Tapping Power from the Oceans
		by Robert Frenay The old nuclear-industry dream of "power too cheap to meter" didn't turn out so well. But ocean thermal-energy conversion (OTEC) looks more promising. Globally, deep ocean water averages 42 degrees Fahrenheit--the temperature inside most refrigerators--even when surface temperatures reach 80 degrees. That made John Craven wonder. Craven is a former dean of marine programs at the University of Hawaii, and before that he headed the Navy's Deep Submergence Systems Project. In 1974, a year after the Arab oil embargo, he got state funds for a research lab at Keahold Point, located on the big island of Hawaii, and began looking into natural and renewable energy sources. One of the lab's first projects, based on a 19th-century concept, was OTEC. Craven and his colleagues anchored an old barge off Keahole Point and dropped a two-foot pipe 2,700 feet into the ocean. With heat from surface water, they vaporized ammonia and used the vapor to run a small turbine. Power generated by the turbine drove electric pumps that drew water from the ocean floor. Then cold from the deep water recondensed the ammonia vapor, which was fed back into the cycle as a liquid. The device supplied the power to run its own pumps and produced a 15-kilowatt surplus as well--more than enough to maintain a typical household. A similar, land-based system, using a vacuum to make steam from warm surface water instead of ammonia, now produces 50 kilowatts of surplus power for the lab and some unexpected benefits. Today, a small community of research and business ventures crowd the state-sponsored site, using the cold, nutrient-rich water for everything from air conditioning to lobster farms to gardens. Program manager Tom Daniel maintains that someday "ten thousand OTEC plants spread across the tropics could produce ten terrawatts of electricity"--roughly all the power humans now use. Of course, distributing it would be a problem, and we'd have to avoid warming the oceans. But that, Daniel says, "is in the future." Tell us which new technology is most significant to you? Discuss it! What do you think about this article? This is important, I want more I found it interesting Ehh, it was OK It's not that significant I don't care Subscribe Now!
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