With Ocean Thermal Energy Conversion, electricity is generated solely by using the difference in temperature between cold deep sea water and warmer surface water. No continuing outside energy source is needed.
But there’s more.
Electrical energy generation, despite being the obvious application of OTEC technology, is not it’s only benefit. The cold deep ocean water can be used as a coolant in air conditioning systems instead of simply pouring it back into the ocean after use in an OTEC system. In fact such a system has been in operation in NELHA for some time. Deep ocean water is rich in nutrients and could be used to cultivate marine organisms in Aquaculture farms.
Chilled-soil agriculture can also benefit from OTEC. Spent deep ocean water from the OTEC system flows through pipes embedded in the ground. This cools the surrounding soil and allows plants that would normally wither in subtropical climates to thrive.
Hawaii is pioneering OTEC research. Perhaps one day soon they will create most of their energy in their offshore waters rather than by importing fossil fuels.