28 Year old article - Ocean Thermal Energy Conversion

[OKIsItJustMe]

http://www.motherearthnews.com/Renewable-Energy/1980-05-01/Ocean-Power.aspx

OCEAN POWER

Anne White-Clergerie reports on an attempt to plumb the world's largest solar collector:

Today—as energy shortages and escalating prices force us to accept the indisputable fact that man has nearly depleted the planet's store of fossilized solar power—it's apparent that we must rapidly change our methods of energy production and our habits of consumption. Windmills, biomass conversion centers, hydroelectric plants, and solar collectors are already being used to help us redirect our energy needs toward renewable sources. And, late last year, another benign method of harnessing the sun's power became a reality off the coast of Hawaii.

OTEC—or Ocean Thermal Energy Conversion is a hundred-year-old idea that was brushed aside during the years of fossil fuel abundance. However—under the pressure of our recent energy shortages—the concept has undergone a renaissance which could eventually make the oceans a significant source of both economical and environmentally sound power. By taking advantage of the natural difference in temperature between sun-warmed surface water and the chilly depths, OTEC is tapping our planet's largest solar collectors . . . the seas.

Electricity is generated in an ocean thermal plant through a Rankine (or condensation/vaporization) cycle. . . the same basic technique that air conditioners employ. However, OTEC combines warm and cold water to produce electricity instead of using electricity to separate warm and cold air. The theory is rock solid, but until recently OTEC was nothing more than a good idea.

Then, in early August of 1979, a converted U.S. Navy dump scow—moored in 3,000 feet of water off Keahole Point, Hawaii—became the world's first ocean thermal plant to produce more electricity than it consumed. So far, the barge isn't putting out much juice by power plant standards: Its total capacity is only 50 KW, and 10 KW of that wattage goes to plant operation . . . but it is a beginning! The floating power producer—designed and built by the State of Hawaii, Lockheed Missiles and Space Company, and the Dillingham Corporation—has demonstrated that OTEC is more than theory.

Admittedly, like Edison's first light bulb, Mini-OTEC's operation is feeble and sometimes cantankerous, but the real economical application of the concept is almost entirely a matter of upping the prototype's scale. From the titanium plate-type heat exchangers (donated by Alfa-Laval of Sweden) to the Rotoflow turbine/generator system, all of Mini-OTEC's hardware is off-the-shelf, state-of-the-art equipment. Similarly, her moorings consist of common materials such as polyethylene pipe . . . and her anchor is made of concrete.

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Where is OTEC today?
http://hawaii.gov/dbedt/info/energy/renewable/otec
http://www.otecnews.org/