in order to anticipate and prepare for limits to steady growth of this kind in world population and resource consumption.
The possibility of new energy sources on earth that we are not using today is discussed in Appendix 1. Energy units, factors for converting one unit to another, and a graphical comparison of unit sizes are given in Appendix 2.
What Is Energy?
Everything that happens in the universe involves a flow and transformation of energy. Whenever a living thing or an inanimate object experiences any kind of change, energy moves from one place to another and changes form. But what is energy?
A popular (and quite accurate) conception of energy is that it is a resource that makes life easier for us—a resource that takes us from one place to another, provides heat and light, powers our entertainment devices and laborsaving appliances, and improves our quality of life. The development of energy technologies began in the middle of the eighteenth century with the Industrial Revolution, which resulted in a steadily increasing usage of energy—mainly from fossil fuels—in industry, commerce, agriculture, transportation, and the home. This in turn resulted in the steadily increasing productivity that is such a desired feature of modern economies. Two and a half centuries later, human beings are now prodigious users of energy compared to other species, using ten to a hundred times as much as is needed for biological survival.
Even though people know roughly what they mean when they talk about energy, there has always been something a little mysterious about it. It is an abstract quantity, an attribute or property of matter that cannot be seen or touched like material objects. Energy comes in many different forms, and there is a mathematical formula for computing each one. It is not surprising, then, that it took scientists most of the nineteenth century to develop an understanding of energy and to discover its important operating principle: the conservation of energy.
To understand just what energy is, it is useful to look first at the many forms in which it comes. Primary energy resources on the earth include fossil fuels, natural nuclear sources, and renewable forms of energy, such as solar, wind, hydropower, geothermal, and biomass. In principle, fossil fuels such as oil, gas, and coal are renewable but only on a geological time scale—hundreds of millions of years. The nuclear fuels, deuterium and uranium, were made during the creation of the universe (the Big Bang) and in the interior of stars on a cosmological time scale—billions of years. Therefore, fossil and nuclear energy sources are fundamentally limited and depletable (see Appendix 1). As these sources become depleted, humans will be forced to learn how to live on renewable energy—primarily on energy from the sun—as other species do.
Renewable energies include hydroelectric power generation, solar thermal energy, the direct conversion of solar energy to electrical energy (photovoltaic energy), wind energy, the capturing of the sun's energy in biomass, ocean thermal energy conversion, wave energy, geothermal energy, and tidal energy. Of these, only geothermal energy and tidal energy are of nonsolar origin; the others are indirect ways of harnessing the sun's radiation. Because solar radiation is a product of nuclear reactions in the core of the sun and geothermal energy is produced by the decay of radioactive nuclei beneath the earth's surface, only tidal and wave energy are of nonnuclear origin. Biomass is our source of food energy and, in fossil form, our main source of nonrenewable energy. Chapter 2 discusses renewable energies in more detail.
Clearly, all of these physical resources contain energy, and an interesting question to ask is, "How much energy do they contain?" The easiest way to think about measuring energy is in terms of what it can do. For example, a certain quantity of energy is required to boil a kettle of water that is initially at room temperature. The exact amount may vary depending on the efficiency of the kettle, but in a carefully controlled experiment, the energy required to boil a certain quantity of water can be measured very accurately. This energy could come directly from wood or natural gas burning in a stove, or it could come from electricity that was generated by wind turbines, nuclear reactions, or coal fires, for example. Whatever primary source was used, the quantity of energy needed to boil the water must have been extracted from that source and transformed—eventually into heat.
The idea that energy can be quantified and that measurable quantities of energy can be transformed from one form to another is central to an understanding of energy. A lump of coal or uranium contains a certain amount of useful energy. Once that energy has been taken—transformed into electricity or heat—the coal (or the uranium) does not have it anymore: Instead, the energy is stored in an electrical circuit or in the boiling water. In the same way, an hour of sunshine contains a certain amount of energy, which can be extracted with a solar panel or simply allowed to be absorbed by the earth.
The process of converting energy from one form to another is sometimes described as "work." Work and energy are examples of words that have precise, scientific meanings in addition to their more general meanings in ordinary language. If someone is described as having a lot of energy, this means the person is capable of doing a lot of work. In science, work and energy are related in a similar way: the amount of work that can be done by a person or a machine is a quantitative measure of how much energy that person or machine possesses.
Work is what you do when you move things around against resisting forces, such as friction or gravity—for example, when you push a lawn mower or carry a piano up a flight of stairs. The amount of work done depends on how hard you have to push or pull the object to make it move and on how far the object moves as it is being pushed or pulled. The first figure in Box 1.1 illustrates this idea with the example of a fairground attendant cranking a cable that pulls a car full of children to the top of a track. The attendant must do a certain amount of work, using stored biochemical energy in the body's muscles (similar to the stored energy in coal or wood), to pull the car up the slope against the force of gravity.
In a scientific sense, work requires motion, and no work is done if there is no motion. This statement implies that weightlifters must do work (and expend energy from their muscles) to raise a barbell, but they do not need to do any work (or expend any energy) to hold the barbell stationary over their head, even though this "effort" may make them feel tired. The scientific truth that work requires motion seems to contradict general experience. However, the fact that the barbell could, alternatively, be supported by a metal stand for an indefinite period of time without any energy expenditure shows that energy is not needed to hold a heavy object high in the air if the object is stationary.
But, returning to the fairground ride, what happens to the energy expended by the attendant when he pulls the car full of children to the top of the slope? Similarly, what happens to the energy expended by the weightlifter to raise the barbell? If these individuals were to continue doing this work for a long time without eating a meal (taking in more energy), they would simply run out of energy, so the energy must be going somewhere. In fact, as illustrated in the second example in Box 1.1, the attendant is transferring this energy to the car full of children in the form of potential energy (gravitational potential energy, to be exact). Similarly, the barbell acquires its potential energy from the weightlifter.
The internal structure of the car and children at the top of the track is the same as it was when they were on the ground; the only thing that has changed is their position—they have moved up in the world. Gravitational potential energy is defined as the energy possessed by an object due to its position in a gravitational field. The more work the attendant does, the higher the car rises and the more gravitational potential energy it acquires. Water backed up behind a dam is another example of stored gravitational potential energy. These energies of position have the potential to be transformed into useful work or other forms of energy.
Energy stored in fossil fuels and nuclear fuels is a form of chemical and nuclear potential energy, respectively, which depends on the relative positions of atoms in molecules (chemical energy) and protons and neutrons in atomic nuclei (nuclear energy), bound together by either electrical force fields or nuclear force fields.
Potential energy can be transformed into energy of motion, known as kinetic energy. The kinetic energy of a moving object depends on how much matter it contains and how fast it is traveling, so a high-speed tractor-trailer has a lot more kinetic energy than a slow-moving bicycle. A stationary object has no kinetic energy. In the third example in Box 1.1, the car full of children, initially stationary at the top of the track with no kinetic energy, when released starts to roll down the slope, picking up speed and, therefore, kinetic energy. By the time the car reaches the bottom of the slope, it is moving quite rapidly and has acquired a lot of kinetic energy.
The concept of kinetic energy is central to understanding why energy is so important to modern humans: we need energy to move ourselves and other things around. Most of the icons of the twentieth century—cars, trucks, and planes; agricultural equipment; and industrial machines—consume energy (much of it originating in fossil fuels) and convert it into kinetic energy to make something move.
So far, we have discussed physical stores and sources of energy, such as fossil fuels, nuclear sources, the wind, and the sun. We have also shown how the energy in these physical sources can be converted into more conceptual forms, such as potential energy (energy of position) and kinetic energy (energy of motion). The final form of energy we will consider is heat.
Historically, heat and motion were viewed as separate areas of physics. However, in the 1840s, the English physicist James Prescott Joule demonstrated the connection between heat and mechanical (kinetic) energy by measuring the rise in temperature of a liquid when it was stirred by a paddle wheel. Because of Joule's discovery, heat is now recognized as another form of energy that can be generated from other forms of energy (including chemical, potential, and kinetic) and converted into other forms. An example of the partial conversion of heat energy into mechanical (kinetic) energy is the steam engine or the internal combustion engine. The efficiency of a heat engine is defined as the fraction of the input heat energy that is converted into mechanical energy. Since the heat is usually produced by burning coal, gasoline, or some other kind of fuel that must be paid for, heat engines are designed to have the greatest possible efficiency. Although their efficiency has greatly increased since the early steam engine, it is impossible (according to the second law of thermodynamics) to make a perfect heat engine—that is, an engine with 100 percent efficiency. Some of the fuel's energy must be discharged as waste heat. The efficiencies of modern steam engines are typically 30 to 40 percent. The efficiency of an ordinary automobile engine is 20 to 30 percent, and that of a large diesel oil engine is about 40 percent.
Interestingly, when heat energy is examined at the molecular or atomic scale, it turns out to be a form of kinetic energy—energy of random motion of molecules and atoms. The scientific study of heat and the transformation of mechanical energy into the random motion of molecules and atoms is known as thermodynamics, and the random movements and vibrations are often referred to as internal energy or thermal energy. Since thermal energy is nothing more than the kinetic energy of atoms and molecules, thermodynamics connects the macroscopic (human-scale) and microscopic (atomic-scale) domains of nature. Like heat, sound energy also involves molecular vibrations, which spread out and die away rapidly as the vibrational energy is distributed and diluted among increasing numbers of molecules.
A crucially important characteristic of heat (which we will consider in more detail in a later section) is its tendency to flow spontaneously from a hot region to a cooler region.
Joule's work on the equivalence of heat and mechanical energy (for which his name was given to the scientific unit of energy) laid the foundation for understanding an immensely powerful law of nature: the conservation of energy, known to scientists as the first law of thermodynamics.
(Continues...)
Excerpted from Energy by Lloyd Orr, Robert Bent, Randall Baker. Copyright © 2002 Island Press. Excerpted by permission of ISLAND PRESS.
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Table of Contents
PrefaceForeword
Acknowledgements
Introduction: The Energy-Environment Problem
Chapter 1. Rules of the Game Robert Bent, Andrew Bacher, and Ian Thomas
Chapter 2. Future World Energy Needs and Resources John Sheffield
Chapter 3. Environmental Impacts of Energy Use Russell Lee
Chapter 4. Culture and Energy Consumption Richard R. Wilk
Chapter 5. Energy Policy: The Problem of Public Perception Randall Baker
Chapter 6. Energy and Sustainable Economic Growth Lloyd Orr
Chapter 7. Protecting Future People: The Motivation Problem \ Norman S. Care
Conclusion
Appendices
About the Contributors
Index