At its peak, around 4,000 people worked on the construction project. 36 men died building the power station and dam. The scheme cost £24.5 million. Cruachan is one of four pumped storage schemes in the UK. The power station was originally operated by the North of Scotland Hydro-Electric Board, before transferring to the South of Scotland Electricity Board, now Scottish Power. Just last week Cruachan was purchased by Drax Group as part of a £702 million acquisition of Scottish Power assets. The upper reservoir sits 396 metres (1,299 ft) above Loch Awe. The station is capable of generating 440 megawatts of electricity from four turbines and can go from standby to full production in two minutes, or 30 seconds if compressed air is used to start the turbines spinning. When the top reservoir is full, Cruachan can operate for 22 hours before the supply of water is exhausted.