Hawaii’s new OTEC power plant harvests energy stored in warm ocean water

By Kelly Hodgkins Published August 27, 2015

Hawaii became the first state in the US to generate electricity from the thermal energy stored in ocean water using a new 105-kilowatt ocean thermal energy conversion (OTEC) plant on Big Island, reports Bloomberg. The OTEC plant cost $5 million to build and is the world’s largest power plant using this renewable and clean energy source. The project was funded and developed through a collaboration between Hawaii’s Makai Ocean Engineering, the U.S. Navy’s Office of Naval Research, and the Hawaii Natural Energy Institute (HNEI) at the University of Hawaii.

Ocean thermal energy uses the temperature difference between warm surface water and deep cold ocean water to drive a turbine that is used to produce electricity. Because it relies on surface heating from sunlight, the supply of ocean thermal energy is practically limitless, especially in tropical areas where the ocean’s surface water heats up quickly. Much like a fossil fuel plant, the OTEC system provides this energy in a steady stream that can be ramped up or scaled down quickly in response to demand. Not only is it a constant and clean energy source, the OTEC system also is capable of producing “a massive amount of energy,” claim Makai staff.

Makai Ocean Engineering Inc

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OTEC shows promise as a renewable energy source, with a a commercial OTEC plant potentially producing electricity at the rate of $0.20 per kilowatt-hour. A single commercial-scale plant also would prevent the burning of 1.3 million barrels of oil and the emission of a half million tons of carbon each year. Currently, though, the technology is still in the research stage with Hawaii’s new 105-kilowatt plant only generating enough electricity to power 120 homes. It would take 12 commercial-level plants to supply Hawaii with 100 percent of its power needs.

Despite its infancy, Makai Ocean Engineering believes the technology is poised to take off and has plans to build a larger 1-megawatt facility in Japan. The biggest hindrance to the technology’s expansion now is financial and not technical. The technology is reliable, but the company lacks the funds to move beyond its small pilot plants and develop a larger, more expensive commercial-scale operation.

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Kelly's been writing online for ten years, working at Gizmodo, TUAW, and BGR among others. Living near the White Mountains of…

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