An old hydroelectric power station in Snowdonia, Wales has been brought back on line after nearly 50 years. Croesor power station at Blaencwm, Gwynedd was constructed almost 100 years ago by Moses Kellow to supply power to local slate quarries. It served the needs of the slate quarries until their closure in 1933 and was then retained to feed electricity into the grid system. Various schemes were considered to enlarge the facility but it fell into disrepair in the 1950s. It has now been rehabilitated at a cost of over £1M (US$1.6M).

The redevelopment of the station at the head of the Croesor Valley was undertaken by National Power Hydro, which also operates Dolgarrog, Cwm Dyli, Dulyn and Cynwyd hydroelectric sites in North Wales.

The refurbished station has an installed capacity of 500kW. Helicopters were used to transport building materials and pipeline sections because of the difficult access to the site and to avoid ground damage. In addition a special ‘walking’ digger attached to the mountain by wire ropes was used to excavate the underground pipeline trench. The replacement power cables have also been installed underground, a task carried out by local electricity company Manweb.

Due to the historic nature of the site the original features of the station have been reused where possible. The original dam and hydro power plant site at Blaencwm was refurbished using local materials in keeping with the local environment.

Pat Montanaro, National Power’s director of Cogen and Renewables, said: ‘Croesor is the forerunner of further renovations, acquisitions and greenfield developments of small hydro plants planned by National Power as part of its drive to increase output from renewable sources of energy.’