Hawaii has installed a fully closed-cycle Ocean Thermal Energy Conversion (OTEC) plant, which is the first in the U.S. It was funded by the U.S. Office of Naval Research and developed by Makai Ocean Engineering, a Hawaii-based design and engineering company. At a cost of nearly $5 million, the 100-kilowatt plant will power about 120 residences.
OTEC produces electricity by using deep cold ocean water and warm surface waters. The plant pumps large quantities of cold ocean water and warm surface water to run a power cycle through a steam-driven turbine, which produces electricity at an onshore power station.
While OTEC plants are still limited in the number of homes it can power, Makai maintains that these type facilities have immense potential. Nearly 70 percent of the sunlight is captured by the oceans and the surface layers absorb most of the ultra-violet energy. With sunlight a limitless resource, OTEC plants can extract the energy and does not require storage systems.
Hawaii currently imports almost all of its energy, but has a goal to use 100 percent renewable energy by 2045. Hawaii has already installed several wind power plants and smart grid systems in an effort to achieve this lofty goal.
The United States entered OTEC research in 1974 with the establishment of the Natural Energy Laboratory of Hawaii Authority. The U.S. Naval office considers this project as a prototype. Makai says the next hurdle is to secure investment and develop a commercial-scale plant.
In 2013, Japan’s Saga University constructed the first OTEC plant off of the Okinawa prefecture in the East China Sea. The Okinawa project generates about 50 kilowatts of electricity.
Currently, there are additionally OTEC plants proposed for development in the U.S. Virgin Islands, Bahamas, Hainan and Japan.
Click here for Makai’s OTEC report.