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?
That human beings are fallible has been known since the beginning of time, but modern technology adds new urgency to the recognition.
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.
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
Hydropower, geothermal, and others
0 1860 2003 2006 2009
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%.
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.
(a) Ene r gy sou r ces (b) Ene r gy consume r s
Solar, geothermal, and hydroelectric 7.3%
Natural Gas 23%
Nuclear Power 1%
Natural Gas 7%
Hydropower, geothermal, solar
FIGURE 14-3 Global energy use. (a) More developed countries. (b) Less developed countries.
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.
Heat Heat Heat Heat Heat Heat
Coal-burning power plant
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 : 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.
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.
National Tank truck
Tanker (product imports)
Pipeline Gas holders
LNG truck Regasification
LNG separation Underground
Contour strip mining
Area strip mining
FIGURE 14-5 Energy systems. Most of us are unaware of the many steps involved in providing us with energy.
Once located, crude oil is extracted via wells drilled into deposits. Oil flows into the well and is pumped to the sur- face. Oil companies once thought that the yield from oil wells would be greatly increased by injecting water, steam, and carbon dioxide into the ground, which forces additional crude oil to the surface. Today, geologists realize that these techniques do not increase yield.
Once the crude oil is extracted, it is transported by pipeline, truck, or ship to refineries for processing. Transporta- tion of oil by ships and pipelines is a source of considerable environmental damage. Ships sometimes run aground and spill their contents into lakes and oceans, with devastating environmental consequences (Chapter 21). Oil drilling can be a major source of water pollution. Small leaks at offshore wells, for example, can result in oil contamination. Major leaks, such as the well blowout at the BP oil platform in the Gulf of Mexico, can also occur (FIGURE 14–7). The “spill” in the Gulf of Mexico occurred 5,000 feet below the surface and affected sea water and organisms from seafloor to the ocean’s surface. The environmental and economic effects of the spill were enormous, and could persist for decades. (For more on the BP oil spill, see Chapter 21). Pipelines may leak or break, causing additional problems. For a discussion of the potential impacts of oil development in the Arctic, see Spotlight on Sustainable Development 14-1.
In a refinery, the oil is heated and distilled. This separates out many of the different hydrocarbon molecules in crude oil—including those that make up gasoline, diesel fuel, heat- ing oil, and asphalt. Many small organic compounds are also extracted during this process and are used to make medicines, plastics, paints, and pesticides (FIGURE 14–8). Refineries use considerable amounts of energy and are major sources of air and water pollution.
The combustion of crude oil derivatives such as gasoline and diesel fuel produces enormous quantities of carbon diox- ide (a greenhouse gas) and other pollutants such as sulfur diox- ide and nitrogen dioxide, both of which are converted into acids in the atmosphere (Chapter 20). In fact, many of the most significant local and global environmental problems stem from the combustion of oil and its byproducts.
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FIGURE 14-6 Horizontal Oil Well Drilling. Although it is challeng- ing, oil can be tapped from drill rigs located several miles from the oil deposit, as shown here. This may help to reduce the impact that oil drilling and oil extraction can have on sensitive ecosystems.
FIGURE 14-7 Oil spill in the Gulf. An explosion in an oil well in the Gulf of Mexico in 2010 resulted in the release of millions of gallons of oil for several months. The oil spread throughout much of the Gulf, affecting beaches, tourism, and countless wetlands. This is just one of many of the impacts of our depend- ence on oil.
and on land, crude oil often occurs with natural gas. Geolo- gists locate oil deposits through a careful study of geology— that is, the type of rocks found in various regions—and by other fairly low-impact means. However, to explore for oil in remote areas, roads must often be built so that exploration crews can enter. In Alaska and Canada, plans are in the offing to move into pristine northern areas as far north as the Arctic where oil companies, supported by government subsidies, hope to explore and eventually drill for oil. One promising tech- nology that could reduce the impact of oil development in such areas is horizontal oil well drilling (FIGURE 14–6). A typical oil well is drilled from the top. A horizontal oil well is one that approaches the oil reservoir from the side, often some distance away. Using this technique, oil companies believe they can tap into oil reserves without entering extremely sen- sitive ecosystems. Even so, the impacts could be devastating. Numerous roads, oil processing facilities, power plants, land- ing strips, parking lots, worker housing, and other buildings must be erected in environmentally sensitive areas.
282 PART IV. Resource Issues: Solutions for a Sustainable Society
Natural Gas Natural gas is a mixture of low molecular weight hydrocar- bons, mostly methane. It also contains small amounts of propane and butane that can be extracted, compressed, and liquefied. Butane is used in grill lighters; propane can be used to heat homes, cook, and heat water for domestic uses. Burned in homes, factories, and electric utilities, natural gas is often described as an ideal fuel because it contains few contaminants and burns cleanly. Substituting natural gas for coal in electric generating power plants, for instance, re- duces carbon dioxide emissions by 50 to 70%. But precautions must be taken so methane in natural gas doesn’t leak. Methane is 30 times more powerful as a greenhouse gas, so losses of only 3 to 4% of the methane could offset any benefit. Natural gas plants also frequently burn off excess gas, a process called
Oil is extracted from deep wells on the seafloor and on land; it is often found in association with natural gas. After it is extracted, crude oil is heated and distilled, a process that separates the components of oil, which produces useful fuel and nonfuel byproducts. The major impacts of the oil energy system come from oil spills and from combustion of oil and its byproducts.
Other 0.3 gallons Kerosene 0.2 gallons Lubricants 0.5 gallons Feedstocks 1.2 gallons Asphalt/road oil 1.3 gallons Petroleum coke 1.8 gallons Still gas 1.9 gallons Liquefied gases 1.9 gallons Residual fuel oil 2.3 gallons
Jet fuel 4.1 gallons
Distillate fuel oil 9.2 gallons
Gasoline 19.5 gallons
FIGURE 14-8 Products from a 44-gallon barrel of oil. Total is more than 44 because of “processing gain.” (Data from the Ameri- can Petroleum Institute.)
SPOTLIGHT ON SUSTAINABLE DEVELOPMENT
14-1 Controversy Over Oil Exploration in the Arctic National Wildlife Refuge
In the far northeastern corner of Alaska lies the Arctic Na- tional Wildlife Refuge, or ANWR. Set aside to protect wildlife, this refuge encompasses 7.7 million hectares (19 million acres). It has been described as the last great American wilderness. With strong support of the Bush administration, a portion of ANWR was opened to development. If oil is found, many suspect that widespread drilling will occur in the coastal plain, a 0.6-million-hectare (1.5-million-acre) region—an area almost as large as Yellowstone Park.
The delicate Arctic tundra of the coastal plain, a region 210 kilometers (115 miles) long and 50 kilometers (30 miles) wide, is the only section of land along the entire 1800- kilometer (1,100-mile) north coast of Alaska that is closed to oil exploration and drilling. The coastal plain is the annual calving ground of several large caribou herds. It is also home to polar bears, grizzlies, wolves, moose, wolverines, and nu- merous small mammals. Many thousands of birds spend the summer there, raising their young and feeding on insects.
In 1991, after public protest over the tragic 1989 oil spill in Prince William Sound subsided, President George Bush and the oil companies introduced legislation that would al- low drilling in the ANWR. Because of a massive outpouring of public protest, the bill was defeated, but the oil compa- nies continued to push legislation that would permit them to explore for oil within this magnificent wildlife refuge.
In 2005, a couple of major oil companies reportedly withdrew support, after having conducted secret exploration in the region. Despite their having concluded that oil devel-
opment in the area would be uneconomic, the Bush Admin- istration and Republican leaders unsuccessfully pushed for leg- islation that would open up a small but significant portion of ANWR to oil development. Although they hope to minimize damage by special drilling techniques, many conservation- ists fear that the pristine region will eventually be turned into a maze of roads, oil platforms, waste ponds, buildings, and gravel pits (FIGURE 1). Full-scale development would lead to construction of four airfields and 50 to 60 oil platforms. A power plant and several oil-processing plants would be built
FIGURE 1 An oil drilling pad in Prudhoe Bay, Alaska. The delicate Arctic tundra will be damaged to supply more oil to sat- isfy America’s needs.
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on the tundra, and hundreds of kilometers of roads and pipelines would crisscross this delicate land. The rising tem- peratures discussed in Chapter 10 are threatening the Arctic tundra, which could dramatically alter plans to drill for oil in the Arctic. Currently, oil operations are permitted only when the Arctic tundra is frozen at least 30 centimeters (12 inches) and covered with at least 15 centimeters (6 inches) of snow. Because of global warming, the “window of opportunity” has shrunk from 200 days per year to only 100.
While proponents think that oil development and wildlife can coexist in harmony, critics predict a 20 to 40% decline in one of the major caribou herds. They expect over half of the musk oxen to perish. Populations of grizzlies, polar bears, wolverines, and other animals are also likely to decrease substantially. Air pollution, water pollution, and hazardous wastes are expected to have major impacts on wildlife and the long-term ecological health of the region. One exploratory well alone requires 35,000 cubic meters of gravel, which would be excavated from streambeds to make pads and roads. Oil spills on the tundra and careless waste disposal, common in nearby Prudhoe Bay, would change this delicate landscape, whose short growing seasons and harsh winters greatly impair the natural healing that normally takes place in the wake of human interference.
Proponents argue that we need the oil to cut reliance on foreign sources and that we need to drill for oil in ANWR now because of the 10- to 15-year lead time required to fully de- velop the area. Geologic evidence, some say, indicates a high
potential for oil discovery, and oil is needed to help bolster Alaska’s economy. They say that environmental regulations will ensure minimal impacts on wildlife and the environment.
Those in favor of preserving the refuge intact argue that the environmental costs are too high. Experience in nearby Prudhoe Bay shows that oil companies often ignore environ- mental regulations. Frequent violations have been cited. The Department of Interior has recorded over 17,000 oil spills since 1973 in the Arctic. In 2007, a record spill of 1,033,290 liters (267,000 gallons) occurred from a pipeline in a caribou cross- ing area in Alaska’s North Slope. Where the oil saturates the soil, vegetation fails to recover. Opponents of exploration also argue that because the entire north coast of Alaska is already open to oil exploration, the ANWR should not be— now or ever. If there’s oil there, let it lie. Let us find alterna- tives and let the wildlife live in peace. Furthermore, they point out that slight improvements in automobile gas mileage could easily “provide” as much oil as the ANWR could gen- erate over its lifetime—and at a much lower cost. Moreover, critics say that the proponents have exaggerated the poten- tial for finding oil that is economically feasible to recover. Based on the oil industry’s own reports, they say, there’s only a one in five chance of finding economically recoverable oil.
Few of us will ever visit the ANWR, but many of us take comfort in knowing there are places where wildlife are free of the intrusion of modern industrial society. Those places, say opponents, may not last. For more on the debate see the Point/Counterpoint on the following page.
flaring. This process releases hydrogen sulfide gas and a va- riety of pollutants, including carbon dioxide, carbon monox- ide, and volatile organic compounds that are harmful to people and the environment, as you will see in Chapters 18 and 19. The Alberta Research Council identified 200 chem- ical compounds in flare gas. In Alberta, 1.4% of the natural gas drawn from wells is flared.
Like oil, it is easy to transport natural gas within countries via pipelines. It is much more difficult to transport overseas, however. To do so, it must be compressed or compressed and liquified. It is then transported by ship. Natural gas is also fairly economical and requires relatively little energy to extract.
Natural gas is often associated with oil deposits and coal beds though it can be found by itself as well. In the eastern U.S., natural gas is found in deep deposits of shale. In recent years, scientists and energy companies have grown excited about a potentially large deposit in the eastern U.S. known as Marcellus Shale.
Natural gas comes from wells as deep as 10 kilometers (6 miles). On land, drilling rigs generally have minimal im- pact unless they are located in wilderness areas, where op- erations destroy valuable land and roads and noise from heavy machinery and construction camps can disturb wildlife. However, natural gas extraction can cause subsidence in the
vicinity of the well. One no- table example is in the Los Angeles-Long Beach harbor area, where extensive oil and gas extraction began in 1928 and has caused the ground to drop 9 meters (30 feet) in some areas.
Natural gas is generally safe to transport in the gaseous form in pipelines, but as noted earlier, to trans- port it across oceans, it must be compressed. In the liq- uid form, natural gas is unstable and highly flammable. A ship containing liquefied natural gas could burn intensely.
KEY CONCEPTS Natural gas is a combustible gas extracted from deep onshore and offshore wells. Natural gas is used to heat homes, cook food, and heat water. It is also used by factories and some power plants. It is easy to transport within countries or from one coun- try to its terrestrial neighbors. Natural gas is a clean fuel com- pared to oil, oil byproducts, and coal.
Wearing more clothing, even insulating underwear and sweaters, indoors in the winter greatly increases comfort. Dress in several layers so you can find just the right combination to create comfort. By wearing warmer clothing, you can turn the thermostat down, saving energy and the environment.
Debate over oil exploration in the 10-02 area of the Arctic Na- tional Wildlife Refuge (ANWR) has been going on since the late 1980s and the topic has turned into more of a political foot- ball and fundraising tool rather than a rational discussion on energy consumption and care for the environment. The oil industry has largely abandoned the debate, leaving Congress to argue back and forth, year after year, getting little done.
Politically the problem lies in the need for 60 votes to overcome a filibuster in the Senate. ANWR bills are contin- ually threatened with filibusters. Meanwhile we continue producing less oil, while consuming more.
Alaskans support drilling in ANWR overwhelmingly. Our economic future and livelihoods depend on it. Eighty-seven percent of our economy is based on North Slope oil, and with the Trans-Alaska Pipeline less than half full and decreasing fast, Alaskans are getting worried. Without oil taxes and roy- alties, the economy of the state would nose-dive. Expect ma- jor job losses and a decline in social infrastructure. The effect locally on the Inupiut native populations of the Arctic would be even more extreme, as their economy is near 100% reliant on tax revenue from oil. The local clinic, the school, the vil- lage fire truck, the sewer and water system would not exist— and did not exist—without oil tax revenues.
Many Native Alaskans see opposition to oil develop- ment in ANWR as a quiet attempt to force them out of exis- tence. Opponents are denying the right of a people to use their private lands as they see fit (over 100,000 acres [40,500 hectares] of the 10-02 is private property).
ANWR is an issue of self-determination, human rights, and imperialism. The Alaskan Natives have walked and used the land for 40,000 years and are the true environmental- ists. They should be allowed to live productive lives, access what is rightfully theirs and build their futures like every other American. To drive this point home, the Alaska Federation of Natives, which represents all native peoples in the state, has supported development in the 10-02 with yearly reso- lutions since the debate started.
The fact is America needs oil and will for 100 years to come. Oil provides thousands of products we use everyday as well as raw energy that’s turned into fuels. Oil lubricates wind turbine gears, oil produces polymers and resins used to produce components of hybrid cars, oil produces synthetic rubber used for tires, and bitumen for the roads they roll on. Natural gas also comes from oil wells and allows us to pro- duce fertilizers to grow biofuel crops. From paint, to medi- cine, to fire retardants, to detergents and ink, oil is vital to our current lifestyle.
If you have to have oil, which we do, you have a choice to get it from home where you can control its production and benefit from the jobs and infrastructure or buy your oil from abroad where you have no control and are, in an economic sense, just burning dollar bills (we currently spend $37,750,000 per hour importing oil).
Pollution knows no boundaries and importing oil turns a blind eye to the environmental practices of producers. An oil spill caused by careless production in Nigeria is just as bad as one in Alaska. In Alaska, however, we have the strictest rules and regulations on Earth to mitigate and prevent ca- tastrophes. A dozen federal, state, and local agencies mon- itor activity in the Alaskan Arctic 24/7 every day of the year. We do the best job humanly possible to protect our environ- ment. Remember Alaskans live in Alaska because they pre- fer the wild nature and open spaces. Alaskans find it ironic that others believe we would do anything to destroy the very reason we moved there in the first place.
Much of the debate over the 10-02 area of ANWR cen- ters around the porcupine caribou herd. Outside “environmen- talists” claim there will be caribou armageddon and all the wildlife will be destroyed and land irreparably damaged. Nothing could be further from the truth. These same concerns were raised by groups back in the early ‘70s during the con- troversy over the development of oil in Prudhoe Bay, Amer- ica’s largest oil field, not 50 miles from ANWR. The 5,000 original caribou that made up the central arctic herd that mi- grate directly through the center of the oil field has grown and is now over 32,000 animals strong. Some armageddon!
All facilities are elevated to allow caribou to walk un- der them. No facility or pipeline is allowed to be built that will hinder migration. If it is found to do so, it must be re- moved or changed. This is the case throughout the Arctic and would be in the 10-02. Land use in the 10-02 is limited to 2,000 acres—less than 0.05% of ANWR’s area. There is a good chance roads would not be used, and most of the pro- duction facilities already exist at Prudhoe, so few would be needed in the 10-02.
Alaskans find it strange that many Americans have no problem building huge shopping malls to service increasing urban sprawl, laying thousands of miles of roads, running over deer and raccoons every night, everywhere all over the Lower 48, yet on a flat as a pancake stretch of distance coastline in the Arctic with the strictest environmental 24/7 regula- tion on Earth we cannot use 3 square miles of land to sup- ply America with the energy we desperately need.
The 10-02 area is not “pristine.” It is inhabited and hunted and used daily. It is not “special” or “scenic” as the rest (92%) of ANWR is, which is permanently off limits to oil development. It is flat, barren, freezing cold, and wind- swept every day of the year. It is ice covered for 8 months of the year and under total 24-hour darkness for 4 months of the year. Most animal life inhabits the plain only 6 weeks a year in summer when no oil production is allowed.
With the current energy crisis looming we have to take action. Alaskans support this issue and have the knowledge and ability to do this right. From the 10-02 we can supply America with a million barrels of oil a day for decades, pro- viding jobs, security, and growing the national economy. Opening ANWR makes total sense and needs to happen now.
Drilling for Oil in ANWR is a Good Idea Adrian Herrera Adrian Herrera is an analyst for Arctic Power, a private lobby group from Alaska that monitors the ANWR debate on Capitol Hill. He has lived in Alaska 33 years and has worked in the Prudhoe Bay oil fields both as a field hand and as part of the environmental monitor- ing team.
Should We Drill for Oil in the Arctic National Wildlife Refuge?
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Americans have always treasured our wild and special places. Iconic images of the Grand Canyon, Yosemite, and Yellow- stone not only help define our nation and our natural her- itage, they represent our democratic and egalitarian values. Our parks and wildlife refuges have been set aside for all Amer- icans to enjoy and belong to every American and to subse- quent generations. Instead of closing off areas for single uses such as oil and gas drilling or logging and handing lands over to multinational corporations, we work to keep our wild and special places open for everyone to enjoy.
The coastal plain of the Arctic National Wildlife Refuge is one of those wild and special places. The area is America’s greatest wilderness, protecting more abundant and diverse wildlife than any other protected area above the Arctic Cir- cle. The Arctic Refuge supports large populations of caribou, polar bears, musk oxen, and hundreds of migratory birds.
The coastal plain of the Arctic Refuge is also important to the Gwich’in, Alaska Natives whose name means “people of the caribou.” The Gwich’in believe they evolved from the caribou. To the Gwich’in, the Porcupine (River) caribou herd that visits the coastal plain of the Arctic Refuge is sacred and a link to their traditional way of life and subsistence culture. The Gwich’in, along with the Alaskan Intertribal Council, are officially opposed to drilling in the Arctic because of the disruption of caribou migration patterns that would re- sult from drilling threatens their subsistence way of life.
The annual migration of the caribou herd is one of our continent’s most awe-inspiring wildlife spectacles. Each year, the caribou migrate 1,400 miles across Alaska and Canada, typically arriving on the Arctic Refuge in late May where the females give birth. According to some scientists, caribou birth rates could drop by as much as 40% if drilling begins in their habitat.
Unfortunately, oil and gas companies and their pro- drilling allies in Alaska and Washington, D.C. continue to push for drilling in this wild and special place, the vast majority of which is public land shared by all Americans.
Though no one proposes damming the Grand Canyon for hydroelectric power or generating geothermal energy from Old Faithful, oil companies like Exxon and Shell keep pushing for drilling in one of America’s last wild places, the coastal plain of the Arctic Refuge.
Oil drilling would industrialize—and ruin—the Arctic Refuge. One need look no further than Prudhoe Bay in Alaska, one of America’s largest oil fields, to see the damage done by drilling. Prudhoe Bay averages more than 500 oil spills a year—that’s more than one oil spill per day. Four years ago, British Petroleum (BP) had to shut down their entire oper- ation in Prudhoe Bay after they discovered spills caused by corroded pipelines and equipment. BP later revealed that the pipes that leaked had not been inspected in 11 years.
We simply cannot allow that kind of development and damage—and negligence—to occur in an ecosystem as frag- ile and as important as the coastal plain of the Arctic Refuge
We know what drilling will do to the Arctic Refuge— ruin one of America’s wildest and most special places for- ever. We also know what drilling won’t do. It won’t solve our
nation’s energy problems. There is simply not enough oil in the Arctic Refuge to reduce gas prices for consumers or to make America energy independent. At current rates of consumption, oil from the Arctic Refuge could provide at best a few months, not years, worth of energy. And more drilling leads to more burning of fossil fuels, which only accelerates the most press- ing environmental threat of our day: global warming.
It does not make sense to ruin one of America’s last wild places for a short-term supply of oil and gas, especially when we could save much more oil and gas through energy efficiency or by using renewable energy.
It’s time to use America’s technological know-how and innovation to reduce our dangerous dependence on fossil fu- els like oil and gas. Congress took the first step in 2007 when members voted on—and President Bush signed into law—a bill to increase the fuel economy of our cars and light trucks.
In addition to fuel economy, we need to encourage the use of renewable energy like wind and solar power and adopt other existing energy-saving technologies that cut pollution, curb global warming, and create good jobs. Such a strategy will decrease our dependence on oil, reduce pollution, and protect wild places like the Grand Canyon, Old Faithful, and the coastal plain of the Arctic National Wildlife Refuge.
Critical Thinking Questions 1. Summarize each author’s main points and supporting
information. 2. Using your critical thinking skills, analyze each view-
point. 3. Do you agree with one viewpoint? Which one? Why?
The Arctic Refuge: A Wild and Special Place That Should Be Protected for Future Generations Athan Manuel Athan Manuel is the director of the Lands Protection Program for the Sierra Club, where he oversees campaigns to protect public lands, national forests, and parks. He also defends wildlife and the Endangered Species Act and works to stop new offshore oil and gas drilling.
You can link to websites that represent both sides through Point/Counterpoint: Furthering the Debate at this book’s internet site, http://environment.jbpub.com/9e/. Evaluate each side’s argument more fully and clarify your own opinion.
286 PART IV. Resource Issues: Solutions for a Sustainable Society
Coal Coal is a solid organic fuel extracted from mines. It is the most abundant fossil fuel on Earth and is therefore relatively inex- pensive. However, the production and consumption of coal are more environmentally disruptive than for any other major fossil fuel. Significant impacts occur at virtually every step in the process. (Table 14-1 summarizes many of these impacts.)
Impacts of Coal Production: Surface Mining Coal is ex- tracted by surface and underground mines, depending on the terrain and the depth of the seam. In hilly terrain where coal seams lie near the surface, as in the eastern United States, bull- dozers strip the rock and dirt lying over them (the overburden). The overburden is hauled away and eventually replaced after the coal supply has been depleted.
This type of mining is called surface mining, a term that refers to any mine that accesses its mineral from the surface. Several types of surface mines exist. Surface mines that follow the con- tour of the land are appropriately called contour strip mines (FIGURE 14-9). Contour strip mining defaces the landscape. Exposed hillsides can erode during rainy periods if proper precautions are not taken. Contour strip mining in the hilly terrain of Kentucky, for instance, has been shown to increase erosion from 0.4 metric tons per
Coal is the most abundant fossil fuel, but its extraction and use create enormous social, economic, and environmental costs.
hectare (0.18 ton/acre) in undisturbed watersheds to nearly 150 metric tons per hectare (67 tons/acre). Access roads can also erode. During heavy rains, sediment from the roadways washes into nearby streams. Sediment also fills streams, reducing their water-carrying capacity. When rain falls, water spills over the streams’ banks, flooding farms and communities.
Another mining technique in hilly or mountainous ter- rain is mountaintop removal. In this technique, entire moun- tain tops are removed by dynamite and bulldozers to expose coal seams. The overlying material is bulldozed into neigh- boring valleys, causing considerable environmental dam- age. Although it is prohibited by law, this technique was given a boost by the Bush administration in 2002, which rewrote Clean Water Act regulations. The changes make it legal to fill in valleys and streams by such operations. In mountaintop mining, forests are first clear-cut. The rock and dirt over the coal seam is scraped away, destroying all life.
Table 14-1 Major Environmental Impacts of Fossil Fuels
Fuel Extraction Transportation End Uses
Destruction of wildlife habitat, soil erosion from mine sites, sedimentation, aquifer deple- tion and pollution, acid mine drainage, subsi- dence, black lung disease, accidental death Offshore leaks and blowouts causing water pollution and damage to fish, shellfish, birds, and beaches; subsidence near wells Subsidence and explosions
Air pollution and noise from diesel trains
Oil spills from ships or pipelines
Explosions, land distur- bance from pipelines
Air pollution from power plants and facto- ries, especially acid pollutants and carbon dioxide; thermal pollution of waterways
Air pollution similar to that from coal
Fewer air pollutants than coal and oil
FIGURE 14-9 Contour strip mining. Contour strip mining is common in hilly terrain—for exam- ple, in the eastern U.S. coal fields. For many years, overburden was dumped on the downslope, de- stroying vegetation and creating serious erosion problems. Today, overburden is hauled away and stored. When the coal seam is exhausted, the overburden is replaced, graded, and planted.
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Destroying vegetation can lead to flooding and landslides. The overburden is also dynamited to make it easier to remove. Ex- plosions can damage foundations of homes and water wells. “Fly rock” may rain off mountains, endangering resident’s lives and homes.
According to Mountain Justice, a nonprofit that op- poses mountaintop mining, coal companies have buried over 1,920 kilometers (1,200 miles) of biologically crucial Appalachian headwater streams. Although companies are supposed to reclaim the land, this organization claims that “all too often mine sites are left stripped and bare.” (FIGURE 14-10).
In the relatively flat terrain of the West and Midwest, coal is usually mined in area strip mines (FIGURE 14-11a). In this type of surface mine, the topsoil is first removed by scrap- ers and is set aside for reapplication (FIGURE 14-11b). Next, the overburden is dynamited and removed by huge shovels called draglines to expose the coal seam. The coal is re- moved and hauled away, and another parallel strip is cut. The overburden from the new cut is then placed in the pre- vious one (Figure 14-11b). As required by the Surface Min- ing Control and Reclamation Act (1977), the overburden must be regraded to the approximate original contour and the topsoil replaced. Seeds are sown, increasing the likelihood that the area will revegetate.
Area strip mines create eyesores, destroy wildlife habi- tat and grazing land, and may increase erosion. Proper recla- mation can restore wildlife habitat and grazing land and eliminate the visual impact. Surface mines can also disrupt and pollute groundwater supplies in the West because many aquifers are located in or near coal seams. In Decker, Mon- tana, extraction of coal from an aquifer seam resulted in a drop in the water table of 3 meters (10 feet) or more within a 3-kilometer (2-mile) radius of the mine. Some of the residents who depended on the aquifer were forced to drill deeper wells or find new water supplies.
Impacts of Coal Production: Underground Mines In mountainous terrain where coal seams lie deep below the sur- face, coal is extracted via underground mines. Underground coal mines are notorious for explosions and cave-ins, and un- derground coal mining is ranked as the most hazardous of the major occupations in the United States. Between 1900 and 2003, 104,452 Americans were killed in underground coal mines, and approximately 1.63 million were permanently dis- abled. Because of stricter safety regulations, deaths from coal mining have dropped substantially in the last 70 years. The
Coal is removed by surface and underground mines, both of which create many environmental impacts. Surface mining is especially damaging to the environment; proper controls can greatly reduce impacts, though, and mine reclamation can help companies to return lands to their original use.
FIGURE 14-10 Mountaintop coalmine in West Virginia. Mines like this are extremely destructive to the environment and techni- cally illegal, a fact that hasn’t stopped some mining companies from engaging in this damaging practice.
Original ground surface
FIGURE 14-11 Area strip mine. (a) Aerial view of a strip mine. (b) In flat terrain, coal is extracted by strip mining. A dragline removes the overburden to expose the coal seam. Overburden is placed on the previously excavated strip and eventually regraded and replanted. If land is not carefully recontoured and replanted, it could be permanently ruined.
FIGURE 14-12 Black lung disease. (a) Cross-section of a normal lung. (b) Cross-section of a lung from a deceased coal miner who suffered from black lung disease. The black material is carbon from coal dust.
288 PART IV. Resource Issues: Solutions for a Sustainable Society
Bush Administration relaxed many safety standards for un- derground mines. Although we will not know the impact of this action, it is likely that death rates could rise again. In 2006, 47 miners perished in U.S. coal mines. From 2000 to 2009, 311 miners perished in U.S. coal mines. Problems exist in other countries as well. In 2007, a gas leak in an un- derground coal mine killed 35 workers in China. Earlier that year, 181 coal miners died when two coal mines flooded as a result of heavy rains. China’s coal mines average 13 deaths a day as a result of fires, explosions, and floods, largely because of lax safety standards.
Underground coal mines also cause black lung disease, or pneumoconiosis (NEW-moe-cone-ee-OH-sis), a progres- sive, debilitating disease caused by breathing coal dust and dirt particles (FIGURE 14-12). Victims have difficulty getting enough oxygen because the tiny air sacs (alveoli) in the lungs break down. Exercise becomes difficult, and death is slow and painful. Despite safety improvements, one-third of all U.S. underground coal mines still have conditions con- ducive to black lung. Black lung disease kills 1,000 miners a year—that’s three per day. In the United States, there are about 4,000 new cases of black lung disease among coal miners every year.
Collapsing mines also cause subsidence, a sinking of the surface. Cracks form on the surface, ruining good farm- land. In some cases, streams vanish into the fissures. Over 800,000 hectares (2 million acres) of land has subsided in the United States from underground coal mining. For every hectare of coal mined in central Appalachia, over 5 hectares (12.5 acres) of surface becomes vulnerable to subsidence.
Another problem with underground mines is fires. In Pennsylvania, for example, some fires have burned for years, producing considerable amounts of pollution.
Many abandoned coal mines in the East leak sulfuric acid into streams. Acid mine drainage, as it is called, con-
sists of sulfuric acid formed from water, air, and sulfides (iron pyrite) in the mine. A bacterium (Thiobacillus thioxidans) facilitates the conversion, making the wa- ters highly acidic. Acid mine drainage kills plants and an- imals and inhibits bacterial decay of organic matter in wa- ter, allowing large quantities of organic matter to build up in streams. Sulfuric acid also leaches toxic elements such as aluminum, copper, zinc, and magnesium from the soil and carries them to streams.
Acid can render water unfit for drinking and swimming. Municipal and industrial water must be chemically neutral- ized before use. Acid also corrodes iron and steel pumps, bridges, locks, barges, and ships, causing millions of dol- lars of damage each year.
Active and abandoned U.S. mines produce several mil- lion metric tons of acid a year. Acid mine drainage pollutes over 15,530 kilometers (9,709 miles) of U.S. streams, most of which are in Appalachia (FIGURE 14-13). Cleaning up the abandoned mines could take decades and billions of dol- lars, and further increases in coal production could increase acid mine drainage although awareness of the problem has resulted in efforts to reduce it.
Underground mines produce enormous quantities of wastes, which are transported to the surface and dumped near the mouth of the mine. These wastes, called mine tail-
Install energy-efficient light- ing, appliances, and electron- ics to reduce waste heat. This will keep your home cooler in the summer.
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FIGURE 14-13 Acid mine drainage. (a) Map show- ing streams affected by acid mine drainage in the eastern United States. Acid mine drainage is preva- lent in regions where rock contains the sulfur- containing compound known as iron pyrite. (b) Stream severely damaged by acid mine drainage.
Principal coal deposits
Streams affected by acid mine drainage
ings, contain heavy metals, acids, and other pollutants that wash into streams during rains. Coal-cleaning plants, which are designed to crush the coal and wash away impurities, also produce enormous quantities of waste. These wastes are often stored in holding ponds that sometimes leak and pollute nearby streams.
After the coal is extracted, it is loaded onto trucks or rail cars and shipped to power plants. Diesel trains, which move most of the nation’s coal, pollute the air with particulates and other potentially harmful pollutants such as sulfur dioxide.
Impacts of Coal Combustion About 90% of U.S. coal is burned to generate electricity; most of the rest is burned by industry to generate heat or to produce steel and other met- als. Power plants require enormous amounts of coal. For
Underground coal mines present health and safety hazards for miners. Many miners have been killed or injured by accidents. Many others suffer from black lung disease, a crippling degen- erative lung disease, as a result of exposure to coal dust. One of the biggest environmental problems from coal mining results from the release of sulfuric acid from abandoned underground mines, which poisons thousands of miles of streams in the east- ern United States.
example, a 1,000-megawatt coal-fired power plant, which produces electricity for about 1 million people, burns about 2.7 million metric tons (3 million tons) of coal each year. Tens of thousands of tons of pollutants are released into the atmo- sphere during coal combustion, even with pollution con- trol devices in place. These include particulates, sulfur oxides, nitrogen oxides, carbon monoxide, and carbon dioxide. These pollutants are largely responsible for two of the world’s most significant environmental problems, acid deposition and global climate change. They cause billions of dollars in dam- age to fish, lakes, buildings, and human health, as discussed in Chapters 19 and 20.
Coal combustion also produces enormous quantities of solid waste. During combustion, a fine dust known as fly ash is produced. Fly ash is mineral matter that makes up 10% to 30% of the weight of uncleaned coal. It is carried up the smokestack with the escaping gases and, if captured by pol- lution control devices, becomes a hazardous solid waste. Sulfur dioxide gas is also emitted from the stack but can be removed by a pollution control device known as a smoke- stack scrubber (Chapter 19). Scrubbers produce a toxic sludge, containing fly ash and sulfur compounds. Some mineral matter that is too heavy to form fly ash remains at the bottom of the coal-burning furnace as bottom ash. It, too, is a hazardous waste that must be disposed of. Wastes
290 PART IV. Resource Issues: Solutions for a Sustainable Society
from coal-burning furnaces and their pollution control de- vices are generally buried in landfills, but toxic substances from these sites may leak into groundwater supplies, pol- luting them.
A 1,000-megawatt power plant may produce 180,000 to 680,000 metric tons (200,000 to 750,000 tons) of solid waste each year, including fly ash, bottom ash, and sludge from scrub- bers. Coal-fired power plants in the United States annually produce about 109 million metric tons (121 million tons) of solid waste. Approximately 40% of the waste was used to make road surfaces and other products; the rest ended up in landfills.
Oil Shale Oil shale is a sedimentary rock containing a combustible organic material known as kerogen. Oil shale is found in large deposits underlying much of the continental United States, with the richest ones in Colorado, Utah, and Wyoming. Similar deposits are also found in Canada, Russia, and China.
Kerogen can be extracted from oil shale by heat. This process produces a thick, oily substance known as shale oil. Like crude oil, it can be refined to produce a variety of fuels and nonfuel materials.
Oil shale is rather abundant, but its extraction and pro- cessing are energy intensive and therefore rather costly. Net energy analysis, which determines how much energy it takes to extract and process an energy resource in relation to the amount produced, shows that shale oil production creates only about one-eighth as much energy as conventional crude oil extraction for the same energy investment. Its net en- ergy yield (energy produced � energy invested � net energy yield) is therefore rather low.
Oil shale development could result in serious environ- mental impacts as well. Strip mining to remove oil shale would disturb large tracts, causing erosion and reducing wildlife habitat. Mined shale is then crushed and heated in a large vessel, called a surface retort. Surface retorting pro- duces enormous amounts of solid waste, spent shale. A small operation producing 50,000 barrels per day would generate about 19 million metric tons (21 million tons) of waste per year. Since the shale expands by about 12% on heating, not all of it could be disposed of in the mines from which the raw ore came. Dumped elsewhere, the spent shale may be leached by water, producing an assortment of toxic organic pollutants that could contaminate underground and surface waters.
Oil shale retorts require large quantities of water as well, but oil shale deposits are typically found in arid country. Re-
Electric power plants are the major consumer of coal in the United States. Although pollution controls reduce the amount entering the atmosphere, the large number of power plants and the enormous quantities of coal burned in them result in the production of massive amounts of air pollution. Several air pol- lutants contribute to two of the world’s most pressing environ- mental problems—acid deposition and global climate change (global warming). Moreover, pollutants captured by pollution con- trol devices end up as solid waste, much of which is buried in landfills.
torts also produce significant amounts of air pollutants un- less carefully controlled.
To bypass the solid waste problem, oil shale companies once experimented with in situ (IN SEE-two) retorting. In this process, shale deposits are first fractured by explosives. A fire is then started underground in the oily rock and is forced through the deposit. The heat from the fire forces some of the oil out of the rock. The oil is then collected and pumped to the surface.
In situ retorts eliminate many impacts caused by sur- face mining, but they have not worked well because it is dif- ficult to fracture shale evenly (a step needed to promote uniform combustion) and because groundwater often seeps into them and extinguishes the fires.
In the early 1990s, the only oil shale plant operating in the United States, which cost $1 billion to build, closed its doors because it was barely covering operating costs and was producing oil at twice the cost of conventional crude oil.
Today, Shell oil company is experimenting with a new process that they believe could make oil shale development cost-effective. They drill holes in the oil shale and insert elec- tric heaters into them. The oil shale is heated for 2 to 3 years until it reaches 343° to 371°C (650° to 700°F). Oil is released from the rock. It flows into collection wells in the shale and is then pumped to the surface. To contain the oil, they also freeze a large 6 to 9 meter (20 to 30 foot) region around the extraction zone to contain the oil and to prevent water from entering it. Both processes require lots of energy. Although Shell predicts that the final cost will be low, only time will tell. Huge amounts of coal-fired electricity would be needed to run the operation. To develop oil shale, numerous new power plants will need to be constructed and operated in oil shale regions. These plants would require huge amounts of water for cooling towers that would be difficult to obtain in the arid regions in which much of the United States’ oil shale is located.
Tar Sands Tar sands, or oil sands, are sand deposits containing a com- bustible organic material called bitumen. They are another fossil fuel. Although they are found throughout the world, the largest deposits are in Alberta, Canada; Venezuela; and Russia. In the United States, six states have large deposits.
Tar sands are strip mined and then treated with hot wa- ter to extract the bitumen. In situ methods similar to those used in oil shale extraction are also being tested.
Tar sands are plagued with many of the problems that face oil shale. They are expensive to mine. The sand sticks to machinery, gums up moving parts, and eats away at tires
Oil shale is a sedimentary rock containing an organic material (kerogen) that can be extracted from the rock by heating. In a liq- uid state, this thick, oily substance, called shale oil, can be refined to make gasoline and a host of other chemical byproducts. Although it is abundant, oil shale is economically and environmentally costly to produce and is currently an insignificant source of fuel.
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and conveyor belts. Tar sand expands by 30% after process- ing. As with oil shale, its production requires large amounts of water, which becomes badly polluted in the process.
The most significant barrier to tar sand development is a low net energy yield, and thus high cost. At least 0.6 of a barrel of energy is consumed per barrel produced. Worse, world reserves of tar sand oil are insignificant compared with world oil demands. Locally, however, tar sands can make a huge difference. Canada’s oil sands, which is the largest deposit in the world, contain an estimated 1.7 trillion barrels of oil, of which some experts say 300 billion could be recovered. That’s enough to supply Canada at its current oil demand for 200 years. But as noted earlier, oil sands are costly and environmentally damaging. The Canadian govern- ment has poured billions of dollars into research and devel- opment. By 2020, total investment is expected to be about $30 billion. Environmentalists argue that the federal and provincial governments have paid little attention to the po- tential impacts of tar sand development.
Coal Gasification and Liquefaction The abundance of coal in the United States and abroad has stirred interest in coal gasification and liquefication. In both technologies, coal reacts with hydrogen to form synfuels, combustible organic fuels. Coal gasification produces com- bustible gases that can supplement natural gas. Coal lique- faction produces an oily substance that can be refined to make gasoline.
Coal gasification produces numerous air pollutants and requires large quantities of water, making it a dirty alterna- tive to natural gas. The cost of synthetic natural gas is high. An additional problem is the low net energy production. Synthetic gas produced from surface mines is about 1.5 times more expensive than natural gas, and synthetic gas from coal taken from underground mines is 3.5 times more expen- sive.
Coal liquefaction, the production of synthetic oil from coal, is similar to coal gasification. Although there are at least four ways of making a synthetic oil from coal, each in- volves the same general process: adding hydrogen to the coal. The oil produced by liquefaction must be purified to re- move ash and coal particles.
Coal liquefaction could provide liquid fuels, but it would be costly. It produces air and water pollutants and requires large amounts of energy. Like coal gasification, it might be preempted by cheaper, cleaner, and renewable energy sources.
KEY CONCEPTS Coal can be converted to gaseous and liquid fuels to replace oil and natural gas, but the processes are energy-intensive and pro- duce much pollution.
Tar sands are sand deposits impregnated with a petroleum-like substance known as bitumen. Although there are large deposits, they are economically and environmentally costly to extract.
Fossil Fuels: Meeting Future Demand
The sustainability of a fuel source must be judged on the basis of its social and environmental costs as well as its eco- nomic costs. An analysis of supplies is equally important. However, determining how much fossil fuel is available and how long it will last is fraught with difficulties. First, no one knows how much economically recoverable fossil fuel lies within the Earth’s crust. Moreover, some countries have grossly exaggerated supplies, especially oil reserves. Sec- ond, future demand is not entirely predictable. Will the for- mer Soviet Union’s and China’s transformations to capitalistic economies dramatically increase fossil fuel consumption? How much? Will efforts in India, which houses over one-sixth of the world’s people, have a similar effect, greatly increas- ing the depletion of oil and other fossil fuels? Or will the nations of the world adopt energy efficient, renewable tech- nologies on a large scale, cutting energy demand?
This section examines the projected lifetime of three fossil fuels: oil, natural gas, and coal. When examining the prospects for energy supplies, keep in mind the uncertain- ties outlined previously.
Oil: The End Is Near Some experts predict that when the last drop of crude oil has been burned, the world’s oil fields will have yielded be- tween 1,800 and 2,200 billion barrels of oil. This figure is called the ultimate production. About half of this has al- ready been used. So what’s the problem? At the current rate of consumption, all remaining oil would last about 50 years.
The problem is that oil consumption is increasing, on average, approximately 2.5% per year. If oil consumption continues to grow at this rate the remaining oil will be gone much sooner.
Long before the last drop is burned, though, signs of shortage will be evident. You can understand this by study- ing FIGURE 14-14, which shows graphs of petroleum produc- tion in the United States and the world. As illustrated, world oil production is expected to rise to a peak and then begin to fall as reserves are depleted. When? Most experts predict a peak in oil production by 2015. As oil reserves decline, oil compa- nies will have to work much harder to maintain production, which will raise the price of oil considerably. In addition, as domestic oil reserves fall, many nations will turn to the Mid- dle East, which currently houses about two-thirds of the world’s proven oil reserves (FIGURE 14-15). Christopher Flavin and Nicholas Lenssen of the Worldwatch Institute liken the developed world’s dependency on oil to an addiction, note, “Not only is the world addicted to cheap oil, but the largest liquor store is in a very dangerous neighborhood.”
Increasing our dependence on a fuel from a politically volatile region of the world can have devastating conse- quences. For example, the 1973 oil embargo imposed by the Organization of Petroleum Exporting Countries or OPEC and a second embargo by Iran in 1979 drove the price of oil
from $3 a barrel to $34 in a short period, stimulating rapid inflation that brought the industrial world to its knees. The 1991 Persian Gulf War was an- other unfortunate consequence. This war cost several more devel- oped nations $61 billion, a price paid primarily by the United States, Japan, and Saudi Arabia. Many observers believe that America’s military involvement in the Middle East—which has costs hundreds of billions of dollars—is largely due to our desire to secure oil supplies.
Since 2004, oil and gasoline prices have increased dramatically upward as a result of many factors, including rising demand in the United States and China, a lack of oil refinery ca- pacity, and insufficient supply. Some oil analysts pinned much of the blame on insufficient supply—a peak in global oil production.
If demand for oil remains high and continues to outstrip supplies
worldwide, crippling short- ages and exorbitant oil prices and potentially in- flation could all occur. If alternative energy sources are not available, many countries could experience severe economic turmoil: inflation, economic stag- nation, and widespread unemployment. By 2050, oil pro- duction will be a small fraction of current levels.
Can’t we simply find more oil? Although there’s still more oil to find, it’s unlikely that oil companies will make any major new finds to relieve the situation. U.S. oil fields are largely depleted. About 75% of our oil supplies have been used up (Figure 14–14a). World oil supplies are better but we may be at the half way point—that is, we may have con- sumed half of the global ultimate production. But what about future discoveries? Oil companies haven’t found a really large oil deposit since 1962. Of the 40,000 oil fields, only about 40 have been huge. Today, the world consumes about 26.5 billion barrels of crude oil per year, yet annually discov- ers about 4 billion new barrels of oil. Our prospects are not good. Many of the world’s large oil fields are on the decline. As Table 14-2 shows, oil production has already peaked and is now declining in many countries such as Mexico, Iran, and Russia. Even the mammoth oil fields of Saudi Arabia are thought to have peaked.
Rising fuel prices could stimulate a massive shift to- ward energy efficiency—for example, new more efficient vehicles such as the gas-electric hybrid Toyota Prius, plug- in hybrids, and electric cars (FIGURE 14-16). To prevent wide- spread economic turmoil, however, nations must act soon to use oil more efficiently and to find replacements for oil—
Ultimate production: 225–250 � 109 barrels total
ua l p
0 1920 1900
1940 1960 1980 Year
2000 2020 2040
Ultimate production: 2200 � 109 barrels total
ua l p
0 1925 1900
1950 1975 2000 Year
(a) United States
2025 2050 2100 2075
FIGURE 14-14 The fate of U.S. and global oil supplies. Petro- leum production curves for (a) the United States and (b) the world. U.S. oil production has already peaked. The oil derricks rep- resent the increasing cost of drilling to extract declining supplies.
Proved reserves at end 2007 Thousand million barrels
111.2 117.5 143.7
South & Central America
Africa Europe & Eurasia
FIGURE 14-15 Where will the industrial countries get their oil? This map shows where the world’s oil lies. (Reproduced from the BP Statistical Review of World Energy, 2008. Used with per- mission of BP.)
To save energy, slow down. Driving 65 miles per hour uses about 12.5% more gasoline than driving 55 mph. Driving 75 mph uses 25% more fuel than driving 55 mph.
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which powers our transportation system, heats some of our homes, and provides the raw materials for asphalt, plastics, medicines, cosmetics, and much more. Some energy options are discussed in Chapter 15.
Natural Gas: A Better Outlook The outlook for natural gas is brighter than the outlook for oil. For the time being, it appears that global supplies are ade- quate. In the United States, however, natural gas supplies are running low. (FIGURE 14–17). As illustrated in Figure 14–17,
Global oil supplies appear to be quite large; however, when one calculates how long they will last (based on the historical in- creases in energy consumption), it appears that oil supplies may last only 20 to 40 years. Long before the last drop of oil is removed, however, oil production is likely to peak, resulting in widespread shortages and rising prices that could have serious social and economic repercussions.
Table 14-2 Selected Nations in Which Oil Production Has Peaked
Country Year Oil Production Peaked
United States 1970 Iran 1973 Russia 1988 Indonesia 1994 United Kingdom 1999 Norway 2001 Mexico 2004 Source: Association for the Study of Peak Oil
FIGURE 14-16 Toyota Prius, Gen II. This five-passenger car owned by the author is the second generation of the world’s first mass-produced gasoline-electric hybrid vehicle. This car is pow- ered by a gasoline-fueled internal combustion engine and a clean, quiet electric motor. Its low emissions earn its title as a super ultra-low-emission vehicle.
Year 1980 19851970 19751965 2005 20101995 200019901955 19601945 19501940
US production peaked in 1973
Production generally flat since 1994
FIGURE 14-17 U.S. marketed natural gas production from gas wells, oil wells, and coal bed wells, 1930–2009. Adapted from U.S. Energy Information Administration, U.S. Natural Gas Withdrawals.
natural gas production peaked in 1973, declined, then plateaued for many years. As you can see from the graph nat- ural gas production has risen in recent years. This largely is due to a dramatic increase in gas drilling. The number of wells has increased 342,000 to 468,000 from 2000 to 2009. Some relief may result from natural gas found in the Marcellus For- mation in the eastern U.S., mentioned earlier. This rock is a black, low density, organic rich shale that occurs beneath much of Ohio, West Virginia, Pennsylvania, and New York. Small areas of Maryland, Kentucky, Tennessee, and Virginia are also underlain by the Marcellus Shale. All locations are close to major population areas.
Some estimate that huge amounts of natural gas can be extracted from these deposits. Some geologists project that the Marcellus might contain more than 14.5 trillion cubic meters (500 trillion cubic feet) of natural gas. Using some of the same methods that had previously been applied to shale deposits in Texas, it is estimated that 10% of that gas or 1.4 trillion cubic meters (50 trillion cubic feet) might be economically recover- able. Although that sounds like a lot, this would only be enough to supply the entire United States for about 2 years.
Because global natural gas supplies are relatively large and because it is a clean-burning fuel that can be used in cars, power plants, industry, and homes, many believe that natural gas could replace the more environmentally dam- aging fossil fuels, oil and coal. In fact, sustainable energy proponents believe that natural gas is a great transition fuel. It will help wean us from coal and oil, the most environ- mentally unsustainable fossil fuels, and provide us time to develop a sustainable energy system based on conservation and renewable energy sources (Chapter 15).
There are problems however, with this strategy, as much of the world’s remaining natural gas supplies are in the Mid- dle East. Domestic supplies are on the decline, causing prices to skyrocket. (They tripled from 2000 to 2004.) Can’t we merely import more?
Natural gas must be compressed and shipped by tanker. Today, the United States imports only 2% of its natural gas this
FIGURE 14-18 Structure of the atom. Atoms consist of a dense central region, the nucleus, containing protons and neutrons. Electrons are found in the much larger electron cloud, which sur- rounds the nucleus.
10 _10 m
10 _15 m
Nucleus (protons and neutrons)
294 PART IV. Resource Issues: Solutions for a Sustainable Society
way and is not equipped to handle much more. Increasing im- ports would require numerous ports to develop facilities to handle ships and highly explosive gas, and many cities have rejected plans to do so. Even if we could, some experts pre- dict that global natural gas production will peak between 2015 and 2025.
Coal: The Brightest Outlook, the Dirtiest Fuel Coal is the world’s most abundant fossil fuel. Geologists esti- mate that the world’s recoverable coal reserves are around 800 or 900 billion tons or gigatons. While that seems like a lot of coal, at the current extraction rate, coal reserves would last only 132 years. The rate of coal consumption has been at 2 to 3% per year for many years. If the rate continues at 2.5% per year, the world’s recoverable coal reserves will last 56 years—within the lifespan of most readers.
The United States has 27% of the world’s coal supplies. Recoverable coal reserves are estimated to be about 263 bil- lion short tons (a short ton is 2,000 pounds) or 237 billion metric tons. The U.S. consumes about 120 million short tons a year. At that rate, U.S. coal supplies will last over 2,000 years. In addition, geologists believe that the U.S. has another 226 billion short tons (203 billion metric tons) that could be recovered. Together, U.S. coal supplies could last a very long time, even at increased levels of consumption.
Although growth rates in use would greatly reduce the life span of coal, the large supply suggests that coal could be with us for many years to come. Unfortunately, evidence strongly suggests that coal is an environmentally unsustain- able fuel. In fact, with the exception of oil shale, coal is the dirtiest of all fossil fuels. Its combustion produces enormous amounts of ash, toxic sludge, particulates, and gaseous air pollutants. Although cleaner and more efficient ways to burn coal are being developed, progress has been slow. As you will learn in Chapter 19, air pollution control technologies and new clean-coal technologies do little to prevent one of the world’s most potentially troubling environmental prob- lems: global climate change caused in large part by carbon dioxide emissions from fossil fuel burning facilities, especially coal-fired power plants.
Nuclear Energy Nuclear energy provides a growing percentage of the world’s energy demands. In Canada, for instance, nuclear power provides approximately 7% of the total energy. In the United
Coal supplies in the United States and many other countries are abundant, but evidence suggests that coal combustion is an environmentally unsustainable fuel.
Natural gas is a clean and rather abundant fossil fuel that could provide a source of energy as the world makes the transition to a more sustainable energy supply system.
States, it satisfies 8.5% of our total energy demand. The nu- clear reactors in use today in most nuclear power plants are fueled by naturally occurring uranium-235 (U-235). To un- derstand how nuclear fuel works and some of its dangers, you must understand the atom and radioactivity.
Atoms: The Building Blocks of Matter All matter is composed of tiny particles called atoms. Atoms, in turn, join to form molecules. The atom is composed of two parts: a centrally placed nucleus and an electron cloud (FIG- URE 14-18). The nucleus contains two tiny subatomic par- ticles, protons and neutrons, and constitutes 99.9% of the mass of an atom. Protons are positively charged particles. Neu- trons have no charge.
Encircling the nucleus is a comparatively large area, the electron cloud. It contains much lighter particles of an atom, the electrons. These negatively charged particles orbit around the positively charged nucleus. To give you an idea of the rel- ative size of the electron cloud and nucleus, a simple anal- ogy will suffice. If an atom were the size of Mt. Everest (about 8,800 meters or 29,000 feet), the nucleus would be about the size of a football. The rest of the atom would be made of the electron cloud.
Radioactive Atoms If you have ever studied chemistry, even a brief course in high school, you learned that atoms form elements, such as carbon, nitrogen, gold, and uranium. An element is the purest form of matter. Each element contains one type of atom. Pure carbon, for instance, contains only carbon atoms. Pure gold contains only gold atoms. Even so, not all atoms in an element are identical. Although carbon contains only
Atoms are the building blocks of all elements. All atoms consist of positively charged nuclei, containing protons and neutrons, surrounded by large electron clouds in which the negatively charged electrons are found.
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carbon atoms, some carbon atoms are slightly different from others. These differences are small. They don’t affect the chemical properties of the atoms, that is, how they react, but they can have profound consequences that cause some atoms to emit radioactivity.
How do atoms differ? Although all atoms of a given el- ement contain the same number of protons in their nuclei, some contain slightly different numbers of neutrons. For example, all uranium atoms contain 92 protons, but some have 146 neutrons and others 143. These alternate forms are called isotopes. To distinguish one isotope from an- other, scientists add up the protons and neutrons and tack the sum of these two onto the name of the element. For ex- ample, the isotope of uranium that contains 146 neutrons is called uranium-238 because it contains 92 protons and 146 neutrons.
Excess neutrons in some isotopes make them unstable. To reach a more stable state, they emit radiation, high- energy particles or bursts of energy. Unstable, radioactive nuclei are called radionuclides (ray-de-oh-NEW-klides). They occur naturally or can be produced by various physical means. For the most part, the naturally occurring radionuclides are isotopes of heavy elements, from lead (82 protons in the nucleus) to uranium (92 protons in the nucleus).
Radiation Radionuclides emit three types of radiation: alpha particles, beta particles, and gamma rays. Alpha particles are the heav- iest of the three forms of radiation. Each alpha particle con- sists of two protons and two neutrons, the same as a helium nucleus. Alpha particles are positively charged because they contain protons.
Because alpha particles have the largest mass of all forms of radiation, they travel only a few centimeters in air. They can easily be stopped by a thick sheet of paper, so it is easy to shield people from this form of radiation. In the body, al- pha particles can travel only about 30 micrometers (30 mil- lionths of a meter, or about the width of three cells) in tissues. They cannot penetrate skin and are therefore often erro- neously assumed to pose little harm to humans. But if alpha emitters enter body tissues—say, through inhalation—they can do serious, irreparable damage to nearby cells and their chromosomes.
Beta particles are negatively charged particles emitted from nuclei. They are equivalent to electrons, except they are more energetic. Beta particles are ejected from nuclei when neutrons in the nucleus are converted into protons, a process that helps stabilize radionuclides.
The beta particle is much lighter than the alpha particle and can travel much farther. It can penetrate a 1-millimeter
Elements are the purest form of matter. Although all atoms of a given element are the same type, some atoms contain slightly more neutrons. Those atoms with excess neutrons tend to be un- stable and often emit radiation.
lead plate and can travel up to 8 meters (27 feet) in air, but only 1 centimeter (0.4 inch) in tissue. Beta particles from some radionuclides have enough energy to penetrate clothing and skin but generally do not reach underlying tissues. They can, however, damage the skin and eyes (causing skin can- cer and cataracts).
Gamma rays are a high-energy form of radiation with no mass and no charge, much like visible light but with much more energy. Gamma rays are emitted by nuclei to achieve a lower-energy, more stable state. They are often emitted after a nucleus has ejected an alpha or beta particle because even the loss of these particles does not always al- low the nucleus to reach its most stable state. Some gamma rays can travel hundreds of meters in the air and can easily penetrate the body. Some can penetrate walls of cement and plaster or a few centimeters of lead.
Another common form of radiation is the X-ray. Unlike the three previously discussed forms, X-rays do not origi- nate from naturally occurring unstable nuclei. Rather, X-rays are produced in X-ray machines. An X-ray machine con- tains a source of electrons, which are emitted when the ma- chine is turned on, and a tungsten collecting terminal in a vacuum tube (FIGURE 14-19). Electrons strike the collecting terminal or target, collide with tungsten atoms, and are then rapidly brought to rest. The energy they carried in is re- leased in the form of X-rays, which behave like gamma rays but have considerably less energy. Because of this they can- not penetrate lead.
All the forms of radiation described above are called ionizing radiation because they possess enough energy to rip electrons away from atoms, leaving charged atoms called ions. Ions are the primary cause of damage in tissues. Ion- izing radiation differs from electromagnetic radiation such as radiowaves and magnetic fields, which are weak and un- able to ionize materials.
KEY CONCEPTS Physicists have identified three major types of ionizing radia- tion released by radioactive atoms: alpha particles, beta parti- cles, and gamma rays. They vary in mass and ability to penetrate. All can cause electrons to be removed from molecules they strike. The X-ray is an artificially produced form of radiation that resem- bles the gamma ray.
– + Electrons Target
FIGURE 14-19 Anatomy of an X-ray machine. Electrons strike a tungsten filament (red), causing it to release high-energy X-rays.
FIGURE 14-20 Nuclear fission. (a) In a fission reaction a uranium-235 nucleus struck by a neutron splits into two smaller nuclei. Neutrons and enormous amounts of energy are also released. (b) A chain reaction is brought on by placing fissile uranium-235 into a nuclear reactor. Neutrons liberated during the fis- sion of one nucleus stimulate fission in neighboring nuclei, which in turn release more neutrons. Thus, the chain reaction can be sustained.
(b) Chain reaction
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Fission Byproducts When a U-235 nucleus splits, it pro- duces two smaller nuclei, called daughter nuclei or fis- sion fragments (Figure 14-20). Over 400 different fragments can form during uranium fission, many of them radioactive. When U-235 nuclei split, they also release neutrons, which strike other nuclei in the fuel rods, creating a chain reac- tion. However, the chain reaction is controlled to keep it from producing so much heat that the reactor core melts. (An atomic explosion in such a case would be unlikely be- cause the fuel is not sufficiently concentrated.)
How a Nuclear Reactor Works Nuclear fuel is extracted from naturally occurring uranium ore. Uranium ore is a mixture of uranium-235, which is fis- sionable, and uranium-238, which is not. In the United States, most uranium ore is found in the western states such as Colorado and Utah.
To create fuel for nuclear power plants, fuel enrichment plants first concentrate the uranium-235 to about 3%. The enriched fuel, called yellow cake, is then formed into pellets. These are inserted into thin, stainless steel tubes, the fuel rods. About 4 meters (12 feet) long and about 1.2 centimeters (0.5 inch) in diameter, fuel rods are bundled together, with 30 to 300 per bundle. They can then be lowered into the core of the reactor (FIGURE 14-22).
Understanding Nuclear Fission With this background material, we continue our explo- ration of nuclear energy. As noted earlier, nuclear fuel con- tains U-235. Nuclear fuel does not burn like fossil fuels, but rather undergoes fission. Fission is the splitting of atoms. Atoms don’t split spontaneously, though. Rather, in- side a nuclear reactor U-235 atoms undergo fission when they are struck by neutrons. When they split, uranium atoms give off enormous amounts of energy (FIGURE 14-20). In fact, the complete fission of 1 kilogram (2.2 pounds) of U-235 could yield as much energy as 2,000 metric tons (2,200 tons) of coal!
Atomic fission takes place inside special devices, fission reactors, designed to contain the energy and radioactivity re- leased during fission. As illustrated in FIGURE 14-21, U-235 is housed in long fuel rods that are located in the reactor core. U-235 atoms naturally emit neutrons that bombard other ura- nium atoms, causing them to split. The heat released during fission is then transferred to water that bathes the fuel rods in the reactor core. As Figure 14-21 shows, the heated water around the reactor core heats water in another closed system. In the latter, hot water is converted to steam, which drives a turbine that generates electricity. The steam is then cooled and the water is used again. Most nuclear plants are cooled by water and are called light-water reactors (LWRs).
The reactor core provides a site where nuclear fission can occur and be carefully controlled to avoid a meltdown. Bathed in water, which draws off heat from the nuclear fission reac- tions, the reactor core is housed in a large reactor vessel (Figure 14-22). It is made from 15-centimeter (6-inch thick) steel (Figure 14-22).
In most countries, the reactor vessel is usually further housed in a containment building, a domelike structure with 1.2-meter (4-foot) walls of concrete (FIGURE 14-23). Its function is to contain the radiation in case the reactor ves- sel or pipes rupture. Unfortunately, not all reactors have complete containment buildings. The nuclear reactor at Chernobyl (described in the text) had only a partial con-
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FIGURE 14-21 Anatomy of a pressurized nuclear power plant. As shown here, nuclear fission reactions in the reactor core heat up water to generate steam. The steam runs a turbine that generates elec- tricity, as in conventional power plants. The water surrounding the reactor core circu- lates in a closed system. Heat is transferred to another closed system that generates steam. This double water-heating system helps prevent the escape of radioactivity from the system.
Primary water system Secondary water system
Steam line Turbine generator
FIGURE 14-22 The interior of a nuclear power plant contain- ment building. The reactor core is in the middle of the contain- ment vessel, under 10.7 meters (35 feet) of water.
FIGURE 14-23 The containment building of a nuclear power plant.
tainment building, which proved entirely inadequate in 1986 when the reactor melted down. Twenty of the former Soviet Union’s 44 reactors now in operation have the same design.
The intensity of the nuclear chain reaction is controlled primarily by neutron-absorbing control rods. By absorbing neutrons, they limit the rate of fission. Frequently made of cadmium or boron steel, the control rods fit in between the fuel rods and can be raised or lowered to control the rate at which fission takes place. They are also used to start and stop a reactor. Raising them, for instance, starts the chain