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World's Newest Form of Marine Renewable Energy Launched in Hawaii

It's called Ocean Thermal Energy Conversion, or OTEC, and the world's largest plant was dedicated in Hawaii on August 21. It produces renewable energy by using the temperature difference between the ocean's deep cold water and warm surface water.
August 31, 2015, 9am PDT | Irvin Dawid
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Emission-free energy is now being produced in Hawaii by Makai Ocean Engineering, thanks to funding by the Office of Naval Research through the Hawaii Natural Energy Institute," states Makai's news release. The $5 million, 105-kilowatt demonstration plant on the Big Island "only generates enough electricity to power 120 homes," writes Cole Mellino for EcoWatch. "But to date, it’s the largest such plant in the world."

Corrosion Facility

Credit: Makei Ocean Engineering

The company estimates that all of Hawaii’s electricity needs could be met by about 12 commercial-scale OTEC plants. They already have plans to construct a 1-megawatt facility in Japan.

“Anywhere tropical with deep water is ideal, especially if they import their fuel,” says Duke Hartman, vice president of business development at Makai.

While technically classified as a type "marine renewable energy," it's actually a form of solar energy, captured by the ocean and converted to electricity. "That’s beautiful because we can extract that energy 24/7 and use that power any time we want it, totally eliminating the need for an energy storage system,” states Hartman.

"Heat exchangers are really the key component to OTEC," states Hartman in this five-minute YouTube video as he point to the three pipes, standing on top of the plant.


Credit: Makei Ocean Engineering

"OTEC is a technology that the Navy has a significant interest for generating power at Naval bases around the world," states the naval research paper, "Understanding Predictability of the Ocean" [PDF]. "By using an [sic] Rankine engine cycle with fluorine gas cooled by deep ocean water and warmed by surface waters, turbines are used to generate electrical power that is sent back to shore."  [The video explains it in more detail.].

"The breakthrough marks the first true closed-cycle OTEC plant to be connected to a U.S. electrical grid, and represents a major achievement for Hawaii, the United States, and marine renewable energy," according to the news release.

The biggest challenge remains will be funding. "We need a visionary investor to get us past the expensive pilot project into the large-scale commercial projects," states Hartman.

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Published on Wednesday, August 26, 2015 in EcoWatch
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