OTEC- Ocean Thermal Energy Conversion is a form of Solar Thermal Energy technology that essentally uses the ocean as a solar collector. OTEC takes advantage of the small temperature differential that exists between the warm surface of the sea and the cooler water at the bottom. In deep waters in excess of 1000 meters this difference is as much as 20 degrees C.
The oceans cover a little more than 70 percent of the Earth’s surface. This makes them the world’s largest solar energy collector and energy storage system. On an average day, 60 million square kilometers (23 million square miles) of tropical seas absorb an amount of solar radiation equal in heat content to about 250 billion barrels of oil. If less than one-tenth of one percent of this stored solar energy could be converted into electric power, it would supply more than 20 times the total amount of electricity consumed in the United States on any given day.
The economics of energy production today have delayed the financing of a permanent, continuously operating OTEC plant. However, OTEC is very promising as an alternative energy resource for tropical island communities that rely heavily on imported fuel. OTEC plants in these markets could provide islanders with much-needed power, as well as desalinated water and a variety of mariculture products.
Source: National Renewable Energy Laboratory