Ocean Thermal Energy Conversion (OTEC) is an energy technology that converts solar radiation to electric power. OTEC systems use the ocean's natural thermal gradient—the fact that the ocean's layers of water have different temperatures to drive a power-producing cycle. As long as the temperature between the warm surface water and the cold deep water differs by about 20°C (36°F), an OTEC system can produce a significant amount of power, with little impact on the surrounding environment. The distinctive feature of OTEC energy systems is that the end products include not only energy in the form of electricity, but several other synergistic products. The principle design objective was to minimize plan cost by minimizing plant mass, and taking maximum advantage of minimal warm and cold water flows. Power is converted to high voltage DC, and is cabled to shore for conversion to AC and integration into the local power distribution network. The oceans are thus a vast renewable energy resource, with the potential to help us produce billions of watts of electric power.Oceans cover more than 70% of Earth's surface, making them the world's largest solar collectors. The sun's heat warms the surface water a lot more than the deep ocean water, and this temperature difference creates thermal energy. Just a small portion of the heat trapped in the ocean could power the world.