The Bailianhe Pumped Storage Power Station is a pumped-storage hydroelectric power station located 58 kilometres (36 mi) east of Huanggang in Hubei Province, China. It was constructed between 2004 and 2009 and has a 1,200 megawatts (1,600,000 hp) installed capacity. The power station operates by shifting water between an upper and lower reservoir to generate electricity. For this project, only the upper reservoir had to be created as an existing reservoir, the Bailianhe Reservoir, was used as the lower. During periods of low energy demand, such as at night, water is pumped from Bailianhe Reservoir up to the upper reservoir. When energy demand is high, the water is released back down to the lower reservoir but the pump turbines that pumped the water up now reverse mode and serve as generato