Close-up of a power control switch on the back of one of the hydro turbines inside the machine hall of the Cruachan Power Station, Scotland, UK, showing the four hydro turbines. This pumped-storage hydroelectric power station takes water between Cruachan Reservoir to Loch Awe, a height difference of 396 metres. The turbine hall is located inside Ben Cruachan, a 1126 metres high mountain, and houses four Francis turbines, which operate both as pumps and generators, capable of generating 440 MegaWatts of electricity.