Scotland's hydropower heritage - The role of Scottish hydropower

Scotland is also a world leader in the development and deployment of wave and tidal energy technologies. It hosts: the world’s leading wave and tidal test centre, the European Marine Energy Centre (EMEC) in Orkney; the world’s largest tidal stream array; and, the world’s most powerful tidal stream turbine.

Over the last century, Scottish hydropower played a major part in the country’s energy make up. While today hydro lags behind wind and solar as a source of renewable electricity in the UK, it played a vital role in connecting vast areas of rural Scotland to the grid, some of which had no electricity as late as the 1960s. Soon, new pumped-storage schemes will integrate perfectly with the increasing use of intermittent renewables.

History and milestones

At the end of the 19th century, Scotland’s first known hydro scheme was built on the shores of Loch Ness at the Fort Augustus Benedictine abbey. The scheme provided power to the monks, as well as to 800 village residents.

The huge potential of Scotland’s steep mountains, lochs and reliably heavy rainfall, to generate substantial amounts of hydropower, was first recognized in the 1890s. A reliable source of electricity was needed to help turn raw bauxite into aluminium, and the Foyers hydro plant and smelting works were built in 1896.

But it was more than 20 years before the first major hydro project to supply electricity to the public was designed. In 1926 the Lanark hydro scheme was commissioned on the river Clyde. It is still in operation, with a capacity of 17 MW today. This was followed by plants at Rannoch and Tummel in the Grampian mountains and, in 1935, what became a highly influential cascade scheme in the history of Scottish hydropower, at Galloway.

Scotland’s first major pumped-storage plant was Cruachan, in Argyll, inaugurated by Queen Elizabeth II in 1965; the final unit was commissioned in 1967. This was the largest plant of its type in the world at that time. A major expansion project at the 440 MW plant is planned, which will add a new 600 MW underground plant.

The most recent large hydro plant to be commissioned in Scotland was the 100 MW Glendoe scheme, in the Highlands above Loch Ness; it was commissioned in 2009. More recently, in 2021, RWE commissioned the 2 MW Glen Noe run-of-river small scheme.

Into the future

The next major development will be the implementation of several large pumped-storage plants. In 2021, the Scottish Government granted planning consent for the 450 MW Red John scheme, which will be built close to Inverness; The Tongland upgrade in Dumfries and Galloway; Eishken (300 MW), using seawater, on the Isle of Lewis; Coire Glas in Lochaber in the Highlands, with a capacity of up to 1500 MW; Balliemeanoch (1500 MW); and, Corrievarkie (600 MW).

Scottish and other UK hydropower and dam engineers have much experience to share, as well as future plans to discuss.