Pumped storage power plants
Controllable power plants
By pumping water, pumped storage power plants are primarily used for absorbing surplus electrical power in the power grid during low demand periods, such as at night and at weekends. At times when there is a large demand for electricity, the stored energy is released to cover the peak loads in the power grid. In combination with other power plants, which are less or not controllable, they enable a more uniform utilisation.