Coire Glas in the Scottish Highlands could power three million homes

SSE and Drax are among a number of companies with plans to flood Scottish glens and hollow out mountains to build up to six pumped storage hydro-electric stations.

The companies say the £8 billion investment in clean energy would increase the UK’s existing hydro infrastructure threefold and create up to 15,000 jobs.

They are lobbying the government for financial support on the back of report by Scottish Renewables and BiGGAR Economics into the potential economic benefits of the projects.

Despite the growing need for storage as Britain builds more intermittent wind and solar power, no new projects have been commissioned since 1984.

Andrew MacNish Porter of Scottish Renewables said: “We urgently need the government to clarify its support for pumped storage hydro and deliver the required policy support to unlock the huge value these projects promise to deliver.”

If approved, SSE’s Coire Glas project will create a reservoir containing the equivalent of 11,000 Olympic-sized swimming pools, 500 metres above Loch Lochy in the Highlands. It will use water from the Great Glen to power three million homes.

Drax wants to expand its Cruachan “hollow mountain” plant at Loch Awe in Argyll and Bute with additional waterways between the upper and lower reservoirs and new caverns to house more turbines.

Intelligent Land Investments is proposing three projects involving creating new upper reservoirs, damming valleys above Loch Ericht in Perth & Kinross and Loch Awe, and creating a new upper reservoir from scratch above Loch Ness in the Highlands.

Buccleuch Estates and Foresight want to use a disused open-cast coal mine at Glenmuckloch in Dumfries & Galloway into a lower reservoir and construct a new upper reservoir nearby.