From time of creation of a mill the man uses water as a source of energy. Energy of falling water now is widely used on usual hydroelectric power stations. But recently people have begun to use energy of flows and waving; thermal underground waters are developed, at last, and in an experimental mode give the electric power of installations using a difference in temperature between warm top and cold deep layers of ocean. The rivers and seas have a huge stock of a thermal energy, which are used wider and wider now.

Water itself can also be a source of energy, exactly its component - hydrogen. The father of a science fiction Jul Vern in his novel "Mysterious Island " has predicted an epoch "of hydrogen power ": " The day will come, and water will replace fuel: the hydrogen and oxygen, which it consists of, will also be applied separately; they will appear inexhaustible and such a powerful source of heat and light, that coal is far away from them far ". According to a heat ability on a unity of weight, the hydrogen is 2,5 times surpasses natural gas and 3 times - petrol. At hydrogen burning, water is formed, and it is possible to receive hydrogen from it again - this is the simple principle of ecological circulation of energy. Still the man could not " build into" his power systems in natural circulation, though he has made his first steps in this direction.

Already there are projects of "hydrogen" planes, а "hydrogen" cars even exist in real execution. Since October, 1984 10 automobiles of the Mercedes mark passed tests in Western Berlin, half of the cars partially, and other half completely have worked on hydrogen fuel. Here is practically only one problem - the storage of a stock of hydrogen fuel, as cylinders are a too bulky system. Now people try to use ability of metals and metal alloys to accumulate in internuclear space a huge amount of hydrogen, connecting it temporarily with formation of hydride. At heating hydride liberates hydrogen.