Pumped Hydro is an energy storage technology that uses the gravitational potential energy of water to store electricity from the grid.
During low demand for electricity, or when there is surplus electricity on the grid, water is pumped from a lower reservoir to an upper reservoir at a higher altitude and is stored there until needed. During periods of high demand, the water is released to flow through a turbine to generate electricity to be used on the grid.
Increasing generation by renewables is driving increased demand for flexible generation and energy storage in the UK. The new Glyn Rhonwy Pumped Hydro project seeks to help the UK develop a sustainable and secure electrcity system.