Cruachan uses cheap electricity generated at night to pump water to the higher reservoir, which can then be released during the day to provide power as necessary.

[1][4] The civil engineering design of the scheme was carried out by James Williamson & Partners of Glasgow, and the main project contractors were William Tawse of Aberdeen and Edmund Nuttall of Camberley.

[11] Its construction was linked to that of Hunterston A nuclear power station, to store surplus night-time nuclear-generated electrical energy.

[12] To commemorate the 50th anniversary of the station's opening, a 2015 BBC radio documentary Inside the Rock described its construction.

[14] The Cruachan station temporarily stores energy at times of low demand, and releases it at times of high demand, when electricity prices are higher,[3] reducing the maximum power that must be provided by other power stations.

[3] Water is pumped from Loch Awe to the upper reservoir, 396 m (1,299 ft) above, during periods of low energy use (most often at night), and then released when needed.

[10][12][17] It can go from standby to full production in two minutes, or 30 seconds if compressed air is used to start the turbines spinning.

[25] Construction of the power station required the removal of 220,000 cubic metres (7,800,000 cu ft) of rock.

[2][3] The reservoir has a catchment area of 23 km2 (8.9 sq mi),[3] and is capable of holding 7 gigawatt-hours (25 TJ) of energy.

[29][30] The power station was listed by the conservation organisation DoCoMoMo as one of the sixty key monuments of post-war Scottish architecture.

The middle panel commemorates 15 workers killed when the roof of the turbine hall collapsed, and the final section shows the station working.

[32] In the Disney+ Star Wars series Andor episode six "The Eye", the Cruachan Power Station appeared as the Empire's supply hub on the planet Aldhani.