It is correct that a difference of 20 °C in temperature of water at two levels can be exploited to generate electricity. For this purpose, Ocean Thermal Energy Conversion (OTEC) power plants are used. To use this p1ant, a difference of 20°C or more between the temperature of surface waters and water at depths of 1000 meters is required. In one of Ocean Thermal Energy Conversion system, the warm surface water is used to boil low boiling liquid like ammonia, or a chlorofluorocarbon. The vapours of the liquid are then sent to move the turbines of generator. The cold water from the depths is used to cool the vapour escaped from the turbines and converted into liquid to be used again.
