A dynamic energy storage solution, pumped storage hydro has helped ‘balance’ the electricity grid for more than five decades to match our fluctuating demand for energy. Pumped storage hydro (PSH) involves two reservoirs at different elevations.
Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. A PSH system stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation.
During periods of low energy demand on the electricity network, surplus electricity is used to pump water to the higher reservoir. When electricity demand increases, the stored water is released, generating electricity. Pumped storage hydro (PSH) must have a central role within the future net zero grid.
The upper reservoir, Llyn Stwlan, and dam of the Ffestiniog Pumped Storage Scheme in North Wales. The lower power station has four water turbines which generate 360 MW of electricity within 60 seconds of the need arising. Along with energy management, pumped storage systems help stabilize electrical network frequency and provide reserve generation.
Pumped hydro involves pumping water uphill at times of low energy demand. The water is stored in a reservoir and, in periods of high demand, released through turbines to create electricity.
The basic operating principle is similar for all of them: water flows through a turbine to generate electricity. However, unlike run-of-river or reservoir power plants, pumped storage plants enable us to store and schedule hydroelectric power generation, while also playing a crucial role in stabilizing the power grid.