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Introduction Fossil Fuels: Oil & Gas Fossil Fuels: Nuclear Energy Alternative Energy Resources Summary

At the heart of modern society lies an economy driven by energy use. Unfortunately, the same energy that brings us comfort, convenience, and prosperity also brings us pollution, impoverishment, and global warming. Our challenge is to maximize the benefits gained from energy consumption while minimizing the costs incurred. Douglas Foy

A fuming smokestack is the perfect symbol of our national dilemma. On the one hand, it means the jobs and products we need. On the other, it means pollution. American Gas Association ad, 1991 Introduction

• Fossil fuels (oil, gas, coal) makeup most of the energy consumed in the U.S. • Energy use increases with increasing , area, and industrial activity and energy use per capita is greatest in large, sparsely populated states. • Fossil fuels are non-renewable resources with limited life span and their combustion contributes to global warming. • Alternative energy sources such as solar and wind power are renewable and hold the promise of a future.

U.S. Energy Use Current U.S. energy use is weighted heavily toward fossil fuels (oil, natural gas, and coal) that account for approximately 90% of all energy used in the nation (Fig. 1). Environmental concerns over air pollution and the potential for global warming may encourage wider access to alternative energy sources such as and wind or solar energy. Nuclear power accounts for about a fifth of U.S. electricity generation but only 5% of total energy consumption. Alternative energy sources (hydroelectric, wind, solar, geothermal) generate 5% of U.S. energy production but may expand that share in the decades ahead.

Energy use within the U.S. varies with population size and character of energy demand (Fig. 2). States with large , large land area (greater distances to travel), and

Figure 1. U.S. energy consumption per energy type, 1949 to 1995. Graph courtesy of the Energy Information Administration.

2 energy-intensive industries (e.g., oil refining, chemicals), typically use the most energy. Large sparsely populated states such as Wyoming and Alaska rate highly in energy use per person because transportation consumes large volumes of fuel.

Fossil fuels form from decayed organic material through a series of chemical reactions that occur gradually over millions of years under specific physical conditions in a select group of rocks. These conditions make it possible to predict where oil and gas may be found but also highlight the fact that fossil fuels are non-renewable resources that will not be replaced once used. Reserves of oil and natural gas will probably be stretched out for another century but we must face the inevitable conclusion that these finite resources will have to be replaced with an alternative form of energy in the next 50 years. The inevitable decrease in the availability of fossil fuels will be felt most acutely in transportation because there is no viable inexpensive replacement for the refined petroleum products that fuel automobiles and airplanes.

Figure 2. Distribution of U.S. energy use. Energy use at home and is typically in the form of electricity generated by burning coal. Transportation is almost exclusively Coal represents an alternative fossil fuel with a potentially fueled by forms of longer life span than either oil or gas but it has the unfortunate refined from distinction of generating more pollution than the other fossil petroleum. fuels. Furthermore, coal produces more during combustion than either oil or gas, but all three have been fingered as the primary sources of the that is the culprit for global warming.

Advocates of a nuclear future have seized the potential threat of global warming and the nation's dependence on foreign oil to advance the nuclear cause. Fifty years ago, scientists working in the fledgling U.S. nuclear power industry (Fig. 3) predicted that electricity would be virtually free by the end of the century because of the electrical benevolence of nuclear energy. Today, only 17% of the world’s electricity is generated by nuclear power and that number is unlikely to grow because of concerns about the safety of nuclear reactors and anxiety over how to dispose of highly radioactive produced

3 during power generation. Rarely has a shown such early promise only to fall so rapidly from grace.

Alternative energy resources (hydroelectric, wind, solar, biomass, geothermal) generate less than 10% of U.S. energy but have few of the drawbacks of fossil fuels or nuclear power and hold promise of a sustainable energy future. A veritable chorus of Pollyannas has sung the praises of alternative energy since the 1970s but their potential remains ambiguous because of uncertainties over the rate of technological development and operating costs. Some of these sources have greater potential than others with solar energy and wind power Figure 3. Perry holding the most hope for the future. nuclear reactor, 35 miles northwest of The industrial air pollution that was once proudly viewed as a , Ohio. by-product of economic growth is now largely a thing of the is on the past. No longer will thousands of people die during a weekend left of the image. of lethal air pollution as they did in in 1952. Air Image courtesy of the Nuclear Regulatory pollution is still widespread but its effects are muted, hidden Commission (NRC). among reports of greater incidence of and other respiratory ailments and studies of downwind from industrial centers. The burning of fossil fuels represents a major source of air and cleaner air will therefore be an indirect by-product of any change in energy production in the years ahead.

Think about it . . . 1. Predict which of the following states consumes the most energy. a) California b) Illinois c) New York d) Texas 2. Examine the partially completed graph found at the end of the chapter that plots gross domestic product (GDP) per capita vs. energy consumption per capita. Label the points that represent where you think the eight named nations would plot on the graph. 3. Draw a time line for energy use before you read any further in this chapter. Label the time line to indicate how energy consumption has changed/will change from 1850 to 2050. Differentiate between domestic and industrial energy sources and transportation energy sources.

4 Fossil Fuels: Oil & Gas

• Time and a specific range are necessary for the generation of oil and gas. • As become mature they progress from heavy oils to light oils to natural gas. • Hydrocarbons become concentrated in sedimentary rocks. • The volume of the world’s oil reserves is approximately 1,070 billion barrels. • The U.S. uses 25% of the world’s oil. • Two-thirds of the world’s oil reserves are located in the Middle East.

Fossil fuels form from decayed organic material. Oil, coal, and natural gas are the most common products of this process. Oil and gas form from organic material in microscopic marine , whereas coal forms from the decayed remains of land plants. Tar (oil) sands and oil shale are less common forms of fossil fuels and are less widely used because extraction of oil from these deposits is more expensive than producing other forms of fossil fuels.

Generation and Production of Oil and Gas The two principal requirements in the generation of oil and gas (also known as hydrocarbons - chemical compounds of carbon and hydrogen) are time and a specific range of temperature. The steps in the process are: 1. Organic-rich sediments are deposited and gradually buried to greater depths and converted to sedimentary rock (e.g., shale). 2. Chemical reactions occur during burial under conditions of increasing temperature and pressure. The reactions occur at of 50 to 100oC, higher temperatures "boil off" the hydrocarbons; lower temperatures are not sufficient to drive the chemical reactions. 3. The reactions change the organic molecules to molecules. With increasing time (millions of years) the hydrocarbons become more mature changing from heavy oils to lighter oils to natural gas. Fossil fuels are considered

5 non-renewable resources because they are consumed much faster than they can be replaced.

Oil and gas migrate upward through fractures and pore spaces in permeable rocks and/or sediments. Some hydrocarbons escape at ’s surface through features such as oil seeps. Others collect below the surface in sedimentary rocks when their path is blocked by low-permeability rocks (Fig. 4). Rock structures such as faults and folds may serve to juxtapose permeable and impermeable units. Oil and gas are trapped in the permeable rocks and will migrate upward to lie at the highest elevation in the rock unit.

Figure 4. Oil and gas will migrate through permeable rocks to the highest available elevation. Examples of traps include folds (left), and faults When an oil field is first drilled the oil is driven into the well (right). by pressures within the rocks. This primary recovery will extract about 25% of the oil. Additional oil can be extracted using enhanced recovery techniques that make it easier for the oil to enter the well. Such techniques may include artificially fracturing the rock to create passages for oil migration or pumping wastewaters from drilling operations into nearby wells to drive the oil toward the producing well.

Oil Reserves Oil and gas are not distributed uniformly within Earth's crust (Fig. 5). Hydrocarbons are initially formed as organic-rich sediments and the oil and gas subsequently migrate upward, into younger rocks that are also of sedimentary origin. Consequently, oil and gas reserves are generally absent in areas underlain by igneous or metamorphic rocks such as volcanic island chains like Japan or Hawaii. Even in areas where sedimentary rocks are present, they must fall within a specific age range to ensure that the rocks are mature enough to contain hydrocarbons but not so old that oil and gas would have long ago escaped.

Oil reserves steadily increased since the first commercial oil well was drilled in Titusville, Pennsylvania, in 1859 but estimates of global reserves have remained relatively uniform

6 Figure 5. Locations of at around a billion barrels over the last decade. Oil reserves principal North American oil fields remained stable despite the fact that global population has (left) and other doubled in the last thirty years. Reserves haven't declined hydrocarbon because of: resources (right). • Exploration of geologic formations in increasingly remote Most oil shales and areas of the world, including the seafloor, using an array of oil sands are not new methods that utilize and geophysical economically viable now but may play a instruments to unravel the geology in regions where few more significant role rocks are visible. in energy production • Improved technology used by oil companies to extract as supplies decrease. greater volumes of oil through enhanced recovery techniques. • Greater efficiency in energy use as a result of higher fuel prices and stricter pollution standards that caused manufacturers to build more energy-efficient appliances and engines.

Further improvements in energy efficiency will continue to delay the inevitable decline in oil reserves. For example, recently introduced combination gas-electric can be driven 112 km (70 miles) on a gallon of gas. However, even with the best management and environmental stewardship we must anticipate that a world that continues to rely on oil will see this finite resource decline toward the second half of this century.

Known world oil reserves are approximately 1,030 billion barrels (one barrel is equivalent to 42 gallons). These reserves would last for nearly 40 years at current global consumption

7 rates. The U.S. Geological Survey recently issued a more optimistic estimate that there actually may be double those reserves left to be discovered with a potential life span until the end of this century.

The U.S. uses 25% of the world's oil, much more than any other nation, and imports over half of the oil it consumes. Consequently we are vulnerable to disruptions in oil supplies. Current fluctuations in gasoline prices that result from relatively modest changes in supply and demand will become much more exaggerated as the available reserves of oil decline. The future success of the U.S. economy may rely on the state of our political relationships with the relatively few nations that have abundant oil reserves.

Figure 6. Distribution of global oil and gas reserves expressed as a percentage of global reserves. Two- thirds of the world’s oil and one-third of all natural gas reserves are located in the Middle East. Russia has 33% of the world's natural gas and Saudi Arabia has 25% of the world's oil.

The majority of the oil and other petroleum products currently imported into the U.S. come from just four nations, Venezuela, Mexico, , and Saudi Arabia. However, as two-thirds of all the world's oil reserves are located in the Middle East (Fig. 6), countries such as Saudi Arabia, Kuwait, Iran, and Iraq may play an increasingly important role in U.S. oil supply in the decades ahead.

Think about it . . . 1. Use the Venn diagram found at the end of the chapter to compare and contrast the similarities and differences between the characteristics of oil and coal resources.

. . . continued on next page

8 2. Similar organic-rich source rocks are present in two locations. Oil deposits formed in the overlying rocks at the first location but did not form at the second location. Which of the following is the best explanation for this difference? a) The first location was more deeply buried than the second. b) The first location was subjected to lower temperatures than the second. c) The first location contains younger rocks than the second. d) Rocks at the first location had lower permeability than rocks at the second site.

Fossil Fuels: Coal

• The carbon content and heat content of coal increase with increasing maturity. • The volume of ash residue after burning decreases with increasing coal maturity. • The two principal regions of coal production in the U.S. are the Appalachian basin and the Great Plains. • Sulfur content of coal is lower in the Great Plains and higher in the Appalachian basin. Figure 7. Progression • Air pollution, medical expenses, and fees are of coal rank (maturity) external costs of coal use. from carbon-poor peat to carbon-rich Coal, the carbon-rich residue of plants, can be classified by anthracite. The rank or carbon content. Coal matures by increasing rank with relative proportion of increasing burial pressure (Fig. 7). U.S. coal production by rank is anthracite 2%, bituminous 53%, sub-bituminous 36%, and lignite 9%.

9 Peat is the least-mature form of coal, containing a large volume of fibrous plant matter. With increasing compaction, water is driven out and carbon becomes increasingly concentrated. Both carbon content and the amount of heat released during burning increase with maturity. The carbon content ranges from around 30% in peat to 99% for anthracite. The higher the carbon content, the more heat that is released when the coal is burned. Small amounts of high-carbon produce the same heat as large volumes of low-carbon coal. The volume of ash that remains after burning decreases with increasing rank. The Figure 8. Coal- bearing areas of the ash must be disposed off in a landfill thus increasing expense. U.S. Image courtesy of Energy Information Administration.

10 There are three principal coal-producing regions in the U.S. (Fig. 8). The first two, Appalachian basin states (Ohio, eastern Kentucky, West Virginia, Pennsylvania) and interior states (Illinois, Indiana, western Kentucky) produce high-rank bituminous coals and anthracite. These coals are produced from both surface and underground mines. Unfortunately, some of the bituminous coals have a high sulfur content (Fig. 9) and therefore contribute to air pollution. Given the stringent on pollutants, some companies prefer to use lower- grade sub-bituminous coals to avoid costs associated with installing pollution control devices.

Figure 9. Comparison of sulfur content and heat content of coals from principal U.S. coal-producing regions. Western coals have less sulfur and lower heat content.

Great Plains and Rocky Mountain states (Montana, Wyoming, North Dakota, South Dakota, Colorado) produce lignite and sub-bituminous coals from surface mines (Figs. 8, 10). These coals may occur in especially thick seams making the process much less expensive than for underground mines. Larger volumes of these lower-grade coals must be burned to generate the same heat as bituminous coal or anthracite. Companies pay more to haul the extra coal but save money on production and labor costs. Sub-bituminous coals were not heavily mined prior to 1970. Subsequent to that date surface mines have produced more coal than underground Figure 10. Thick mines and the western coal production has steadily risen to a seam of sub- bituminous coal in the Powder River basin, northeast Wyoming. This seam is 60 meter (200 foot) thick for much of its length and is less than 15 meters(50 feet) below the surface at this location.

11 point today where coal production is approximately equal east and west of the Mississippi River (Fig. 11).

Figure 11. Principal coal reserves of the U.S. Lower map shows top-10 states for coal reserves that can be divided between lignite and sub-bituminous coals in the West, and mainly bituminous coals and anthracite east of the Mississippi River.

Air pollution represents one of the external costs associated with the combustion of fossil fuels. External costs are the price we pay indirectly - in taxes, , medical bills, landfill fees - because of the use of fossil fuels. The use of coal would become less economically attractive if these costs were applied to the original (internal) cost of coal. Electric account for approximately 90% of all U.S. coal consumption and are the major source of nitrogen dioxide and , two key air pollutants.

The most potentially significant external cost of using fossil fuels is the build up of carbon dioxide in Earth's atmosphere. Scientists predict that fossil fuel emissions will to a warmer "greenhouse" world, initiating a potential cascade of negative economic repercussions. Consequently, future energy policy may not be concerned with how much fuel is left, but may instead focus on how to use it without prompting changes in global climate.

Coal Reserves Over 80% of the world's recoverable coal is found in just seven nations (Fig. 12). The U.S. has the greatest reserves, accounting for 25% of the world's coal, enough to last for 270 years at current consumption rates. This suggests that we will have a plentiful supply of electricity into the distant future but it is of little help as a replacement fuel for refined oil products (gasoline) unless we can assume that automobiles of the future

12 Figure 12. The U.S. has a quarter of the world's available coal reserves and 83% of all reserves are divided among just seven nations.

will run, at least partially, on electricity. Even in this scenario, we are still left with the potential for additional air pollution and the threat of global warming.

Think about it . . . 1. Use the Venn diagram found at the close of the chapter to compare and contrast the characteristics of oil and coal resources. 2. Examine the map of U.S. coal resources found at the end of the chapter and predict where the five numbered points on the graph of sulfur content vs. BTU might plot on the map.

Nuclear Energy

• Nuclear reactors generate 17% of the world’s electricity and 5% of total energy. • Nuclear power has fallen from favor because of accidents like Three Mile Island (1979) and Chernobyl (1986). • There are over 100 operating nuclear reactors in the U.S., approximately a quarter of all nuclear power plants worldwide. • The benefits of nuclear energy are: no air pollution, no greenhouse effect, and a reduction in dependence on foreign oil.

13 • The potential problems are: U.S. reactors are getting old and there is no currently available site for permanent nuclear waste disposal. • A potential storage site for nuclear waste is being investigated at Yucca Mountain, Nevada. • The Yucca Mountain site is isolated, has a dry climate, in rocks with low porosity and permeability, and is located far above the groundwater table. However, the area around Yucca Mountain has experienced earthquakes and volcanism.

Approximately 17% of the world’s electricity is generated by nuclear power but that represents only 5% of the world’s consumption of energy. Clearly there is room for improvement. Current concerns about global warming have caused some governments to give nuclear energy another look and has increased optimism within the nuclear power industry prompting a series of ads that tout nuclear energy as the environmentally friendly alternative to dirty fossil fuels. Most evolve into increasingly sophisticated and cheaper forms following their introduction and will continue to grow in popularity until they are replaced by a better alternative. Not so nuclear power. After a meteoric rise, the nuclear power industry hit a wall in the latter part of the last century as a result of problems with their own product.

Nuclear energy originated in the nuclear weapons programs of World War II. Following the war, control of nuclear research passed from military to civilian control with the creation of the Atomic Energy Commission. Early plans to use nuclear weapons for mega- projects (e.g., excavating a harbor on the coast of Alaska) were dismissed amid concern over potential radioactive . The first commercial nuclear power plants generated electricity in the late 1950s. Nuclear power generation increased steadily until the 1970s and appeared to be on the road to acceptance as fuel costs increased during the 1973 oil crisis. However, the honeymoon

Figure 13. Three Mile Island Unit 1 reactor, Pennsylvania, with Susquehanna River in background. The Unit 2 reactor is nearby but is no longer in use. Image courtesy of the Nuclear Regulatory Commission (NRC).

14 ended amidst with construction costs and a widely reported accident at the Three Mile Island Unit 2 reactor (1979), near Harrisburg, Pennsylvania (Fig. 13). Furthermore, the demand for energy decreased as and efficiency gained popularity.

A dangerous nuclear accident at Chernobyl in the former (now the Ukraine) in 1986 lessened the chances for a rebound in nuclear fortunes. The accident resulted from an unauthorized experiment by operators who were testing the capabilities of the reactor. Two explosions blew the top of the power plant. The reactor did not have a containment vessel (unlike U.S. reactors) allowing the escape of radioactive into the atmosphere. The accident was revealed when Sweden detected an increase in wind-borne radiation. As a result of the accident, over 200,000 people had to be moved from the area surrounding the damaged reactor; 31 workers and emergency personnel died immediately after accident and an unknown number of people died later because of exposure to lesser levels of radioactivity. A concrete "sarcophagus" was built over the damaged reactor in an unsuccessful effort to contain any further leaks.

The nuclear industry argues that improved reactor design and the absence of airborne pollutants associated with fossil fuels make nuclear power an ideal source for future energy.

The Nuclear Fuel Cycle The nuclear fuel cycle represents the series of steps that begin with the mining of uranium, continue through the generation of electricity, and end with the disposal of nuclear waste.

Uranium Mining and Milling: Uranium is approximately 500 times more abundant in Earth’s crust than gold. The top-five sources of uranium are Canada (12,029 tonnes, 34% of world production), , Niger, Namibia, and U.S. (Fig. 14). Over half of uranium is produced from open-pit mines. The original uranium ore contains 0.1 to 1% uranium. Uranium is removed from ore by milling to produce a refined ore that contains approximately 60% uranium. During the milling process the uranium is dissolved from the ore and reprecipitated in a concentrated form known as “yellowcake.”

Uranium Enrichment: Additional processing is required before the uranium is in a form that can be used in a reactor.

15 Figure 14. U.S. Natural uranium consists of two isotopes of uranium. The bulk and 238 of natural uranium is U . Only 0.7% of natural uranium is the production plants. isotope U235 that is capable of undergoing fission, the process Image courtesy of by which energy is produced in a nuclear reactor. Enrichment Energy Information increases the concentration of U235 to approximately 4% of Administration. the uranium mixture by removing much of the U238 isotope. The uranium is formed into pellets that are placed in metal tubes to form the fuel rods in a reactor fuel assembly.

Nuclear Power Generation: Nuclear reactors generate electricity from heat much the same way coal- or oil-fired power plants do. The heat converts water to steam, steam spins a turbine, and the spinning turbine generates electricity. The big difference is in how the heat is generated. In power plants using fossil fuels the fuel of choice is simply burned. In a nuclear plant, nuclear fission, the splitting of the nucleus of an atom, is the heat source. Neutrons ejected from the split atom hit adjacent atoms, causing them to fission. Uranium undergoes nuclear fission in the fuel rods of a nuclear reactor. Neutron- absorbing control rods may be inserted in the reactor to slow down the rate of the reaction and produce less heat. Both fuel rods and control rods are stored in water that serves to cool the rods and moderate the nuclear fission reactions. The radioactive material in fuel rods is not sufficiently enriched to cause a nuclear explosion but a runaway reaction could result

16 Figure 15. Map of the distribution of U.S. nuclear reactors. Image courtesy of the Nuclear Regulatory Commission (NRC).

in overheating of the surrounding water and cause a steam explosion.

Nuclear Reactors: A typical nuclear power plant in the U.S. is granted a 40-year license for operation but many are taken out of service (decommissioned) before the end of that time interval. The oldest currently operating nuclear reactors in the U.S. started up in 1969. There are over 100 nuclear power plants operating in the U.S. (Fig. 15; 104 as of November, 1999) but no new plants have been ordered in the last 20 years. Consequently, as the current plants are decommissioned the total number of operating nuclear plants will inevitably decline.

Figure 16. Graph of proportion of electricity from nuclear power for France (58 reactors), Belgium (7), Sweden (12), Japan (52), and U.S. (104). There are 428 nuclear power Some nations rely heavily on nuclear power to supply the bulk plants worldwide of their electricity (Fig. 16). France generates over three- (1999). quarters of its electricity from 58 nuclear power plants and Lithuania generates 77% of its electricity from just two plants. In contrast, the U.S. has 104 nuclear reactors that produce much more electricity than France (96,977 megawatts vs. 61,723 megawatts). However, this represents a smaller

17 proportion (19%) of national electricity production than several other nations. Europe is home to more nuclear reactors than any other continent (173), and Africa and South America have only 5 between them.

Nuclear Energy and the Future There has recently been renewed interest in the use of nuclear power in some quarters (mainly from advocates in the nuclear industry). They cite three principal benefits of the use of nuclear energy: 1. Air pollution and global warming, associated with fossil fuels, are not produced by nuclear power plants. 2. Electricity from nuclear power would reduce the nation's dependence on foreign oil which is growing increasingly scarce. 3. New reactors have safer standardized reactor designs that markedly reduce the potential for an accident.

However, for nuclear power to become a viable energy alternative in the immediate future it must first deal with the following issues: 1. Many existing nuclear power plants are entering old age and will have to be decommissioned, reducing the energy- production capacity in the U.S. 2. More nuclear power plants mean more high-level nuclear waste. The nation still has no repository for this waste and will not have a disposal site until at least 2010.

Nuclear Waste Nuclear waste comes in a variety of forms, each with different storage requirements but it is the disposal of high-level nuclear waste that presents the greatest challenge for the future. Although high-level (e.g. used fuel rods) composes a relatively small volume of all nuclear waste it represents nearly all (95%) of the radioactivity nuclear and may remain dangerous for over 10,000 years. Like several other nations that rely on nuclear energy, the U.S. is attempting to find a suitable site where it can store nuclear waste safely for thousands of years. The potential site is located below Yucca Mountain, Nevada (Fig. 17), about a one hour drive north of Las Vegas.

18 The Department of Energy (DOE) initially identified nine potential nuclear dump sites but later shortened the list to three (Fig. 17; Hanford, Washington; Deaf Smith County, Texas; Yucca Mountain, Nevada). The DOE hoped to investigate the geology of each site thoroughly to determine which would be the safest repository for the dangerous waste. However, in December 1987, Congress saw a chance to save some money and directed DOE to study just the Yucca Mountain site. Nevada, which has no nuclear power plants, has fought vainly against hosting the site.

Figure 17. Three proposed sites for a possible high-level nuclear waste disposal facility were considered (map right) before Congress chose to locate the site below Yucca Mountain, Nevada (left). Image courtesy of the Yucca Mountain Project.

Not only must a high-level nuclear waste disposal facility be safe from accidental entry and sabotage, potentially for a few hundred thousand years, it must also be safe from geologic hazards that may release the radioactive materials. The ideal site would be geologically stable to ensure that groundwater could not infiltrate through the waste, and neither earthquakes nor volcanic eruptions would rupture the containment structure.

Geologic Setting of Yucca Mountain The waste would be stored in sealed containers in an underground vault approximately 300 m (1,000 feet) below the surface (Fig. 18). The site at Yucca Mountain is favorable for waste disposal because: • It is located in the desert of southern Nevada far from population centers (Las Vegas is ~100 km south).

19 • The vault would be hollowed out of a layer of volcanic tuff, a resistant igneous rock with very low porosity (spaces within the rock that may contain water) and low permeability (the ability of water to flow through the rock). • In addition, the site gets ~15 cm (6 inches) of precipitation a year, most of which evaporates in the desert heat. Project scientists believe that it is unlikely that water could inundate the disposal facility and radioactive materials into the surrounding environment. • Furthermore, the local groundwater source is 240 meters (~750 feet) below the site, making it difficult for any leaks to pass quickly (before detection) to the groundwater supply.

Figure 18. Approximate position of the nuclear waste repository in impermeable volcanic tuff rocks below Yucca Mountain, Nevada.

However, some scientists point out that certain geologic features point toward potential problems in the future: • Groundwater flow may be accelerated along fractures and faults that exist in the region, and that evidence points to an elevated water table (groundwater) in the relatively recent geologic past (~10,000 years ago). • Nevada is one of the most seismically active states after Alaska and California. Some have suggested that the threat of a damaging earthquake is too great to take the risk of building the disposal facility in Nevada. However, although there have been numerous small earthquakes near the site, few have been of sufficient magnitude to pose any threat and a structure could be engineered to withstand the moderate-size earthquakes that occasionally occur in southern Nevada. • Geologically recent (<10,000 years) volcanic activity has also occurred nearby but scientists at Yucca Mountain have estimated that there is little probability that future activity will impact the disposal facility.

20 The original opening date for the high-level nuclear waste repository was 1998 but was subsequently changed to 2003 and then to 2010, reflecting the controversy the site has generated in Nevada and nationwide. The development of such a site is essential for the permanent disposal of the nuclear waste that has already been generated by nuclear power plants. Without a working disposal facility, the long-term viability of nuclear power in the U.S. is in jeopardy.

Think about it . . . Create a concept map that illustrates the issues surrounding the use of nuclear energy.

Alternative Energy Resources

• Renewable energy is environmentally friendly but its future potential is dependent upon the rate of technological development and operating costs. • The potential for the use of renewable energy varies with location as , climate, and geology. • Biomass, hydropower, and geothermal energy have drawbacks that make it unlikely that they will increase their share of U.S. energy significantly in the future. • Passive solar energy requires that structures be oriented to receive light and heat from sunlight and active solar energy converts solar radiation to electricity. • Wind energy accounts for 0.5% of all U.S. energy but could generate up to 20%.

Future energy must come from one of the three principal energy sources currently in use. Approximately 80% of the nation's current energy needs are supplied by fossil fuels (oil, gas, coal) that carry with them the threat of potential energy shortages as well as associated environmental degradation from air pollution and concerns about global warming. Nuclear power supplies less than 10% of total U.S. energy and is

21 unlikely to undergo a resurgence any time soon in the face of public skepticism over the possibility of a nuclear future. Renewable energy (hydropower, wind, solar, biomass, geothermal), therefore, remains the sole potential energy source that will ensure minimal environmental harm and also has the potential to free us from reliance on foreign suppliers. Technological improvements and economies of scale may reduce costs sufficiently to increase the proportion of U.S. energy from renewable sources from its current level (Fig. 19; less than 10%) to at least 30% of total energy use.

Figure 19. Proportion of U.S. energy generated by renewable energy vs. fossil fuels and nuclear power.

Controls on Renewable Energy Unlike fossil fuels, renewable energy must often be used relatively close to where it is generated. Transmission lines may conduct electricity up to hundreds of kilometers from its original source but are not efficient enough to transmit it cross- country to any location where it is needed. Hydroelectric and geothermal power are more common in western states because of the underlying geology. Stream gradients are relatively steep and thousands of acres of undeveloped lands were available to be flooded behind massive dams. In addition, recent volcanism is feed by shallow magma chambers that provide a ready heat source for circulating groundwater. Climate conditions also favor greater development of solar and wind power west of the

Figure 20. The most widely used renewable energy sources are biomass (e.g., burning wood) and hydroelectric power.

Mississippi River in regions characterized by high insolation

22 (incoming solar radiation) and/or high consistent wind speeds. Biomass (wood products) represents the only form of renewable energy that can be readily transported in its primary state. The burning of wood (biomass) and hydropower represent the great majority of current renewable energy use in the U.S. (Fig. 20).

Figure 21. Area of land necessary to generate 1 billion kilowatts of electricity per year for different energy sources. Renewable sources require more land per measure of electricity. Two of the principal restrictions in the development of alternative energy sources are the demand for land and the relative cost (Figs. 21, 22). Fossil fuels require a relatively small land area to be produced and refined. In contrast, hydroelectric power requires the flooding of large areas to ensure a sufficient supply of water. Biomass (burning of organic material such as fast-growing varieties of wood like willow) demands the greatest land area to generate a given amount of electricity (Fig. 21). It is unlikely that sufficient land area can be converted to forests to produce the wood necessary to replace fossil fuels in power plants. Most land is already dedicated to other uses (agriculture, buildings) or does not have the climate required to develop forests.

Figure 22. Relative cost to generate one kilowatt-hour of electricity. Current costs of solar energy are approximately 4 times those of electricity generated at a coal-fired power The main constraint on use of renewable energy sources today plant. is cost (Fig. 22). As long as renewable energy is more expensive than conventional fuels it will not be widely used. Some forms of renewable energy (wind, hydroelectric) are competitive with the cost of building nuclear power plants but only hydroelectric power compares favorably with the main source of electricity in the U.S., coal.

23 Hydropower production in the U.S. is a close second to the world's leader (Canada). Energy is generated when water dropping from higher to lower elevations is used to drive turbines that rotate generators to produce electricity. Early settlers used water wheels alongside rapidly flowing streams. Today, power is generated by the 200-meter (660 foot) drop of water within giant dams on western rivers such as the Colorado (Fig. 23) and Columbia.

Although construction of the earliest western dams was viewed as a blessing in the parched drylands of Arizona and California, later projects met with increasing opposition because of the dramatic changes in the physical environment both upstream (drowned lands, siltation of reservoirs) and downstream (altered stream channels, uniform [unnatural] streamflow). Many of the best potential dam sites are now in national parklands or have for from farming and recreation interests. It is therefore considered unlikely that any new large dams will be built in the U.S. but mini-hydro projects that serve a relatively small population with minimal environmental disruption may become increasingly popular.

Figure 23. Left: Hoover Dam on the Colorado River with Lake Mead in the background. Right: The Geysers, a geothermal system near Calistoga, California. Image by David Parsons. Image courtesy of Dept. of Energy National Renewable Energy Laboratory.

Geothermal power in its most dramatic form uses heat from sources of underground steam or hot water (hydrothermal resources) to generate steam used to drive turbines and thus generate electricity (Figs. 23, 24). Used waters are recycled back underground to recharge the geothermal reservoir and continue the process. Groundwater is heated when it percolates to sufficient depths to be warmed by Earth's geothermal gradient (~25oC/km) or comes in contact with hot rocks near a magma chamber. Geothermal power plants are found in several

24 Figure 24. Geothermal energy systems exploit hydrothermal resources. Heat is extracted from hot groundwater and the cool wastewaters are returned to the hydrothermal system.

western states (e.g., California, Nevada, Utah, and Hawaii) and produce electricity at rates of 5 to 8 cents per kilowatt-hour. Although it has potential for growth, geothermal power is unlikely to take a large share of the U.S. energy market because it is restricted by location to sites in sparsely populated areas of the West.

Solar and wind energy represent the greatest potential for technological advances and increasing energy production among renewable energy sources.

Solar Energy Solar energy accounts for approximately 1% of all U.S. energy use. Passive solar energy refers to using the heat from sunlight to warm buildings (Fig. 25) and was first used in Greek homes over 1,500 years ago. It is estimated that sunlight could be used to supply up to 90% of home heat, depending upon location.

Figure 25. Modern house with passive solar design, near Denver, Colorado. House combines passive (south-facing windows) and active solar technologies. Image by Dave Parsons. Image courtesy of Department of Energy National Renewable Energy Laboratory.

25 Passive solar energy has greater potential in the sunny desert Southwest than the overcast Pacific Northwest. The use of passive solar energy can be readily incorporated into the construction of new homes that can be built with windows facing south to receive maximum insolation. Unfortunately, such techniques are less useful in older homes.

Active (direct) solar energy can be used in two forms. Water or oil may be heated in solar collectors that use mirrors to focus the sunlight onto the liquid (Fig. 26). The hot liquid is then used for heating. In contrast, photovoltaic cells convert sunlight directly to electricity (Fig. 27).

Figure 26. Solar One, California; the tower in center of image is a 10-megawatt solar receiver. Image by Sandia National Laboratories, courtesy of Department of Energy National Renewable Energy Laboratory (DOE/NREL). Solar energy still has some hurdles to overcome before it can be used extensively. At present some solar energy systems are too inefficient for widespread use. For example, when coal is burned approximately half the heat generated can be converted to electricity. Current models of photovoltaic cells convert less than 10% of sunlight into electricity. Some developing nations are at the forefront of solar energy because it may be more economical to use photovoltaic cells to generate electricity in remote locations instead of having to build transmission lines Figure 27. Left: Woman in uses a photovoltaic- powered pump to collect water. Image by Harin Ullal. Right: Homes in a rural Brazilian village use photovoltaic cells to provide light. Image by Roger Taylor. Images courtesy of Department of Energy National Renewable Energy Laboratory.

26 to conduct electricity large distances to serve relatively small populations (Fig. 27).

Wind Power Wind power accounts for approximately 0.5% of U.S. electricity (Fig. 28). Technological advances are making wind power increasingly competitive with costs ranging from 1 to 10 times those of fossil fuels. Suitable wind velocities (over 20 km/hr) are consistently present over about 13% of the U.S. and estimates suggest wind power could generate as much as 20% of U.S. energy in the future.

Figure 28. A series of 100 kW wind turbines near Altamont Pass, California. Image by Ed Linton. Image courtesy of Department of Energy National Renewable Energy Laboratory (DOE/NREL). The areas with the greatest potential for wind power are determined by the patterns of prevailing winds that consistently exhibit sufficient velocity and reliability only over the Great Plains states. Unfortunately, these states are hundreds of miles from population centers were the power would be needed. New or improved transmission lines necessary to get the power to suitable markets are unlikely to be built until it can be demonstrated that the region can generate sufficient energy. However, there is little incentive to invest in huge wind farms without such a delivery system in place. The great majority of U.S. wind turbines are located in California (Fig. 28).

Think about it . . . 1. Use the Venn diagram found at the end of the chapter to compare and contrast the characteristics of nuclear energy and renewable energy resources. 2. The graph located at chapter end compares projected plots of the generation of wind energy vs. time (1985- 2025) with nuclear energy capacity vs. time (1960- 2000). Make some predictions on the future of wind energy using the evolution of nuclear power as a model.

27 Air Pollution

• Toxic air pollution killed thousands in the relatively recent past. • Industrial emissions are recorded annually by the EPA's Toxic Release Inventory. • The concentrations and emissions of six criteria pollutants are regularly measured against a set of national standards. • National air quality is improving despite increases in population, transportation, and economic growth. • In addition to various health effects, air pollution also causes acid rain and can reduce visibility.

Air quality diminished in big following the and declined further as the popularity of the automobile increased during the last century. Air pollution at Earth's surface is at least partially dependent upon weather conditions. The combination of tall smokestacks and steady prevailing winds will generally ensure that emissions are dispersed and diluted.

Figure 29. Normal atmospheric conditions (left) and conditions responsible for a temperature inversion (right). A temperature inversion occurs when warm air lies above cold air, preventing the Air temperature decreases upward under normal atmospheric dispersion of conditions and emissions rise upward. However, atmospheric pollutants. conditions may sometimes be reversed creating a situation where cold air is trapped below warm air, creating a temperature inversion (Fig. 29). Under such conditions the cold air will remain stagnant, unable to rise, until dispersed by changing weather conditions. Dense concentrations of pollutants trapped close to the ground surface may create lethal air pollution similar to that which caused 5,000 deaths in a single weekend in London, 1952. Twenty people died and hundreds became ill as a result of toxic air pollution in Donora, Pennsylvania, in October 1948. Emissions from a wire plant were trapped close to ground level by a temperature inversion. Most of those affected were elderly.

28 Criteria Pollutants National Ambient Air Quality Standards have been determined for only seven pollutants; , sulfur dioxide, , nitrogen oxides, lead, hydrocarbons, and photochemical oxidants (). The EPA recognizes six common "criteria" pollutants:

Criteria Pollutants Source Carbon monoxide Auto emissions Nitrogen dioxide Auto emissions, electric utilities Sulfur dioxide Electric utilities, industry Particulates Various (e.g., electric utilities, wood stoves) Ozone NOx + volatile organic compounds + sunlight Lead Leaded gasoline, lead smelters

Concentrations of criteria pollutants measured in comparison to National Ambient Air Quality Standards (NAAQS). The six criteria pollutants have decreased in concentration nationwide over the last few decades (Fig. 30), and the volume of

Figure 30. Trends in emissions of sulfur dioxide (blue), nitrogen oxides (green), and volatile organic compounds (red) from 1900 to 1997. Original graph from U.S. EPA National Air Quality and Emissions Trends Report, 1997.

emissions of these pollutants has also declined. However, one related group of pollutants, nitrogen oxides, has shown a slight increase in emissions over the last decade. Recent air regulations are aimed at reducing this last holdout.

Concentrations are linked to the direct emissions of pollutants or associated gases (e.g., volatile organic compounds, nitrogen oxides). The bulk of U.S. air pollution comes from the combustion of fossil fuels and (Fig. 31). These activities are concentrated in urban areas where millions of people live in close proximity and devour prodigious amounts of energy. Most emissions have decreased despite

29 economic growth and increases in population and transportation but some locations still are above NAAQS for individual pollutants or groups of pollutants. The U.S. EPA estimates that ~80 million people live in counties that exceed one or more air quality standards.

Figure 31. States containing top-10 sources of each of the criteria pollutants with a listing of the types of sources that generate each type of . Information from U.S. EPA's Airsdata website.

National efforts to reduce air pollution initially centered on improving automobile fuel efficiency standards (greater distance on fewer gallons of gas) or modifying gasoline composition (unleaded gas). Mass transit systems have been added in densely populated cities in an effort to get people out of their cars and into buses or trains. These steps were able to reduce emissions of almost all major pollutants but improvements have recently slowed as more fuel-efficient cars have been overtaken in popularity by minivans and sports vehicles that have lower fuel-efficiency standards (27.5 vs. 20.5 miles per gallon).

Criteria Pollutant Health Effects Carbon monoxide Reduces availability Nitrogen dioxide Respiratory illnesses sulfur dioxide Respiratory illnesses, Particulates Respiratory illnesses Ozone Respiratory illnesses Lead Anemia, kidney disease, neurological problems

30 Although some extreme air pollution events, like those in London in 1952, can be directly linked to severe illness or death, the health effects associated with less-profound pollution events are more ambiguous. Health researchers point to a 56% increase in asthma cases for U.S. residents aged under 18 from 1982 to 1991 and suggest there is a correlation between pollution levels and illness and mortality rates.

Figure 32. Good (left) In addition to health effects, air pollution can also result in acid and poor (right) rain and decreased visibility. Acid rain is precipitated visibility at the Grand Canyon, Arizona, as downwind from areas with sulfur dioxide and nitrogen oxide a result of air emissions. Acid rains leach nutrients from , damage pollution. From an forests, and may cause the acidification of lakes. Recent data original series of 15 have highlighted decreasing sulfate levels (less acid rain) slides at the Grand because of decreasing emissions of contributing pollutants. Air Canyon Visibility pollutants absorb and scatter light to create a that limits Transport Commission. visibility (Fig. 32).

Summary

1. What is the source for the majority of energy used in the U.S.? Fossil fuels account for the bulk of U.S. energy use. Coal, natural gas, and petroleum are burned to generate electricity and refined petroleum products (e.g., gasoline) are used in transportation. Nuclear energy and alternative (renewable) energy sources (hydroelectric power, biomass) account for the

31 remainder of electricity generation and approximately 10% of all U.S. energy consumption.

2. What factors influence energy use in different locations? States with large populations, large land area (greater distances to travel), and energy-intensive industries (e.g. oil refining, chemicals), typically use the most energy. Texas is the most energy-hungry state because it combines all three of the above components. States such as Wyoming and Alaska rate highly in energy use per person because gas consumption is high in these large, sparsely populated states. The U.S. uses more energy than any other nation because it also combines a large population (third in the world) with a large land area, and an extensive industrial base.

3. How do fossil fuels form? Fossil fuels form from decayed organic material. Oil, coal and natural gas are the most common products of this process. Oil and gas form from organic material in microscopic marine organisms, whereas coal forms from the solid resins and waxes that characterize land plants. Tar sands and oil shale are less common and are less widely used because extraction of oil from these deposits is more expensive than producing the other forms of fossil fuels.

4. How are oil and gas deposits formed? The two principal requirements in the generation of oil and gas are time and a specific range of temperature. The first requirement is an organic-rich source of sediments that are converted to sedimentary rock. Next, chemical reactions occur during burial under conditions of increasing temperature and pressure. The reactions occur at temperatures of 50 to 100oC. The reactions change the organic molecules to hydrocarbon molecules. With increasing time the hydrocarbons become more mature changing from heavy oils to lighter oils and finally, to natural gas. Fossil fuels are considered non- renewable resources because it is not possible to replenish consumed reserves at geological rates of formation. Commercial hydrocarbon deposits are not found in relatively old (Precambrian) rocks because these rocks have been around for too long and organic remains would long ago have been converted to gas and have escaped from the rocks. Likewise, deeply buried rocks have typically undergone temperatures that are too high to allow hydrocarbons to remain.

5. Where are the world's oil and gas deposits located?

32 Global oil reserves are made up of over 1,000 billion barrels of oil, approximately two-thirds of which is present in countries of the Middle East (e.g., Saudi Arabia, Iran, Iraq, Kuwait). Major gas deposits are found in the same nations as well as Russia. Nations with the largest oil reserves typically use relatively little oil; in contrast, countries that use a lot of oil (e.g., U.S., Japan, Germany) may have relatively small oil reserves.

6. How is coal formed? The two principal requirements in the generation of coal are time and a carbon-rich organic source made up of the solid resins and waxes of plants. With increasing burial, water is expelled from the organic material and carbon content increases.

7. What is coal rank and how does it vary? Coal rank is a measure of the carbon content. Rank increases from a minimum of 30% carbon content for peat to a maximum of 99% or more for anthracite. Burned coal releases more heat with increasing rank and less ash remains following combustion. In order of increasing rank, coal type varies as follows; peat, lignite, sub-bituminous coal, bituminous coal, and anthracite. Sub-bituminous and bituminous coals are the most common coal types.

8. What other properties of coal are important? The sulfur content of coal is a key factor in determining what type of coal is used to generate electricity. High-sulfur bituminous coals contribute to air pollution but yield more heat per ton of coal than low sulfur sub-bituminous coal. Utility companies must balance the cost of guarding against pollution with the extra cost of transporting more low-grade coals that generate more waste (ash) following combustion. Air pollution represents an external cost associated with the combustion of fossil fuels. The use of coal would become less economically attractive if these costs were applied to the original (internal) cost of coal. Scientists predict that fossil fuel emissions will lead to a warmer "greenhouse" world, initiating a potential cascade of negative economic repercussions. Consequently, future energy policy may not be concerned with how much fuel is left, but may instead focus on how to use it without prompting changes in global climate.

9. How are coal resources distributed?

33 The world's coal resources are distributed more evenly than oil and gas resources and favor some of the largest nations. The U.S. and contain approximately half of the world's coal. Within the U.S., there are two regions that contain most of the nation's coal. Appalachian basin states (e.g., Ohio, Kentucky, Pennsylvania, West Virginia) produce high-rank bituminous coals and anthracite. These coals are typically produced from underground mines. Great Plains states (Montana, Wyoming, North Dakota, South Dakota, Colorado) produce sub- bituminous coals from relatively inexpensive surface mines.

10. How has technology changed the generation of energy? Fossil fuel use dominated the first half of the century in all sectors of energy consumption. Nuclear power held much promise for electricity generation at the mid-century but nuclear accidents have continued to raise public concerns about the safety of nuclear plants. New technologies associated with solar and wind energy hold hope for the future as they have few of the drawbacks associated with other energy sources (pollution, safety). However, renewable energy sources will be limited by climate and have little potential for replacing petroleum as the energy source of choice for transportation.

11. How is nuclear energy generated? Uranium ore contains is a small fraction of the uranium isotope (U235). The radioactive isotope becomes more concentrated following milling and enrichment. The uranium isotopes split, releasing neutrons, when placed in fuel rods in a reactor assembly and the neutrons are absorbed by other U235 isotopes, causing further fission. Splitting of the isotopes also generates heat that converts water to steam and drives a turbine to generate electricity.

12. Which nations rely most heavily on nuclear energy? Thirty-three nations generate electricity using nuclear power. The U.S. uses more electricity from nuclear reactors than anyone else (28% of global electricity generated by nuclear power) but this represents a relatively small proportion of the nation's total electricity use (19%). Some small countries generate the bulk of their electricity with a few nuclear plants (Lithuania, 2 nuclear reactors, 77% of electricity; Belgium 7 and 55%; Switzerland 5 and 41%). Some of the world's most heavily populated nations have either no operating nuclear power plants (e.g., Indonesia) or very few relative to the size of their populations (China has 3; India, 10; Brazil, 1).

34 13. What are the advantages to using nuclear power to generate electricity? Nuclear advocates typically identify three principal benefits of the use of nuclear energy: (1) a reduction in air pollution and decrease in the potential for global warming associated with fossil fuel use, (2) electricity from nuclear power would reduce the nation's dependence on foreign oil, (3) new reactors have safer standardized reactor designs that markedly reduce the potential for an accident.

14. Sounds pretty convincing, why don't utility companies build more nuclear reactors? Assuming that people could be convinced of the safety of nuclear reactors - a big “if” at present, there are still two issues that must be dealt with before nuclear energy becomes viable in the long term. First, many existing nuclear power plants are approaching the time when they have to be retired from use (decommissioned) and it will undoubtedly cost companies a lot of money to dismantle these plants in the relatively near future leaving fewer funds for building new reactors. Second, more nuclear power plants mean more high-level nuclear waste and there is still nowhere to permanently (100,000's years) store the waste until it is no longer harmful. And just wait until they start trucking waste cross-country to Yucca Mountain.

15. Why are they trying to dump nuclear waste under a mountain in Nevada? Locating a dump for highly radioactive waste requires a balance be struck between suitable geologic conditions and cultural and political forces. Nevada's geology and climate makes it a suitable site for a repository and its relatively small population makes it politically feasible to site the dump in the state. Any suitable site must have low-porosity/permeability rocks that will protect the waste from groundwater infiltration and must be remote enough so that people are unlikely to accidentally expose the material during future development. Ideally, the site would also be far from potential hazards that might damage the integrity of the repository. Nevada is less than ideal on this score because it has frequent earthquakes (small-moderate) and relatively recent volcanic activity. However, few places are without some form of risk and scientists will analyze the site to determine if the potential hazards make it an unsound choice.

16. What is renewable energy?

35 Renewable energy comes in a variety of forms that remain undiminished with use. It also has the potential to have less of a negative impact on the environment than fossil fuels or nuclear power. The principal types of renewable energy include geothermal, hydroelectric, biomass, solar, and wind.

17. What forms of renewable energy are currently significant contributors to U.S. energy? Biomass (burning of wood) and hydroelectric power (electricity generated from dams) account for most of the renewable energy generated in the U.S. today but neither has much potential for growth because there are few rivers left to dam and limited area to convert to tree plantations to generate biomass.

18. What forms of renewable energy hold the greatest promise for the future? Solar and wind power. Wind power generation is increasing rapidly worldwide (~20% annually) and photovoltaic cells are cost-effective in locations that are too distant to be supplied by a traditional power grid. Solar power will grow more rapidly as advancing technology reduces the cost of new photovoltaic cells.

19. What is a temperature inversion? A temperature inversion occurs when cold air lies below warm air. Under normal conditions, the temperature of air decreases with increasing altitude. A parcel of warm air will rise through the overlying colder air, diluting pollution as it is carried higher in the atmosphere. Pollutants become concentrated below a blanket of warm air when cold air lies immediately above the ground surface. The cold air remains trapped near the surface until changing weather conditions restore normal conditions.

20. What are criteria pollutants? These are the six regulated pollutants that are generally products of the combustion of fossil fuels. The concentration of particulates, sulfur dioxide, carbon monoxide, nitrogen dioxide, lead, and ozone are compared to national standards. Locations that have elevated concentrations must take steps to reduce them to within the range of the standards.

21. Where does most air pollution come from? The primary source of air pollution is from the combustion of fossil fuels. Almost half the energy consumed in the U.S. is from petroleum and over half the electricity used comes from

36 burning coal. These activities are concentrated in urban areas where millions of people live in close proximity and devour prodigious amounts of energy.

37 Energy Consumption vs. GDP

GDP is a measure of the total production and consumption of goods and services, think of it as the wealth of the nation. Energy consumption is the amount of energy used for transportation, industry, domestic use, commerce, etc. Note that both measures used in this exercise are per capita (per person).

1. Examine the partially completed graph of gross domestic product (GDP) per capita vs. energy consumption per capita below. Label the points that represent where you think the following nations would plot on the graph. Note: China, India, Indonesia, and Brazil are ranked 1, 2, 4, and 5 in the world in total population (the U.S. is third).

China Indonesia Japan Saudi Arabia India Brazil Australia Nigeria

2. Can you suggest explanations for the distribution of the nations on the graph?

38 Venn Diagram: Oil vs. Coal Resources

Use the Venn diagram, below, to compare and contrast the similarities and differences between the characteristics of oil and coal resources. Print this page and write features unique to either group in the larger areas of the left and right circles; note features that they share in the overlap area in the center of the image.

Oil Coal

39 Sulfur Content vs. Heat Content of U.S. Coal

Examine the map of U.S. coal resources below and predict where the five numbered points on the graph of sulfur content vs. BTU might plot on the map.

40 Venn Diagram: Nuclear Energy vs. Renewable Energy

Use the Venn diagram, below, to compare and contrast the similarities and differences between the characteristics of nuclear energy and renewable energy resources. Print this page and write features unique to either group in the larger areas of the left and right circles; note features that they share in the overlap area in the center of the image.

Nuclear Energy Renewable Energy

41 The Future of Wind Energy

Read the statements below and examine the graph before answering the questions that follow.

Wind energy has grown more rapidly than any other energy source in recent years. Approximately 9.6 gigawatts of energy were generated by wind power in 1998, up from 1 gigawatt in 1985. From 1990 to1998, the global annual rate of growth for the following energy sources was: wind power 22.2%, oil 1.8%, nuclear power 0.6%, coal 0.0%.

Nuclear power generated approximately 1 gigawatt of energy in 1960. The use of nuclear energy expanded rapidly in the 1970s before becoming less appealing as a result of some well- publicized nuclear accidents between 1979 and 1986. Nuclear energy generation has leveled off at about 340 gigawatts/year in recent years.

The graph below compares projected plots of the generation of wind energy vs. time (1985-2025) with nuclear energy capacity vs. time (1960-2000). The graph projects current trends in the growth of wind energy into the future at 10%, 15%, and 20% growth rates.

42 1. If we assume a comparable growth rate, approximately how long will we have to wait until wind energy can produce the same amount of energy as is currently generated by nuclear power? a) 3-6 years c) 21-24 years b) 10-12 years d) 35-40 years

2. What factors might cause wind energy generating capacity to level off (wind power growth rate would fall to near zero) in the future.

3. Will wind energy be as productive as nuclear power? Explain your answer.

43