Energy Use: Our Growing Dependence on Nonrenewable Fuels What Is Energy?
275
Energy comes in many forms. In most industrial nations, coal,oil, and natural gas are the predominant fuels. These non-renewable forms of energy are the lifeblood of modern indus- trial societies, but they are also a potential Achilles’ heel. If you cut the supply off for even a brief moment, industry would come to a standstill. Agriculture and mining would halt. Millions would be out of work. Automobiles would vanish from city streets. Al- most everything in our homes would cease to operate. In addition, as the Gulf oil spill in 2010 showed, our dependence on these fuels can be extremely costly!
Many of the less developed nations have pinned their hopes for economic progress on their ability to tap into oil, coal, natural gas, and to a lesser extent nuclear power, which have fueled the indus-
Nonrenewable Energy Sources
Energy Use: Our Growing Dependence on Nonrenewable Fuels What Is Energy? Fossil Fuels: Analyzing Our Options Fossil Fuels: Meeting Future Demand Nuclear Energy Guidelines for Creating a Sustainable Energy System Establishing Priorities
Spotlight on Sustainable Development 14-1: Controversy Over Oil Exploration in the Arctic National Wildlife Refuge Spotlight on Sustainable Development 14-2: Coca-Cola Goes Green Point/Counterpoint: Should We Drill for Oil in the Arctic National Wildlife Refuge? Point/Counterpoint: Should Nuclear Power Be Revived?
14.7
14.6 14.5
14.4
14.3 14.2
14.1
CHAPTER OUTLINE
CHAPTER 14
That human beings are fallible has been known since the beginning of time, but modern technology adds new urgency to the recognition.
—Garrett Hardin
276 PART IV. Resource Issues: Solutions for a Sustainable Society
FIGURE 14-1 Chang- ing options. Energy consumption in the United States by fuel type from 1850 to the present. As this graph shows, U.S. energy de- pendence has shifted over the years from wood to oil, coal, and natural gas. (Quad = quadrillion BTUs.) Source: US Statistical Abstract.
CRITICAL THINKING
Exercise Global climate change has led many propo- nents of nuclear energy in the United States to lobby the public and Congress for renewed support of nuclear energy to lessen America’s dependence on foreign oil and coal. Adver- tisements in prominent magazines still tout the benefits of nuclear power. In such ads, proponents of nuclear power note that this technology has the added benefit of not contributing to global warming, a problem worsened by the combustion of fossil fuels— especially coal, oil, and oil byproducts such as gasoline, jet fuel, and diesel.
Is this thinking valid? Why or why not?
oil, natural gas, and nuclear energy. It looks at their impacts and their abundance. It ends with some guidelines on creating a sustainable energy future.
Energy Use: Our Growing Dependence on Nonrenewable Fuels
U.S. and Canadian Energy Consumption One hundred years ago, Americans had few choices for en- ergy (FIGURE 14-1). Wood, a renewable resource, was the main form of energy. Today, the nation’s options are many: coal, oil, natural gas, hydropower, geothermal energy, solar power, nuclear power, and wind.
American energy options began to expand in the late 1800s as wood, which once fueled the nation’s factories, became depleted. Coal began to be used in factories, but coal was a dirty, bulky fuel that was expensive to mine and transport. When oil and natural gas were made available in the early 1900s, coal use began to fall. The new, cleaner-burning fuels were easier and cheaper to transport.
Today, despite numerous energy options, the United States depends primarily on three fossil fuels: oil, natural gas, and coal. In 2008, oil accounted for 37% of total energy con- sumption (FIGURE 14-2a). Natural gas provided 24%, and coal provided nearly 23% of the energy. All told, fossil fuels account for nearly 85% of our energy use. Nuclear power, another nonrenewable fuel, provided 8.5%. Renewable sources—solar, geothermal, and hydropower—supplied a little over 7%.
Canada is also heavily dependent on fossil fuels. In 2008, coal, oil, natural gas, and other fossil fuels accounted for 66% of the nation’s total energy consumption. Canada relies heav- ily on nuclear energy, which meets 7% of its total demand. Wood makes up the remaining supplies along with renewable
14.1
Nuclear energy
Hydropower, geothermal, and others
Natural gas
Oil
Coal
Wood
E ne
rg y
co ns
um pt
io n
(q ua
ds )
0 1860 2003 2006 2009
100
90
80
70
60
50
40
30
20
10
1880 1900 1920 Year
1940 1960 1980
trial transformation of the wealthy nations. China, for example, is hoping to get much of its future en- ergy from its abundant supplies of coal and from oil it imports from other countries. According to several sources, China is building hundreds of coal- fired power plants to supply electricity to its vast and continually growing population, which is experiencing rapid economic growth.
Is the industrial world’s dependence on coal, oil, natural gas, and nuclear energy sustainable? Can less developed nations achieve success by follow- ing in our footsteps?
This chapter examines the sustainability of the predominant nonrenewable energy fuels—coal,
CHAPTER 14: Nonrenewable Energy Sources 277
FIGURE 14-2 The U.S. energy profile. (a) This pie chart shows the major energy sources in the United States in 2009. Oil, natural gas, and coal are the three most commonly used fuels. (b) Ma- jor energy consumers in the United States. Indus- try and transportation lead the pack.
energy, primarily hydroelectricity, energy which supplies about 25% of Canada’s annual energy demand. Renewable energy from solar and wind sources provide negligible amounts of power.
FIGURE 14-2b breaks down energy consumption by user in the United States in 2009. As it shows, industry and the com- mercial sector consume about 50% of the nation’s energy. Transportation consumes about 28%, and residential use ac- counts for about 22.4%.
KEY CONCEPTS
Global Energy Consumption Virtually all industrial nations get the energy they need from nonrenewable energy sources. On average, they receive about 85% of their energy from fossil fuels, 5% from nuclear power, a type of nonrenewable energy, and 10% from renewables such as solar and wind energy, although the renewable en- ergy contribution is growing rapidly in many countries such as the United Kingdom, Germany, Japan, Spain, and Den- mark. (FIGURE 14-3a). In the less developed countries, renew- able energy sources such as biomass (wood and cow dung, for example) play a much more important role in supplying de- mand, satisfying about 40% of their energy requirements (FIG- URE 14-3b). Nonrenewable fossil fuels supply about 60% of the total energy. Of nonrenewable energy fuels used in these coun- tries, oil supplies the largest share. Coal and natural gas sup- ply the rest. Nuclear power contributes only a tiny fraction of their energy demand, in large part, because of the high cost of this option.
Worldwide, the biggest users of energy are Americans, who make up about 4.6% of the world’s population but con- sume about 25% of its primary energy. On a per capita ba- sis, Americans consume more than twice as much energy as the people of Japan and Western Europe and about 16 times more per capita than the people of less developed nations. Canada is also a major consumer of energy, using more per capita than any other nation except for Luxembourg. With only 0.6% of the world’s population, Canada uses
Energy use in the United States has shifted considerably over the years. Today, the United States depends on a variety of fuel sources. Fossil fuels provide the bulk of the energy. Industry and business consume the majority of the fuel. Transportation is another major energy consumer.
2.5% of the world’s energy. The reasons for this are many. It is a large country, situated in a cold climate. It has an energy-intensive industrial economy with logging, mining, agriculture, and energy production as the
chief sources of income. The extraction and processing of energy resources alone contributes 7% to the nation’s Gross Domestic Product. Historically, energy prices have been low and Canadians tend to use energy inefficiently.
KEY CONCEPTS Like the United States, most more developed countries rely pri- marily on fossil fuels. Least developed countries depend on fos- sil fuels as well, but they also receive a substantial amount of energy from various renewable fuels, especially biomass. Amer- icans make up a small portion of the world’s population but ac- count for a very large percentage of global energy consumption.
Coal Transportation
Industry
(a) Ene r gy sou r ces (b) Ene r gy consume r s
Commercial
Residential
Oil
Nuclear 8.5%
Solar, geothermal, and hydroelectric 7.3%
Natural gas
37.4%
22.5%
24%
28.5%
29.8% 19.2%
22.4%
MDCs
LDCs
Nuclear Power
Natural Gas 23%
Coal 25%
Oil 37%
7%
5%
Biomass 3%
Nuclear Power 1%
Natural Gas 7%
Coal 25%
Oil 26%
Biomass 35%
Hydropower, geothermal, solar
Hydropower, geothermal,
solar 6%
Renewable Resources
Nonrenewable Resources
41%
59%
10%
90%
FIGURE 14-3 Global energy use. (a) More developed countries. (b) Less developed countries.
(a)
(b)
278 PART IV. Resource Issues: Solutions for a Sustainable Society
What Is Energy? Energy is all around us, but it is sometimes difficult to de- fine. But what exactly is it?
Energy Comes in Many Forms Let’s begin by making a simple observation as a way to help define this term: Energy comes in many forms. For example, humans in many countries rely today on fossil fuels such as coal, oil, and natural gas. Some use a lot of nuclear energy to generate electricity. In other countries, wood and other forms of biomass are primary forms of energy. (Biomass in- cludes a wide assortment of solid fuels, such as wood, and liquid fuels, such as ethanol derived from corn, and biodiesel, a diesel fuel made from vegetable oils.) And don’t forget sun- light, wind, hydropower, and the geothermal energy—energy produced in the Earth’s interior. Even a cube of sugar con- tains energy! Touch a match to it, and it will burn, giving off heat and light energy, two additional forms of energy.
Energy Can Be Renewable or Nonrenewable Energy in its various forms can be broadly classified as either renewable or nonrenewable. Renewable energy, as noted earlier, is any form of energy that’s regenerated by natural forces. Wind, for instance, is a renewable form of energy. It is available to us year after year, thanks in large part to the unequal heating of the Earth’s surface. When one area is warmed by the sun, for instance, hot air is produced. Hot air rises, and as it does, cooler air moves in from neighboring areas. As the cool air moves in, it creates winds of varying intensity. Renewable en- ergy is everywhere and is replenished year after year, provid- ing humankind with a potentially enormous supply . . . if only we’re smart enough to tap into it!
Nonrenewable energy, on the other hand, is finite. It can- not be regenerated in a timely fashion by natural processes. Coal, oil, natural gas, tar sands, oil shale, and nuclear energy are all nonrenewable forms of energy. Ironically, although most of these sources of energy were produced by natural bi- ological and geological processes early in the Earth’s history, and, although these processes continue today in some parts of the world, these fuels are not being produced at a rate even remotely close to our consumption. Coal, for instance, may be forming in some swamplands around the world. But its re- generation is taking place at such a painfully slow rate that it is meaningless. Put another way, contemporary produc- tion can never replenish the massive supplies that were pro- duced over long periods of time many millions of years ago. Because of this, coal, oil, natural gas, and others are essentially finite. When they’re gone, they’re gone.
So, now you know two basic facts about energy: energy comes in many forms, and all forms of energy broadly fit into two general categories: renewable and nonrenewable.
Energy Can Be Converted from One Form to Another Yet there’s more to energy than this. For example, even the ca- sual observer can tell you that energy can be converted from one form to another. Natural gas, for example, when burned
14.2 is converted to heat and light. Coal, oil, wood, biodiesel, and other fuels are also converted to other forms of energy dur- ing combustion. Heat, light, and electricity are the most com- mon byproducts of these conversions, but the possibilities don’t end here. Visible light contained in the sun’s energy can be converted to heat. It can also be converted to electrical energy. Even wind can be converted to electricity or to me- chanical energy to drive a pump to draw water from the ground.
Energy Conversions Allow Us to Put Energy to Good Use Not only can energy be converted to other forms, it has to derive benefit for us. Coal, by itself, is of little value to us. It’s a sedimentary rock and fun to behold, but it is the heat and electricity produced when coal is burned in power plants that are of value to us. Sunlight is pretty, too, and it feeds the plants we eat; but in our homes and factories, however, it is the heat that the sun produces and the electricity we can generate from it that is of primary value to us.
In summary, then, it is not raw forms of energy that we need. Not at all. It is the byproducts of energy that are un- leashed when we “process” them in various energy-liberating technologies that meet the complex needs of society.
Energy Can Neither Be Created nor Destroyed Another thing you need to know to deepen your under- standing of energy is that energy cannot be created nor can it be destroyed. Physicists call this the First Law of Thermo- dynamics or, simply, the First Law.
The First Law says that all energy comes from pre- existing forms. Even though you may think you are “creat- ing” energy when you burn a piece of firewood in a woodstove, all you are doing is unleashing energy contained in the wood—specifically, the energy locked in the chemi- cal bonds in the molecules that make up wood. It, in turn, came from sunlight. The sun’s energy came from the fusion of hydrogen atoms in the sun’s interior.
Energy Is Degraded When It Is Converted from One Form to Another More important to us, however, is the Second Law of Thermo- dynamics. The Second Law, says, quite simply, that anytime one converts a form of energy to another form—for example, when you convert natural gas to heat—it is degraded. Trans- lated, that means energy conversions transform high-quality energy resource to low-quality energy. Natural gas, for in- stance, contains a huge amount of energy in a small volume; it’s locked up in the simple chemical bonds that attach the car- bon atom to the four hydrogen atoms of the methane mole- cules. When these bonds are broken, the stored chemical energy is released. Light and heat are the products. Both light and heat are less concentrated forms of energy, or lower qual- ity forms of energy. Hence, we say that natural gas, a concen- trated form of energy, is “degraded.” In electric power plants,
CHAPTER 14: Nonrenewable Energy Sources 279
only about 50% of the energy contained in natural gas is con- verted to electrical energy. The rest is “lost” as heat and is dissipated into the environment.
No Energy Conversion Is 100% Efficient, Not Even Close to It! This leads us to another important fact about energy: No energy conversion is 100% efficient. When coal is burned in an electrical power plant, only about one-third of the en- ergy contained in the coal is converted to useful energy, in this case, electricity. The rest is lost as heat and light. The same goes for renewable energy technologies. One hundred units of solar energy beaming down on a solar electric module won’t produce the equivalent of 100 units of electricity. You’ll only get around 12 to 15% conversion on the most popular modules on the market today.
Energy is lost in all conversions. One hundred units of electrical energy won’t produce 100 units of light energy in a standard incandescent lightbulb. In fact, most conven- tional lightbulbs in our homes (incandescent lights) con- vert only about 5% of the electrical energy that runs through them into light. The rest comes out as heat!
Each conversion in a chain of energy conversions loses useful energy, as shown in FIGURE 14-4. Don’t forget that. To get the most out of our primary energy sources, we must re- duce the number of conversions along the path.
But let’s get something straight. Some of you may be wondering whether all of this discussion of “energy losses” is violation of the First Law, which states that energy cannot be created nor destroyed.
The truth be known, the “energy losses” I’ve been talk- ing about during energy conversion are not really losses in the true sense of the word. Energy is not really destroyed; it is released in various forms, some useful and others, such as heat, not so useful. Chemical energy in gasoline that runs a car, for instance, is converted to mechanical energy of mov- ing parts that propel us forward along the highways. Some is also lost as heat that radiates off the engine. This waste heat is of little value except to use on cold winter days when cap- tured, at least in part, to warm the car’s interior.
Eventually, however, all heat produced by a motorized vehicle escapes into outer space. It is not destroyed, per se;
it escapes into space and is no longer available to us. Hence, the conversion results in a net loss of useful energy.
By now you know that there are many forms of energy. You know that energy can be renewable or nonrenewable. You understand that raw energy is not as important to us in our homes as is the useful byproducts such as electricity, light, or heat. You now also know that energy can neither be cre- ated, nor destroyed. It can only be converted from one form to another, and you’re privy to the fact that no energy con- version is 100% efficient, not even close.
You also understand that during conversions useful en- ergy decreases. Put another way, all conversions lose energy as heat that is dissipated into outer space. That fact, in turn, is important for nonrenewable fuels; once they’ve burned or reacted in the case of nuclear fuels their energy is gone for- ever. The heat radiates endlessly into outer space, heating the universe as it were.
Renewable energy resources, on the other hand, can be regenerated year after year after year. If we’re going to per- sist as a society in the long term, it is renewable energy re- sources we’ll need to rely on. Unlike fossil fuel energy and nuclear energy, renewable resources can return again and again, making our lives bright and cheery and comfortable so long as the sun continues to illuminate the daytime sky. With these important points in mind, let’s define this thing we call energy.
Energy Is the Ability to Do Work To a physicist, energy is defined as “the ability to do work.” More accurately, says engineer John Howe, “Energy is that elusive something that allows us to do work.” We and our machines, that is.
Any time you lift an object, for example, or slide an ob- ject across the floor, you are performing work. The same holds for our machines. Anytime a machine lifts something or moves it from one place to another, it performs work.
Energy, quite simply, is valuable because it allows us to perform work. It powers our bodies. It powers our homes. It powers our society. We cannot exist without energy.
According to physicists, work is also performed when the temperature of a substance, for example, water, is raised. Therefore, your stove or microwave is working when it boils water for hot tea or soup.
Radiant energy
Heat Heat Heat Heat Heat Heat
Sunlight
Chemical energy
Photosynthesis
Chemical energy
Coal
Thermal energy
Coal-burning power plant
Mechanical energy
Steam-driven turbine
Electrical energy
Transmission tower
Radiant energy
Computer monitor
FIGURE 14-4 Different forms of energy. Energy can be changed from one form to another; however, with each change a certain amount of energy is lost as heat. (Adapted from D. D. Chiras, et al. Management for a Sustainable Future, Ninth edition. Pearson Education [2005]: Upper Saddle River, NJ.)
280 PART IV. Resource Issues: Solutions for a Sustainable Society
Fossil Fuels: Analyzing Our Options
Energy is the lifeblood of modern society, but it does not come cheaply. In addition to its economic cost, huge envi- ronmental costs are posed by many forms of energy. As you shall soon see, these impacts lead many to conclude that the current energy system is unsustainable. When analyzing the sustainability of the world’s energy system, one must take into account available supplies as well as the impacts to the en- vironment, climate, and human health. This section exam- ines those impacts. Before we can understand them, though, we must first understand the many steps required to deliver energy to our homes, factories, and gas stations.
FIGURE 14-5 presents a diagram of some of the major steps involved in energy production and consumption. This chain of events constitutes an energy system and is composed of six major phases: exploration, extraction, processing, distribution, storage, and end use. Take a moment to familiarize yourself
14.3 with these steps. As a rule, the most notable environmental impacts occur at the extraction and end-use phases.
Understanding energy systems and the impacts along the way makes it clear that a simple flick of a light switch or a press on the gas pedal of an automobile creates a trail of en- vironmental damage. It shows our personal connection to the long list of environmental problems facing the world.
KEY CONCEPTS
Crude Oil Crude oil or petroleum is a thick liquid containing many combustible hydrocarbons (organic compounds made of hy- drogen and carbon). Found in deep deposits in the seafloor
Energy does not come cheaply. In addition to the economic costs, society pays a huge environmental price for its use of nonrenew- able energy in damage to the health of its people and to the en- vironment. These impacts arise at every phase of energy production. The most significant impacts arise from extraction and end use.
Longwall
Room-pillar
Auger
Truck
Conveyor
Mine rail
Barge
Tanker
Supertanker
Pipeline Refineries
National Tank truck
Tank car
Barge
Tanker
Tanker (product imports)
Pipeline
Pipeline Gas holders
LNG tanker
LNG truck
LNG truck Regasification
Storage tank
Tank truck
Tank car
Coke clean
Steam clean
Break-size
Mixed train
Unit train
Barge Generation
Transmission Truck
Aboveground
Underground
Silo
Metallurgical
Electrical
Generation
Transmission
Electrical
Generation
Transmission Electrical
Space conditioning
Other
Space conditioning
Other
Transportation
Other
Beehive
Slot oven
Conveyor
Coal
R es
ou rc
e
Tr an
sp or
ta tio
n
Pr oc
es si
ng
D is