 |  Environmental Science: A Global Concern, 7/e William P. Cunningham,
University of Minnesota
Mary Ann Cunningham,
Vassar College
Barbara Woodworth Saigo,
St. Cloud State University
Conventional Energy
BE ALERT FOR: Oil Price Sets Oil Supply
In the section on fossil fuels, you read references to estimated oil or gas reserves. Since these fuels are not renewable, it is important to know how much of these resources is actually available. That information, together with data on consumption rates, allows energy experts to determine how many years’ supply of a given resource remains.
Accurate determination of recoverable reserves of these materials is more complex than it may seem, however. In general, if the substance's price is low, removal of only the most accessible portions will be economical. The rest will not be considered recoverable in an economic sense. A low price will not stimulate extensive exploration to find new deposits, either. So, low prices tend to produce lower estimates of reserves.
If the price increases, however, two changes are likely. Formerly uneconomical supplies now become economically recoverable. Exploration will also be stimulated. So, as prices rise, new supplies are likely to be identified. The upshot of this is that the estimated quantity of economically recoverable oil, coal, gas, and other nonrenewable resources will always be subject to readjustment.
BE ALERT FOR: Atomic Energy
Nuclear power has had perhaps the most convoluted history of all our energy sources. Developed first as a weapon of war, conversion of atomic power to peaceful purposes was once hailed as the answer to humankind's energy needs. Rapidly accelerated costs, questions about where and how to dispose of the very dangerous, long-lived radioactive waste, and public skepticism and concern about safety reduced this earlier enthusiasm.
Here is how energy is obtained from atoms. A neutron strikes a uranium atom, releasing energy and sending additional neutrons off, which strike other uranium atoms. These atoms in turn split apart, releasing even more neutrons, which strike even more uranium atoms, and so on. When large numbers of uranium atoms are present and the chain reaction is allowed to proceed uncontrolled, a nuclear explosion results.
Nuclear reactors contain substances that absorb neutrons without splitting any additional atoms, thereby bringing the chain reaction under control. The tremendous amount of heat released by this process is used to turn water into steam. The steam turns turbines, generating electricity. Reactors need to be able to contain the heat and control the rate of nuclear bombardment to prevent the terrible runaway reactions and explosion that occurred at Chernobyl.
Spent fuel rods continue to be radioactive and will remain so for thousands of years. Safe, permanent disposal of this material has proven a tough problem to solve.
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2003 McGraw-Hill Higher Education