 The denser cold water masses, formed by ocean surface water interaction with cold atmosphere in quite specific areas of the North Atlantic and the Southern Ocean, sink into the deep sea basins and spread in entire deep ocean by the thermohaline circulation.Upwelling of cold water from the deep ocean is replenished by the downwelling of cold surface sea water.Among ocean energy sources, OTEC is one of the continuously available renewable energy resources that could contribute to base-load power supply.