Electric power towers and power lines at Hoover Dam, Lake Mead National Recreation Area, Nevada. Hoover Dam provides generation of low-cost hydroelectric power for use in Nevada, Arizona, and California. Hoover Dam generates more than 4 billion kilowatt-hours a year; enough to serve 1.3 million people. Hydroelectricity is a clean, renewable source of energy that does not result in air pollution, chemical runoff, or toxic waste disposal.