Chapter 11 Fossil Fuels Lecture Outline:

Transcription

1 Fossil Fuels Lecture Outline: I. Energy Sources and Consumption A. Just a few hundred years ago, almost all energy used by people was derived from local energy sources (agriculture, wind and water) i. People relied on their own physical energy and the energy of animals to do work ii. These energy sources were limited by energy density, the amount of energy contained within an energy source B. Today, 60% of the commercial energy consumed worldwide is used by high developed countries (HDCs) i. People in HDCs rely on energy consuming machines to do work ii. The larger energy input is one reason the agriculture productivity of HDCs is greater than that of developing countries iii. Additional energy demands may be met by increased energy efficiency C. An increase in economic development is usually accompanied by a rise in per capita energy consumption D. In the U.S., industry (production of materials) accounts for 42% of energy consumption, 33% is used to make buildings and/or homes comfortable, and 25% is used primarily in transportation E. Energy for China i. In 2004, China became the world s second largest importer of oil 1. China currently dominates international concerns over global climate warming 2. In 2009, China will likely pass the U.S. as the top CO2 emitter II. Fossil Fuels A. Energy is obtained from a variety of sources, including fossil fuels (coal, oil, and natural gas), nuclear reactors, biomass, solar and other alternative energy sources (water, wind, etc.) i. Fossil fuels supply most of the energy required in North America ii. They are nonrenewable resources; formation does not keep pace with current use B. How fossil fuels are formed i. Coal was formed from the remains of ancient plants that lived millions of years ago ii. Oil was formed from the remains of ancient microscopic aquatic organisms iii. Natural gas is composed primarily of methane and was created in much the same way as oil, except at higher temperatures III. Coal A. In the 18 th century, coal replaced wood as the dominant fuel in the Western world i. Coal powered the steam engine and supplied the energy for the Industrial Revolution

2 ii. Today it is used to produce electricity and steel iii. Coal consumption has surged in recent years in China and India B. Lignite, subbituminous coal, bituminous coal, and anthracite are the four most common grades of coal i. Lignite is a soft, moist coal that produces little heat and is often used to power electric power plants ii. Subbituminous coal has a relatively low heat value and sulfur content, and is also used in coal-fired electrical power plants iii. Bituminous (soft) coal produces substantially more heat that the lignite or subbituminous, but also contains a higher sulfur content; it is used extensively in electric power plants iv. Anthracite (hard) coal is the highest grade of coal and produces the fewest pollutants per unit of heat released (due to low sulfur content); it has the highest heat-producing capacity of any grade of coal C. Coal reserves i. Coal is the most abundant fossil fuel in the world, and is found primarily in the Northern Hemisphere ii. World coal reserves could last more than 200 years at the present rate of consumption D. Coal mining i. Surface mining extracts the mineral and energy resources near Earth s surface by first removing soil, subsoil, and overlying rock strata 1. It is used to obtain 60% of the coal mined in the U.S 2. It is often cheaper, safer, and generally allows more complete removal of coal from the ground 3. It does, however, have the potential to cause more serious environmental problems ii. Subsurface mining extracts the mineral and energy resources from deep underground deposits E. Safety problems associated with coal i. During the 20 th century, more than 90,000 American coal miners died in mining accidents ii. Miners have increased risk of cancer and black lung disease F. Environmental impacts of the mining process i. Prior to 1977 (SMCRA the Surface Mining Control and Reclamation Act), abandoned surface coal mines were usually left as large open pits or trenches and streams were polluted with sediment and acid mine drainage ii. The SMCRA requires coal companies to restore areas that have been surface mined, requires permits and inspections of active coal mine operations, and prohibits coal mining in sensitive areas iii. Mountaintop removal is one of the most land-destructive types of surface mining; it uses a dragline to remove the mountain top to reach the coal below G. Environmental impacts of burning coal i. The Earth s CO2 equilibrium has been disrupted by the enormous amounts of CO2 produced through fossil fuel consumption this past century 175

3 ii. This, in turn, has lead to a rise in global temperature and various environmental issues associated with higher temperatures 1. Melting of polar ice caps 2. Rising sea levels 3. Future flooding of coastal areas, increasing coastal erosion and associated violent storms iii. Coal burning generally contributes more air pollutants (including CO2) than does burning either oil or natural gas (i.e., mercury, sulfur oxides, nitrogen oxides, and acid deposition) H. Making coal a cleaner fuel i. It is possible to reduce sulfur emissions associated with the combustion of coal by installing scrubbers to clean the power plant s exhaust 1. Modern scrubbers remove 98% of the sulfur and 99% of the particulate matter in smokestacks 2. Desulfurization systems are very expensive ii. Selling the sulfurs or metals removed from polluted emissions as a marketable product is called resource recovery iii. The Clean Air Act Amendments of 1990 required the nation s 111 dirtiest coalburning power plants to cut sulfur dioxide emissions 1. This cut emissions by 3.8 million metric tons nationwide 2. The second phase of this amendment called for 200 additional power plants to make SO2 cuts by 2000 a. This reduced the total annual emission by 10 million metric tons nationwide b. A nationwide cap on SO2 emissions was imposed after 2000 iv. Clean coal technologies are new methods being developed for burning coal that will not contaminate the atmosphere with sulfur oxides and will significantly reduce nitrogen oxide contamination 1. Fluidized-bed combustion and coal gasification and liquefaction are two new clean coal technologies 2. These new technologies have little impact on reducing CO2 emissions IV. Oil and Natural Gas A. Beginning in the 1940s, oil and natural gas became increasingly important as energy sources due to easier transport and cleaner burning i. In 2005, oil and natural gas supplied 63% of the energy used in the U.S. ii. In 2004, oil and natural gas supplied 60.6% of the world s energy B. Petroleum (crude oil) is separated into gases, gasoline, heating oil, diesel oil, and asphalt during the refining process C. Oil is used to produce petrochemicals used in fertilizers, plastics, paints, pesticides, medicines, and synthetic fibers D. Natural gas is separated into propane, butane, and ethane; it costs four times more to transport through pipelines than crude oil i. Liquefied petroleum gas (propane and butane) is used as fuel for heating and cooking ii. Natural gas is used to produce both electricity and steam in a process called cogeneration 176

4 iii. Natural gas as a fuel for trucks, buses, and automobiles offers significant environmental advantages over gasoline or diesel E. Exploration for oil and natural gas i. Oil and natural gas deposits are usually discovered indirectly by the detection of structural traps; geological analysis to find structural traps is extremely expensive ii. Many important oil and natural gas deposits are found in association with salt domes F. Reserves of oil and natural gas i. Distribution is uneven; a large share of total oil deposits are clustered relatively close together (Persian Gulf region, Venezuela, Mexico, Alaska, etc.) ii. Almost half of the world s proved recoverable reserves of natural gas are located in Russia and Iran iii. Many countries engage in offshore drilling for oil despite problems such as storms at sea and the potential for major oil spills G. How long will oil and natural gas supplies last? i. Some experts think that global oil production has already reached Peak Oil (aka Hubberts Peak), others believe it will be reached around 2035 ii. About 80% of current production comes from oil fields discovered before 1973, and most of these have started to decline in production H. Global oil demand and supply i. The U.S. currently imports more than half of its oil; this dependence has potential international security implications as well as economic impacts ii. The imbalance between oil consumers and oil producers will probably worsen in the future because the Persian Gulf region has much higher proven reserves than other countries I. Environmental impacts of oil and natural gas i. Problems that result from burning fuels (combustion) 1. Every gallon of gas burned in a car releases an estimated 9kg of CO2 into the atmosphere; global warming results from increased CO2 in the atmosphere 2. Increased acid deposition, photochemical smog, and increased particulate matter result from combustion ii. Problems such as serious spills along transportation routes are involved in obtaining fuels V. Synfuels and Other Potential Fossil Fuel Resources A. Synfuels are fuels that are similar or identical to the chemical composition of oil or natural gas (i.e., tar sands, oil shales, gas hydrates, liquefied coal, and coal gas) B. Synfuels are more expensive to produce than fossil fuels C. Environmental impacts of synfuels i. Synfuels have many of the same undesirable effects as fossil fuels 1. Release of CO2 and other pollutants into the atmosphere 2. They require large amounts of water during production; limited usefulness in arid lands 177

5 ii. Large areas of land would have to be surface mined to recover the fuel in tar sands and oil shales VI. The U.S. Energy Strategy A. A comprehensive national energy policy should consider the following elements i. Increase energy efficiency and conservation ii. Secure future fossil fuel energy supplies iii. Develop Alternative Energy Sources iv. Meet the first three objectives without further damage to the environment B. How politics influences the national energy policy i. The Energy Policy Act of 2005 focuses largely on supporting energy research for fossil fuels ii. Subsidies continue 178

6 In-Class Activities: Instructor Notes for In-Class Activity 1 Title: Examples of Fossil Fuels. Time: Materials: Handouts: Procedures: 10 minutes prep; minutes in class Samples of fossil fuels (and charcoal, firewood, candles, etc). This can include camping propane, vials of different sorts of crude, diesel and gasoline (be sure to used approved containers!), pieces of coal (more than one kind, ideally), different sorts of charcoal, pressed firewood and other firewood. Alternatively, you may wish to bring images that can be accessed at industry websites. Have students inspect the different sorts of fossil and biomass fuels. Then have them, in groups of 3-5, make notes about color, weight, fluidity. Then have them research (using the text and internet resources) the advantages and disadvantages of the different fuels for different purposes. Some relevant attributes of fuels: Energy density Transportability Volatility Storability Some uses Vehicle fuel (cars, trucks, busses, ships, trains) Electricity generation Industrial heating and manufacture Have students think about and discuss why coal became the first major industrial fuel. Student Instructions: Specific Suggestions: Objectives: See above Be sure student understand what charcoal is, how it is created. In particular, be sure that they are aware that it is NOT a fossil fuel. Define fossil fuel, and distinguish between coal, oil and natural gas. 179

7 Instructor Notes for In-Class Activity 2 Title: Geography, Fossil Fuels and the Future Time: Materials: Handouts: Procedures: Student Instructions: Specific Suggestions: Objectives: 5 minutes prep; minutes in class Figures depicting coal, oil and natural gas resources by country Have students, working in groups of 3 4, look at which countries or regions have access to ANY or SOME fossil fuels. Have them pay particular attention to which less developed countries have little or no domestic energy resources. Then have them consider these questions, and report back to the class for a larger discussion: 1. Are domestic fossil fuel resources necessary for development? 2. What are the development options for a less developed country that has few if any domestic fossil fuel resources? 3. Do all highly developed countries have domestic fossil fuel resources? If not, where and how did they access the fuels used for development? See above Compare energy use in highly developed and developing countries. 180

8 Instructor Notes for In-Class Activity 3 Title: Phase I and Phase II Vapor Recovery Time: Materials: Handouts: Procedures: 5 10 minutes prep; minutes in class Old nozzle from a gasoline station (or images, available at vendor websites); images of gasoline trucks unloading at a local gas station. Better yet, get permission to tour a gas station while a truck is off-loading gasoline. In many areas, Phase I (capturing vapors from emptied underground tanks) and Phase II (capturing vapors in emptied automobile gas tanks) vapor recovery systems are required. Gasoline vapors can represent a significant contribution to the creation of ground level ozone. Most students are familiar with Phase II equipment, whether or not they are aware. As gasoline goes into an empty tank, vapors are forced out of the tank. These vapors can be captured by a sheath around the nozzle, and returned through a second hose (often integrated into the main hose), and from there back into the underground tank. Then, when the gasoline truck comes, as it empties, the vapors from the underground tank are returned to the truck. When the truck goes back to be filled, the vapors can be condensed into useable gasoline, or burned. Assignments from students: Inspect the nozzles and/or images. Take notes about the system design. Compare current designs with earlier designs Estimate the amount of gasoline that is used in your area in a day. For each gallon of gas pumped, at least one gallon of vapors will be released to the atmosphere if it is not captured. Student Instructions: Specific Suggestions: Objectives: See above Discuss the environmental problems of using oil. 181

9 Instructor Notes for In-Class Activity 4 Title: How much is left? Time: Materials: Handouts: Procedures: Student Instructions: Specific Suggestions: 5 10 minutes prep; 30 minutes Divide the class into three groups. Let them pick out of a hat which group they will be researching. You will have an OIL team, Natural Gas Team and a Coal Team. Their assignment is to prepare an obituary for their fuel and present it to the class. They might want to write it up in Newspaper format. You have been assigned a product either OIL, Natural Gas or Coal. The earth has just run out of this material and you are to write an obituary for this product. Be creative and informative. Some of the things you might mention in your research for this obituary is the time spent on earth, the value, who was helped or hurt by the existence of your product etc. Objectives: Define Fossil Fuel, and distinguish among coal, oil and natural gas. Discuss the advantages and disadvantages of coal, oil and natural gas. 182

10 Instructor Notes for In-Class Activity 5 Title: Diary of the energy you use Time: Materials: Handouts: Procedures: Student Instructions: Specific Suggestions: 5 10 minutes prep; 1 week out of class time Notebook Discuss with students the amount of energy used for an average household. Can we live without certain forms of energy produced from coal, oil and natural gas? Have the students keep a diary of the energy they use from the time they get up to the time they go to bed. They may need a small pocket notebook to keep with them so they can keep track of the energy they use not only at home but in school, to and from school, at their jobs etc. Take a small notebook that is easily kept with you and every time you use any form of energy by natural gas, coal, or oil, you will write it down with the time use and estimate how much was used. Note: You might check and see if your electricity is fueled by gas, coal or oil. Or you could put another line to monitor the amount of electricity used and do your calculations later. After you spend a week collecting data on your use of gas, oil Objectives: Describe the dependency on oil, natural gas and coal is it a reality in your area. Compare per capita energy consumption in highly developed and developing countries. 183

11 Answers to Thinking About the Environment End of Chapter Questions: 1. The Industrial Revolution may have been concentrated in the Northern Hemisphere because coal is located there. What is the relationship between coal and the Industrial Revolution? Ans: Although coal was used as a fuel for centuries, not until the 18th century did it begin to replace wood as the dominant fuel in the Western world. Since then, coal has had a significant impact on human history. It was coal that powered the steam engine and supplied the energy for the Industrial Revolution, which began in the mid-18th century. Today utility companies use coal to produce electricity, and heavy industries use coal for steel production. Coal consumption has surged in recent years, particularly in the rapidly growing economies of China and India, both of which have large coal reserves. 2. Few countries in Africa have significant amounts of coal, oil and natural gas resources. What does this suggest about opportunities for financial development in those countries. Ans: Africa, with the exception of a few countries, have few fossil fuel resources. Their only options for expanding energy use will be to purchase fossil fuels from other countries or develop alterative resources. Either of these approaches requires substantial financial capital another resource generally lacking in developing countries. This will result in limited financial development opportunities for many counties. 3. Does thinking of oil addiction literally, as depicted in Figure provide a useful way to get away from this addiction? Why or why not? Ans: Answers will vary. 4. How does U.S. dependence on foreign oil affect our energy security? Ans: This dependence of the U.S. on Middle Eastern oil has potential international security implications as well as economic impacts. The imbalance between oil consumers and oil producers will probably worsen in the future because the Persian Gulf region has much higher proven reserves than other countries. At current rates of production, North America's oil reserves will run out decades before those of the Persian Gulf nations. Given this situation it is important that the U.S. find ways to increase its energy security by reducing consumption or finding other sources. 5. On the basis of what you have learned about coal, oil, and natural gas, which fossil fuel do you think the United States should exploit in the short term (during the next 20 years)? Explain your rationale. Ans: Answers will vary. 184

12 6. Explain why the United States Department of Energy describes coal as a true measure of the energy strength of the United States. Is this also true of China? India? Why or why not? Ans: Answers will vary. 7. In your estimation, which fossil fuel has the greatest potential for the 21st century? Why? Ans: Answers will vary. 8. Which of the negative environmental impacts associated with fossil fuels is most serious? Why? Ans: Answers will vary. 9. Which major consumer of oil is most vulnerable to disruption in the event of another energy crisis: electric power generation, motor vehicles, heating and air conditioning, or industry? Why? Ans: Motor vehicles are most at risk for another energy crisis because they rely so heavily on gasoline. Electric power companies use coal to produce electricity, and heavy industries use coal for steel production. The United States has 25% of the world's coal supply in its massive deposits. Natural gas efficiently fuels residential and commercial air-cooling systems and well as heating systems. 10. What are the implications of Peak Oil on future global energy supplies? Ans: The most optimistic predictions are for Peak Oil at around After which point global oil supplies will decrease and energy needs will have to be met by other sources. Natural gas is more plentiful than oil. Experts estimate that readily recoverable reserves of natural gas, if converted into a liquid fuel, would be equivalent to between 500 billion and 770 billion barrels of crude oil, enough to keep production rising for at least 10 years after conventional supplies of petroleum have begun to decline. However, if the global use of natural gas continues to increase as it has in recent years, then its life supply will be much shorter than current projections predict. Analysts say the world must move quickly to develop alternative energy sources because the global demand for energy will only continue to increase. 11. Do you think oil drilling should be permitted in the Arctic National Wildlife Refuge? Why or why not? Ans: Answers will vary. Mr. Harder s opinion: NO! We must not disturb America s Serengeti. This ecosystem was protected for very good reasons and if oil is extracted, then it must be done without disturbing the ecosystem; AND IT CAN BE DONE. We must be patient and wait for technology to develop that will allow exploration remotely so that extraction can precede using horizontal drilling methods from pads outside ANWR. During the intervening years we can develop other energy approaches and hopefully when we do extract oil from ANWR it will be put to a higher use than combustion. 185

13 12. Some environmental analysts think that the latest war in Iraq was related in part to gaining control over the supply of Iraqi oil. Do you think this is plausible? Explain why or why not. Ans: Answers will vary. 13. Why does the United States currently have a growing shortage of natural gas? Ans: Natural gas is in increasing demand in the U.S. but deposits are often located far from where the energy is used. Because it is a gas and is less dense than a liquid, natural gas costs four times more to transport through pipelines than crude oil. To transport natural gas over long distances, it must first be compressed to form liquefied natural gas (LNG), then carried on specially constructed refrigerated ships. After LNG arrives at its destination, it must be returned to the gaseous state at regasification plants before being piped to where it will be used. Currently, the United States has only four such plants, which severely restricts the importation of natural gas from other countries. 14. What are the five kinds of synfuels? Why are they not being used more extensively? Ans: Synfuels include tar sands, oil shales, gas hydrates, liquefied coal, and coal gas. Although synfuels are promising energy sources, they have many of the same undesirable effects as fossil fuels. Their combustion releases enormous quantities of CO2 and other pollutants into the atmosphere, thereby contributing to global warming and air pollution. Some synfuels, such as coal gas, require large amounts of water during production and are of limited usefulness in arid areas, where water shortages are already commonplace. Also, enormously large areas of land would have to be surface mined to recover the fuel in tar sands and oil shales. 15. What is resource recovery? Ans: Resource recovery is the process of removing any material sulfur or metals, for example from polluted emissions or solid waste and selling it as a marketable product. 16. Distinguish among fluidized-bed combustion, coal liquefaction, and coal gasification. Ans: Fluidized-bed combustion is a clean-coal technology in which crushed coal is mixed with limestone to neutralize the acidic sulfur compounds produced during combustion. A nonalcohol liquid fuel similar to oil can be produced from coal, called coal liquefaction. The liquid fuel, which is cleaned before burning, is less polluting than solid coal. Coal gasification is production of the combustible gas methane from coal by reacting it with air and steam 17. Give three reasons why the United States needs a comprehensive national energy policy. Ans: The United States has a comprehensive energy policy for several reasons: (1) The supply of fossil fuels is limited; (2) the production, transport, and use of fossil fuels pollute the environment; and (3) our heavy dependence on foreign oil makes us economically vulnerable. 186

14 18. Fossil fuels are non-renewable resources. Why is this a problem from a systems perspective? Ans: Consuming fossil fuels at the current rate is not sustainable. We will use up our supply of these resources and be unable to replace them. Taking a systems perspective one that accounts for long term cause and effect relationships and sustainability might lead to a more efficacious energy policy. Answers to Review Questions Energy Sources and Consumption (p. 235) 1. How does per capita energy consumption compare in highly developed and developing countries? Ans: A conspicuous difference in per capita energy consumption exists between highly developed and developing nations. Highly developed nations consume much more energy per person than developing nations. Fossil Fuels (p. 237) 1. What are fossil fuels? Ans: Fossil fuels are combustible deposits in Earth s crust, composed of the remnants (fossils) of prehistoric organisms that existed millions of years ago. Coal, oil (petroleum) and natural gas are the three types of fossil fuel. 2. How are coal, oil, and natural gas formed? Ans: Areas where fossil fuels formed were vast swamps, rich in plant life. As the plants died, they fell into the swamp and were covered by water, where decomposition was slow. Over time, more and more dead plants piled up. As a result of periodic changes in sea level, layers of sediment accumulated, forming layers that covered the plant material. Aeons passed, and the heat and pressure that accompanied burial converted the nondecomposed plant material into a carbonrich rock called coal and the layers of sediment into sedimentary rock. Oil formed when large numbers of microscopic aquatic organisms died and settled in the sediments. As these organisms accumulated, their decomposition depleted the small amount of oxygen present in the sediments. The resultant oxygen-deficient environment prevented further decomposition. Over time, the dead remains were covered and buried deeper in the sediments. Natural gas composed primarily of the simplest hydrocarbon, methane, formed in essentially the same way as oil, only at higher temperatures, typically greater than 100 C. Coal (p. 243) 187

15 1. What are the advantages and disadvantages of using coal as an energy resource? Ans: The United States has 25% of the world's coal supply in its massive deposits. These supplies are projected to last at least 200 years at current consumption levels. However, coal mining poses risks to human health and environmental health. The burning of coal also releases many pollutants into the air. 2. Which type of coal mining-surface or subsurface mining-is more land-intensive? Ans: Surface mining disrupts the land much more extensively than subsurface mining and has the potential to cause several serious environmental problems. 3. What are acid mine drainage and acid deposition? Ans: Acid mine drainage is pollution caused when sulfuric acid and dangerous dissolved materials such as lead, arsenic and cadmium wash from coal and metal mines into nearby lakes and streams. Acid deposition is a type of air pollution in which acid falls from the atmosphere to the surface as precipitation (acid precipitation) or as dry acid particles. 4. What are the environmental benefits of resource recovery? of fluidized-bed combustion? Ans: In resource recovery the sludge is treated as a marketable product rather than as a polluted emission. These products can be sold to other industries and stay out of landfills. Fluidized-bed combustion takes place at a lower temperature than regular coal burning, and fewer nitrogen oxides are produced. Because the sulfur in coal reacts with the calcium in limestone to form calcium sulfate, which then precipitates out, sulfur is removed from the coal during the burning process, so scrubbers are not needed to remove it after combustion. Oil and Natural Gas (p. 251) 1. What are two examples of structural traps? Ans The strata that arch upward include both porous and impermeable rock. If impermeable layers overlie porous layers, any oil or natural gas present from a source rock such as shale may work its way up through the porous rock to accumulate under the impermeable layer. Many important oil and natural gas deposits are found in association with salt domes, underground columns of salt. The ascending salt dome, together with the rock layers that buckle over it, provides a trap for oil or natural gas. 2. What are three environmental problems associated with using oil and natural gas as energy resources? Ans: Two sets of environmental problems are associated with the use of oil and natural gas: the problems that result from burning the fuels (combustion) and the problems involved in obtaining 188

16 them (production and transport). The burning of oil and natural gas produces CO2. As CO2 accumulates in the atmosphere, it insulates the planet, preventing planetary heat from radiating back into space. Another negative environmental impact of burning oil is acid deposition. One of the concerns in oil and natural gas production is the environmental damage that may occur during their transport, often over long distances by pipelines or ocean tankers. A serious spill along the route creates an environmental crisis, particularly in aquatic ecosystems, where the oil slick can travel. 3. What is the controversy surrounding the Arctic National Wildlife Refuge? Ans: On one side are those who seek to protect rare and fragile natural environments; on the other side are those whose higher priority is the development of some of the last major U.S. oil supplies. Supporters cite economic considerations as the main reason for drilling for oil in the refuge. The United States is spending a large proportion of its energy budget to purchase foreign oil. Development of domestic oil would improve the balance of trade and make us less dependent on foreign countries for our oil. Conservationists think oil exploration poses permanent threats to the delicate balance of nature in the Alaskan wilderness, in exchange for a temporary oil supply. They reason that the money spent drilling for oil would be better used for research into alternative, renewable energy sources and energy conservation-a more permanent solution to the energy problem. Synfuels and Other Potential Fossil Fuel Resources (p. 252) 1. What are tar sands and oil shales? Ans: Tar sands, or oil sands, are underground sand deposits permeated with bitumen, a thick, asphalt-like oil. Oil shales are sedimentary rocks containing a mixture of hydrocarbons known collectively as kerogen. 2. What are liquid coal and coal gas? Ans: Through a process called coal liquefaction, a nonalcohol liquid fuel similar to oil can be produced from coal. The liquid fuel, which is cleaned before burning, is less polluting than solid coal. Coal gas is another synfuel, a gaseous product of coal. Coal gasification is production of the combustible gas methane from coal by reacting it with air and steam 3. How do the environmental problems associated with the use of synfuels compare to those of coal, oil, and natural gas? Ans: Although synfuels are promising energy sources, they have many of the same undesirable effects as fossil fuels. Their combustion releases enormous quantities of CO2 and other pollutants into the atmosphere, thereby contributing to global warming and air pollution. Some synfuels, such as coal gas, require large amounts of water during production and are of limited usefulness in arid areas, where water shortages are already commonplace. Also, enormously large areas of land would have to be surface mined to recover the fuel in tar sands and oil shales. 189

17 The U.S. Energy Strategy (p. 255) 1. What are subsidies? How do they affect energy prices and use? Ans: A subsidy is a form of government support (such as public financing or tax breaks) given to a business or institution to promote that group s activity. Subsidies keep energy prices artificially low because the government thinks they are beneficial to the economy. When prices reflect the true costs of energy, including the environmental costs incurred by its production, transport, and use, energy is used more efficiently. 2. What are the main points in President George W. Bush's National Energy Policy? Ans: President Bush s policy has five components: (1) modernize conservation; (2) modernize our energy infrastructure; (3) increase energy supplies; (4) accelerate the protection and improvement of the environment; and (5) increase our nation's energy security. 190