Ocean thermal energy
The energy that is generated using the difference between the temperatures of water at the surface of the ocean and at deeper levels is called ocean thermal energy.
To generate electricity, we use ocean thermal energy conversion (OTEC) power plants for which a temperature difference of 20 degrees Celsius between the surface water and the water at deeper levels is needed. In this process, the warm surface water of the ocean is used to boil a liquid such as ammonia or chlorofluorocarbon. The high-pressure vapours obtained are used to turn the turbine of a generator to produce electricity.