Pumped Storage Dam

Another application of hydroelectricity is Pumped-storage hydroelectricity which does not create a net gain in power but enables peak demand balancing. Water is pumped from a lower elevation source into a higher one and only released through generators when electric demand is high. In 2009 the United States had 21.5 GW of pumped storage generating capacity, accounting for 2.5% of baseload generating capacity. Bath County Pumped Storage Station is the largest such facility in the world. Other stations of this type include Raccoon Mountain Pumped-Storage Plant, Bear Swamp Hydroelectric Power Station and Ludington Pumped Storage Power Plant on Lake Michigan and previously the largest in the world.