Conon Valley Hydro Electric Scheme

The Conon Hydro Scheme, or Conon Valley Scheme, is a series of hydroelectric power stations located on the River Conon and tributaries in Scottish Highlands, between Inverness and Ullapool. The scheme was developed and built by the North of Scotland Hydro-Electric Board in three phases between 1946 and 1961. It is now operated by SSE Renewables. The scheme contains six power stations at Achanalt, Grudie Bridge, Mossford, Luichart, Orrin, and Torr Achilty. They have a total capacity of 107.2 MW and an annual output of around 470 GWh (or million units per year). Water is impounded in eight reservoirs by nine large dams. There is also a complex series of nine tunnels and many aqueducts to divert the water to the power stations, some coming from other river basin catchments. The first phase harnessed the catchment of Loch Fannich, diverting it through a tunnel to Grudie Bridge Power Station, which was constructed at the confluence of the River Guidie and River Bran, just upstream of Loch Luichart. Grudie Bridge started generating in 1950. Originally built without a dam on Loch Fannich, one was added five years later increasing the head and storage of the scheme. The second phase comprised four power stations. Mossford, which takes water via tunnels from Loch Glascarnoch and Loch Vaich, both of which were created by damming tributaries of the Black Water. Achnalt, on the River Bran downstream of Loch Achnalt and Loch a' Chuillin. Luichart, downstream of Loch Luichart which is supplemented by water from Loch Meig. Torr Achilty, the lowest power station in the scheme located in a dam across the River Conon forming Loch Achonachie. The third and final phase was to construct the Orrin Reservoir with two dams, plus a tunnel through the hillside to the power station on the shore of Loch Achonachie.