Pumped storage electrical power station - has pump, turbine and liquid and gas reservoirs deep underground

摘要

1000 metres below the earth's surface is a first storage space (1) filled with a liquid (9) which has a high density, e.g. 1200 kg per cubic metre. At a depth of 1500 metres is a second storage space (4) partially filled with a gas, e.g. propane, nitorgen, etc. which is kept under high pressure, e.g. 200 bar by the outlet (11) of a compressor. The storage spaces are connected by a pipe (12) to equalise gas pressures. During the night, low cost electricity is used to power a pump (6), which draws the liquid up from the lower (4) to the higher (1) storage space. During the day, when electrical demand is at a peak, the liquid is allowed to flow back to the lower space, via the pump (6) which then acts as a turbine powered electrical generator. If required, the pump can be powered using natural gas in place of an electric motor.