First Hydro Company

About Pumped Storage

Pumped storage hydro-electricity works on a very simple principle.

Two reservoirs at different altitudes are required. When the water is released, from the upper reservoir, energy is created by the downflow which is directed through high-pressure shafts, linked to turbines.

In turn, the turbines power the generators to create electricity.

Water is pumped back to the upper reservoir by linking a pump shaft to the turbine shaft, using a motor to drive the pump.

The pump motors are powered by electricity from the National Grid - the process usually takes place overnight when national electricity demand is at its lowest

A dynamic response - Dinorwig's six generating units can achieve maximum output, from zero, within 16 seconds.

Pump storage generation offers a critical back-up facility during periods of excessive demand on the national grid system.