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THE EARTH'S HEAT. Pacific Gas & Electric Co. operates the U.S.'s only geothermal plant, at the Geysers in California's Sonoma Valley. There, the engineers capture sulfurous, superheated steam hissing from natural vents and drilled wells in the earth's surface and use it to drive turbines. There is some question whether such techniques would work where there are no natural vents. The Los Alamos National Laboratory is now trying to exploit the dry, hot (600° F.) granite that underlies most of the earth. Scientists plan to sink two holes 15,000 ft. deep, then pump cold water down one well and let hot steam flow up the other. If successful, the dry-rock system might provide, says one scientist, "all the electricity America will need for the next 3,000 years."
SUNSHINE. Theoretically, the sun's energy ought to be usable, but no one is sure how best to collect sunshine and transform it into power. In answer, Aden and Marjorie Meinel of the University of Arizona have proposed a "solar farm" that would cover 5,500 sq. mi. of desert with rows of black steel bands. These would absorb the sun's heat and send it to large storage "batteries" of molten salt, which would power turbine generators. Cost of building a 3,000-kw. demonstration plant: $10 million. Despite the amount of land that such projects would take, most scientists agree that, given research funds, solar power will be economical and efficient in the not-too-distant future.
OTHERS. Windmills have long provided limited power in the flat, open countryside, and the wind's force could also be tapped from tall towers anywhere. The big problem, again, is how to store the energy from this variable source. Other proven possibilities include harnessing the oceans' tides (a limited possibility at best), burning garbage as a low-grade fuel and, strangest of all, combining animal manure and carbon monoxide under heat and pressure to produce oil. Government researchers reckon that they can get three barrels of oil from every ton of manure, but the costs of collecting the stuff and hauling it to a plant may prove prohibitive.
"We should be spending $2 billion a year on research into the alternatives, not $600 million," says Energy Consultant Freeman. "We're going into the future with only one arrow for our bow, the breeder. If it doesn't work out, we'll face a real crisis." Actually, the utilities have already proposed various surcharges that would raise some $400 million a year entirely for future research.