Hydroelectric power, or hydroelectricity, is generated by the force of falling water. (Hydro comes from the Greek word for water.) Its one of the cleanest sources of energy, and its also the most reliable and costs the least. That means that TVA’s hydroelectric power plants are able provide electricity at a reasonable cost to families, schools, farms, factories, and businesses.
How does hydroelectric power work?
Water is needed to run a hydroelectric power-generating unit. The water is held behind a dam, forming an artificial lake, or reservoir. The force of the water being released from the reservoir through the dam spins the blades of a giant turbine. The turbine is connected to the generator that makes electricity as it spins. After passing through the turbine, the water flows back into the river on the other side of the dam.
TVA uses water to make electricity at 29 hydroelectric dams and one pumped-storage power plant (at Raccoon Mountain near Chattanooga, Tennessee). Together these plants produced about 12.7 million megawatt hours of electricity in 2011, enough electricity to power about a million homes for a year.