Ffestiniog Power Station, Tanygrisiau

Ffestiniog Power Station, Tanygrisiau

The rectangular building beside Llyn Tanygrisiau, the lake here, is the UK’s first major pumped-storage power station. It opened in 1963.

Water from Llyn Stwlan, a reservoir in the mountains above the power station, generates electricity as it falls towards Llyn Tanygrisiau through four concrete-lined tunnels. Working together, the station’s four generating units can produce 360MW of electricity – enough to supply North Wales’ entire power needs for several hours. In practice, much of the power is transported by the National Grid for use in the UK generally.

When demand for electricity is low, usually at night, water is pumped back up to Llyn Stwlan – where it will be ready to generate electricity again when required. The pumps are driven by electricity which is produced at other UK power stations.

The facility is owned by First Hydro Company (First Hydro Company is jointly owned by GDF Suez and Mitsui & Co., Ltd), which also operates a larger pumped-storage system – open to visitors – in Llanberis.

Llyn Tanygrisiau was enlarged in the 1960s for the extra volume of water involved, flooding the trackbed of the derelict Ffestiniog Railway. When the railway was rebuilt in the 1970s, a new route was created behind the power station. It crosses the four water pipes on bridges before descending on a spiral to rejoin the original route at Dduallt.

Postcode: LL41 3TP    View Location Map

Power station website

Ffestiniog Railway Tour label Navigation away from Porthmadog buttonNavigation towards Porthmadog button