Science: And Now It Is Pond Power

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Just 2.5 meters (8 ft.) deep and 7,000 square meters (70,000 sq. ft.) in area, the Ein Bokek pond produces 150 kilowatts of power. To generate more power, significantly larger ponds would be needed. Physicist Harry Tabor, chief architect of Israel's solar pond program, notes, for instance, that surfaces of large solar ponds must be crisscrossed with plastic baffles. These gridlike barriers prevent winds from churning up the water, which would mix the critical layers and diminish the pond's effectiveness as a heat collector. But Israeli officials, who hope to build a five-megawatt pond within two years, are confident that the difficulties in scaling up the ponds can be overcome. They are thinking of a whole network of solar ponds bordering the Dead Sea that could fill as much as a third of Israel's electrical needs by the end of the century. Estimated construction cost: about $2,000 per kw, about the price of some hydroelectric power plants.

The initial success of the Israeli program has awakened enthusiasm for solar ponds in the U.S. Under an agreement with Israel, a group led by Southern California Edison is planning a five-megawatt demonstration facility at the Salton Sea, in Southern California's Imperial Valley. Under Government funding, scientists will investigate other potential U.S. solar pond sites, including San Francisco Bay and Utah's Great Salt Lake. Though their estimate may be somewhat optimistic, solar pond boosters figure that the new technology could eventually meet as much as 12% of U.S. energy needs and even more in Third World countries.