The surface of the earth to 70 percent, covered with water, which is vital to living beings. These waters are the change of status and circulating all the time. Between the earth's surface and the atmosphere continuously, which is called the water cycle. The water was moving with the energy is accumulated. The man known to bring energy and use this to hundreds of years, such as using rotated waterwheel. At present, the water power to rotate the turbine generator in hydroelectric power plant to produce electricity.