• Category: Renewables
  • Energy type: Hydro
  • Project type: Asset

Foyers Pumped Storage Power Station is located on the banks of Loch Ness and has the capacity to generate 305MW. It is controlled remotely from SSE’s Renewable Operations Centre in Perth and can quickly respond to peaks in demand. If required, it can supply 300,000 kW of electricity within 30 seconds. The power station houses two 150MW sets located in separate 50.2m deep elliptical shafts.

Pumped storage schemes, like Foyers, involves two bodies of water at different heights. During period of low demand for power, electricity is used to pump water from the lower loch to the upper reservoir. The water is released to create energy at a time when demand is high.

Completed in 1975, the Foyers pumped storage scheme uses Loch Mhor Dam as its upper reservoir. Originally Loch Mhor Dam was built to provide a storage reservoir for the Falls of Foyers scheme, developed in 1896.

The scheme became the first hydro-electric powered aluminium smelter in the UK and by 1911 one third of the world’s aluminium was produced in the Highlands. Before the large scale development of hydro power in the highlands many homes did not have electricity, and hydro stations, including Foyers, helped to bring it to homes across the North of Scotland.

Loch Mhor Dam celebrated its 120th birthday in 2016 making it the oldest member of SSE’s Hydro assets.

Foyers fast facts

  • When Foyers is generating, water is allowed to flow through tunnels from Loch Mhor through two miles of tunnels and shafts to the power station.
  • When pumping, energy is drawn from the main transmission system at times of low load to drive two 150MW machines in reverse direction and pump water from Loch Ness up to Loch Mhor.
  • The power station houses the two 150MW machines in separate 50.2m deep elliptical shafts. The Scott monument in Edinburgh would easily be accommodated in one of these shafts.
  • When generating at full load, 200 cubic metres per second of water – or 200 tonnes per second – is passed into Loch Ness.