Pumped hydro storage is the only large energy storage technique widely used in power systems. For decades, utilities have used pumped hydro storage as an economical way to utilise off-peak energy, by pumping water to a reservoir at a higher level. During peak load periods the stored water is discharged through the reversible pump-turbines to generate electricity to meet the peak demand. Thus, the main idea is conceptually simple. Energy is stored as hydraulic potential energy by pumping water from a lower level to a higher level reservoir. When discharge of the energy is required, the water is returned to the lower reservoir through turbines that drive electricity generators.

Inspec keywords: hydroelectric generators; pumped-storage power stations; reservoirs; turbines; power generation economics

Other keywords: electricity generation; power system economics; reservoir; pumped hydro storage; reversible pump-turbines; energy storage; water pumping; hydraulic potential energy

Subjects: Pumped storage stations and plants