Hydroelectric power Scotland


Duration:82 years and counting


Country: Scotland, UK

What did this project achieve?

Use water to create a sustainable and affordable energy supply for Scotland

Scotland has the UK's highest mountains and largest inland lochs (lakes). Combined with a high rainfall this makes production of hydroelectricity viable in the region.

Hydroelectric generation in Scotland started early in the 20th century – kickstarted by the need for power to drive aluminium smelting plants at Kinlochleven and Lochaber in the Highlands. This led to the construction of the Laggan dam and hydroelectric system in 1934.

Scotland now has 85% of the UK's hydroelectric energy resource, much of it developed in the 1950s by the North of Scotland HydroElectric Board. The board played a large part in bringing 'power from the glens' into Scottish homes.

By 1965, 54 main power stations and 78 dams had been built, providing a total generating capacity of over 1,000MW.

Hydroelectric schemes are still being built in Scotland. Small projects powering maybe 200 homes have become popular with an increase in government subsidies.

Difference hydroelectricity has made

In the 1940s it was estimated that just 1 farm in 6 and 1 croft in 100 had electricity in Scotland. Today almost every home in Scotland has mains electricity.

Without hydroelectricity it would have been prohibitively expensive to get mains electricity to a widespread population and virtually impossible in some remote areas.

Tapping into 'power from the glens' has made electricity affordable and sustainable, especially for remote areas of the country.

Around 12% of Scotland's total electricity now comes from hydroelectric generation.

How the work was done

The Laggan dam was built in 1934. At 700ft (210m) long and 157ft (48m) high it was one of the first major hydroelectric schemes in Scotland.

Apart from a middle section – housing equipment – the whole dam is a spillway. This is a structure engineers use to provide the controlled release of water flows into a downstream area.

The dam is built on granite. Engineers constructed it in 7 sections using copper strip and hot poured asphalt to seal the joints.

Engineers laid 3 miles (4.8km) of tunnel 15ft (4.6m) in diameter to carry water from the dam to Loch Treig. From there the water travels downhill through another 15 miles (24km) of pipe to a power station at Fort William.

Other major hydroelectric sources in Scotland include the Tummel valley. The first power stations were built in the valley in the 1930s.

Engineers saw that the valley's combination of steep gradients and melting snow from the Grampian mountains was ideal for producing hydroelectricity.


The power of Scotland's water… is just amazing.

Mike Cantlay

Convenor, Loch Lomond National Park. The park has more than 50 rivers – ideal for smaller hydropower projects

Fascinating facts

The 54 power stations and 74 dams built in Scotland by 1965 saw 300km of rock tunnel excavated.

More than 32,000km of electricity network was built to distribute power across the north of the country. A further 110km of submarine cable took electricity to the Scottish islands.

Up to 12,000 workers helped to build the power stations and dams. Some of these were former German and Italian prisoners of war.

People who made it happen

  • Builders: Balfour Beatty
  • Supervising engineers: CS Meik and William Halcrow (now the Halcrow Group)
  • George Balfour (Balfour Beatty chairman) oversaw construction

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