Heimifeng Pumped Storage Power Station
The Heimifeng Pumped Storage Power Station () is located at the hills of Heimifeng, Qiaoyi town, Wangcheng district, north of Changsha in Hunan province, China. It was constructed between 2005 and 2009 with the generators being commissioned in 2009 and 2010. The station generates power by transferring water between an upper and lower reservoir. When energy demand is high, water from the upper reservoir is released and used to generate electricity before being discharged into the lower reservoir. During times of low demand, water from the lower reservoir is then pumped back up to replenish upper  reservoir. This process allows the station to meet peak energy demand and it can go from standstill to operational in three minutes. The upper reservoir is located at an elevation of formed by two main dams and two auxiliary dams. The main dams are and high concrete-face rock-fill dams (CFRD). Helping to support the reservoir is an additional CFRD and a tall gravity dam. The upper reservoir has a storage capacity of . The lower reservoir sits at an elevation of and is north of the lower reservoir. It is created by a tall rock-fill dam which withholds  a reservoir of . Located in the underground power station is four reversible Francis pump turbines. The difference in elevation between the two reservoirs affords a hydraulic head of . The station generates 1.606 billion kWh annually and consumes 2.16 billion kWh in pumping mode. The plant is profitable because pumping occurs during low demand periods when electricity is cheap.