The Energy of a Temperature Gradient of Sea Water (ETGSW) — potentially the most powerful source of the electric power. Water of oceans at a depth even in the equatorial zones is very cool (generally 5–10 °C) while in blankets often happens quite warm (more than 25 °C). Such difference of temperatures arises literally on hundred meters of difference of depths and can be quite used for electrogeneration. By calculations, even extraction of 5% of energy of the Sun absorbed by oceans and the leader to a difference of temperatures in their layers, is capable to provide 10 000 GW of generating capacities — that is 80 trillion kW • h in a year that four times exceeds present world electrogeneration.
At coast of Hainan the difference of temperatures at a surface and at a depth exceeds 22 °C. (Here and lower than the illustration Lockheed Martin. )
But for realization of such system it is necessary to overcome a number of difficulties because of which the capacity of power plants on ETGMV yet doesn't exceed tens kilowatts. The concept of the Lockheed Martin company consists in the following: first, it is necessary to choose correctly the area of work of station — to achieve the maximum difference of temperature of superficial and deep layers; secondly, to use the optimum scheme on energy consumption. In the system offered by Lockheed Martin, ammonia in the heat exchanger evaporates in warm blankets; the evaporated gas twists the turbine and arrives in the lower part of the heat exchanger, being cooled with deep water and turning into liquid, then reused for energy generation. Parasitic losses on pumping of ammonia are equal here about 40% from received pure generation, and cost, by optimistical estimates of the company, there can be in the area only 7 cents for kilowatt-hour.
Such scheme is ideally suited for coastal areas and especially islands where energy generation often depends on imported fuel, and therefore is extremely expensive. So, cost on the Hawaiian Islands is equal (January, 2013) 37,86 cents for kW • h for households and 31,69 cents for industrial enterprises that, undoubtedly, force to rejoice small number of the last in this state of the USA. For comparison: these prices are equal in continental States pity 11,47 and 6,45 cents for kW • h respectively.
The offshore power plant on EGTMV is essentially enough simple, but while nobody built large stations of this kind, and Lockheed Martin here the pioneer.
For this reason in 2009 of Lockheed Martin was going to begin construction on Hawaii power plants on ETGMV on new technology (own development). But Naval Forces of the USA which partially financed the project, considered too risky to be put for themselves in it therefore on April 13, 2013 the company signed the corresponding memorandum of understanding with the Chinese Reignwood Group, planning to build up coastal areas of the island of Hainan.
Capacity of pilot station is equal 10 MWt, however, if experience is successful, it will be increased to 100 MWt. Unlike wind or solar energy, such installation is capable to work in full and identical force day and night, and each such station will be able to give enough energy to replace 1,3 million barrels of oil and to reduce emissions of carbon dioxide by half a million tons per year.