5MW and above installed capacity
The Ffestiniog Power Station (Picture Right) is a 360Mw pumped-storage hydro-electricity scheme near Ffestiniog, in Gwynedd, North Wales. The power station at the lower reservoir has four water turbines, which can generate 360Mw of electricity within 60 seconds of the need arising. The station, commissioned in 1963, was the first major pumped storage system in the UK. The upper reservoir is Llyn Stwlan which can discharge 27 M3/s of water to the turbine generators at the power station on the bank of Tan-y-Grisiau reservoir.