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ocean thermal energy conversion
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| Diagram of the open-cycle ocean thermal energy conversion system at Keahole Point, Hawaii, which, in May 1993, produced a record-breaking 50,000 watts of electricity during a net power-producing experiment. Credit: NREL
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The process or technologies for producing energy by harnessing the temperature differences (thermal gradients) between ocean surface waters and that of ocean depths, which may be as much as 20°C. Warm surface water is pumped through an evaporator containing a working fluid, such as ammonia, in a closed Rankine-cycle system. The vaporized fluid drives a turbine/generator. Cold water from deep below the surface is used to condense the working fluid.
Open-cycle OTEC technologies use ocean water itself as the working fluid. Closed-cycle OTEC systems circulate a working fluid in a closed loop. A working 10 kilowatt, closed-cycle prototype was developed by the Pacific International Center for High Technology Research in Hawaii with U.S. Department of Energy funding, but was not commercialized.
Related category
• WATER POWER
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