chapter 12Review
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In this chapter, we have examined the nonrenewable fossil fuels that are used around the world and in the United States. We observed that energy use varies widely in different countries. Fossil fuel resources are used for different purposes and electricity draws 40 percent of U.S. energy demand. In the United States, oil, natural gas, and coal, in that order, meet 82 percent of the nation’s energy requirements. Each fossil fuel has its own advantages and disadvantages. Nuclear fuels, which generate 20 percent of the electricity in the United States, have their own set of advantages and disadvantages. One reasonable conclusion is that all energy choices have adverse consequences.
Module 34 Patterns of Energy Use
Describe the use of nonrenewable energy in the world and in the United States.
Energy use has changed over time along with the level of industrial development in a country. The United States and the rest of the developed world have moved from a heavy reliance on wood and coal to other fossil fuels and nuclear energy. The developing world still relies largely on wood, charcoal, and animal waste.
Explain why different forms of energy are best suited for certain purposes.
Each source of energy is best suited for certain activities, and less well suited for others. Energy efficiency is an important consideration in determining the environmental impacts of energy use. In general, the energy source that entails the fewest conversions from its original form to its end use is likely to be the most efficient.
Understand the primary ways that electricity is generated in the United States.
Electricity generation plants convert the chemical energy of fuel into electricity. Coal, oil, natural gas, and nuclear fuels are the energy sources most commonly used for generating electricity. The electrical grid is a network of interconnected transmission lines that tie power plants together and link them with end users of electricity.
Module 35 Fossil Fuel Resources
Discuss the uses of coal and its consequences.
Coal is an energy-
Discuss the uses of petroleum and its consequences.
Petroleum includes both crude oil and natural gas. The United States uses more petroleum than any other fuel, primarily for transportation. Petroleum produces air pollution as well as greenhouse gas emissions. Oil spills are a major hazard to organisms and habitat.
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Discuss the uses of natural gas and its consequences.
Natural gas is a relatively clean fossil fuel. The presence of natural gas pipelines makes natural gas a convenient fuel for electricity generation, home heating, and manufacturing processes as well as fertilizer production. Hydraulic fracturing has greatly increased the availability of natural gas in the United States.
Discuss the uses of oil sands and liquefied coal and their consequences.
Oil sands and liquefied coals have the potential to become more important in the U.S. energy portfolio but both require relatively large energy inputs to be obtained and processed into a usable form.
Describe future prospects for fossil fuel use.
Most observers believe that oil production will begin to decline sometime in the next few decades. The transition away from oil will have important environmental consequences, depending upon how quickly it occurs and whether we move to renewable energy resources or alternative fossil fuels.
Module 36 Nuclear Energy Resources
Describe how nuclear energy is used to generate electricity.
In nuclear fission, a neutron strikes a relatively large atom such as uranium, and two or more smaller parts split off, releasing a great deal of energy. This energy is used to convert water into steam, which turns a turbine, which then turns a generator. A small amount of nuclear fuel can release a great deal of energy and generate a large quantity of electricity.
Discuss the advantages and disadvantages of using nuclear fuels to generate electricity.
All forms of energy have advantages and disadvantages. Considering only emissions during electricity generation, nuclear energy is relatively clean. However, the construction of nuclear power plants and the mining of uranium both use fossil fuels. The major environmental hazards of electricity generation from nuclear energy are the potential for accidents during plant operation and the challenges of radioactive waste disposal.