The state of Hawaii has a bold energy agenda: it plans to get 100% of its energy from renewable sources by the year 2045. In order to get there, Hawaii is embracing a diversified mix of renewable energy generation sources. Of course, Hawaii’s famous sunshine has allowed the state to have the highest per-capital base of installed solar power in the nation. But it will take more than just solar power for Hawaii to get all of its energy from green sources.
In August, Hawaii commissioned the first U.S. and world’s largest grid-connected ocean thermal energy conversion (or OTEC) power plant. The Makai OTEC plant produces 105 kW, enough to power about 120 homes with zero emissions. It is a relatively small system, but it represents a milestone.
OTEC makes use of the temperature differences between the surface of the sea and deeper water in order to generate electricity. The warm water evaporates a low boiling point liquid like ammonia and the pressurized vapor drives a turbine generator. Cold water pumped from lower depths condenses the ammonia and the cycle starts over. It is a promising technology for tropical locations. Unlike solar and wind power, OTEC can operate 24/7, making it a form of base-load, reliable power.
There are plans to build larger OTEC plants in Hawaii. A consortium of Japanese companies is going to build a 1 MW OTEC plant in Okinawa. The US Navy is very interesting in developing OTEC for its fleet operations. Once established, OTEC could be a cost-effective, reliable and clean way to provide a significant portion of Hawaii’s energy needs.
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First U.S. Grid-Connected OTEC Plant Goes Live on Hawaii
Photo, posted August 21, 2015, courtesy of Aki-Kumejima via Flickr.
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