How Does Hydroelectricity Work?


Quick Answer

Hydroelectricity uses water to drive hydroelectric turbines connected to generators to create electricity. The electricity is transmitted via high-voltage power lines to a power network for distribution to homes and businesses.

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Full Answer

Hydroelectricity starts with a river that is flowing from an upland source through a valley that can contain a lake once the dam is built. The higher the elevation change, the greater the potential hydroelectric power that can be generated. Once the dam is built and the lake is filled, the hydroelectric dam can begin operation. Water is directed through channels in the dams past electric turbines. The turbines spin magnets inside generators which in turn generate electricity.

Water stored in the lake has tremendous potential energy. This potential energy is converted to kinetic energy by the drop from the height of the lake through the dam. As energy needs change throughout the day, more generators can be turned on or off, storing the water for later use. Many rivers have several dams on them, which allows the water that leaves the dam upstream to be reused in subsequent downstream dams. Water levels in the lakes behind dams are closely monitored and require consistent rain upstream to replenish the stored water. During severe droughts, some dams do not operate due to insufficient water.

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