The Principles of Pumped Storage
Pumped storage hydro-electricity works on an extremely simple principle.
Two reservoirs at different altitudes are necessary. When the water is released, from the upper reservoir under gravity, 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 an electric 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 - In the example of Dinorwig's six generating units, they 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.
In effect this pumped storage system is a form of demand management, in short a "battery" of stored potential energy.
Dinorwig and Ffestiniog supply electricity to the Grid on a daily basis, as well as providing back-up for periods of heavy demand. The stations offer fast response times - in the case of Dinorwig, probably the fastest of any power facility in the world - 1,728MW from standstill n just 90 seconds.
Each of Dinorwig's six generating units can produce 288MW of electricity, offering a combined station output of 1728MW. Ffestiniog's four 90MW units have a combined generating capacity of 360MW.
About Dinorwig Pumped Storeage, Snowdonia, Wales
|Lower Dinorwig Reservior
|Detail from above