All energy sources have their environmental drawbacks.
"There is no human activity that is pollution-free," says Denis Beller, a visiting scientist at the center for environmental studies at the University of Nevada in Las Vegas.
The Bush administration's energy plan, combined with the California power shortage and concerns about global warming, has revived discussion of the pros and cons of various energy sources.
Mr. Beller and author Richard Rhodes have looked at the environmental impact of major energy sources. Like the authors of the Bush plan, Beller and Mr. Rhodes end up as fans of nuclear power.
Their findings are intriguing, maybe surprising.
Coal, used to generate electricity, is the worst environmental offender. For instance, the Harvard School of Public Health maintains that particulates from coal burning are responsible for about 15,000 premature deaths annually in the United States.
By comparison, 4,000 people who took part in the cleanup attempt after the 1986 accident at the Chernobyl nuclear plant in the Soviet Ukraine have died so far. Another 40,000 involved became ill or were disabled.
Coal plants are the major source of the acid rain that troubles the eastern US and Canada.
Less well-known is the fact that coal-fired power plants are the major source of radioactive releases into the environment.
When coal is burned, mildly radioactive uranium and thorium in it are released into the air. So is radioactive radon gas, a decay product of crustal uranium normally confined underground.
A 1,000-megawatt (MW) coal plant releases 100 times more radioactivity than a comparable nuclear plant. Of course, critics of nuclear plants worry about an accident releasing a huge plume of radioactivity. But none of the 420 operating power reactors worldwide have had an accident nearly as serious as that at the Chernobyl plant, which lacked a containment vessel.
A coal plant releases about 74 pounds of uranium-235 each year, enough for two or more nuclear bombs.
This material could be collected and processed from coal ash, perhaps without attracting much attention.
More radioactive heavy metal is released into the environment every two years by coal burning than the total spent fuel waiting to be buried from all US nuclear power production and most US nuclear-weapons production.
Coal supplies about 24 percent of world's energy needs. Natural gas provides 22.1 percent, and this percentage is expected to grow in coming years.
Natural gas is relatively clean burning. A 1,000 MW plant, for example, releases per day into the air "only" 5.5 metric tons of sulfur oxides, 21 tons of nitrogen oxides, 1.6 tons of carbon monoxide, and 0.9 tons of "particulates."
Natural-gas fires and explosions offer significant risks. Newspapers sometimes record houses and pipelines blowing up. A single mile of three-feet-diameter gas pipeline at 1,000 pounds per square inch pressure contains the equivalent of 1.32 million pounds of TNT - a lot of explosive energy.
A million miles of such gas pipelines lace the earth. The Bush plan calls for many more miles to take gas to market.
In an essay that appeared in an edited form in Foreign Affairs, Messrs. Beller and Rhodes also note that renewable energy sources have problems.
Hydropower submerges large areas of land, often displaces rural population, kills fish, and raises a risk of catastrophic failure. Dams, costly to build, also eventually silt up.
The making of photovoltaic cells produces a highly toxic waste stream of metals and solvents that requires special disposal technology. A 1,000-megawatt solar plant would generate 6,850 metric tons of hazardous waste over a 30-year lifetime from metals finishing alone.
A global solar-energy system would consume at least 20 percent of world iron resources. A huge volcanic eruption, such as the Krakatoa event of 1883, would temporarily put solar power out of business.
Wind farms need millions of pounds of concrete and steel, cause noise pollution, and slay many birds.
Beller approves of efforts to improve efficiency in producing and using electricity. But he says efficiency won't fully meet the needs for more energy. Nor will conservation. The power saved by conservation, often heavily subsidized, is twice as expensive in the US as generated power.
Nuclear power releases no noxious gases. A ton of nuclear fuel produces energy equivalent to 2 million to 3 million tons of fossil fuel. Generating 1,000 MW of electricity for a year requires 2,000 train cars of coal or 10 supertankers of oil, but only one 10-cubic-meter fuel assembly of uranium. A nuclear plant releases less radioactivity per person than a television set.
(c) Copyright 2001. The Christian Science Monitor