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Pumped hydro scheme could more than double Britain’s electricity storage capacity

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The Coire Glas pumped hydro scheme in the Scottish Highlands, able to more than double Britain’s electricity storage capacity, has received a £100m investment from its’ owners SSE Renewables.

The project, which if approved will be the country’s first pumped hydro scheme in 40 years and the largest engineering projects in the Scottish highlands since 1943, is expected to cost £1.5 billion to construct. It will be located on Loch Locky, between Fort William and Inverness and received planning consent from the Scottish Government in 2020. SSE hope to commission the pumped storage scheme by 2031.

Once complete, Coire Glas would be able to deliver 30GWh of long duration storage and generate enough renewable energy to power roughly 3 million homes in just under 5 minutes. The scheme would take excess energy from the grid and use it to pump water 500 meters up a hill from Loch Lochy to a vast upper reservoir equivalent to nearly 11,000 Olympic-sized swimming pools where it would be stored before being released to power the grid when wind output is low and customer demand is high.

A computer generated image (CGI) of the turbne hall at the Coire Glas pumped hydro scheme
A computer generated image (CGI) of the turbne hall at the Coire Glas pumped hydro scheme

The project’s delivery will be heavily infuenced by the UK Government’s decision on how it intends to financially support the deployment of long-duration electricity storage, as set out in last year’s Energy Security Strategy, which could include the introduction of a ‘revenue stabilisation mechanism’ in the form of an adapted Cap and Floor scheme to support investment in long-duration storage.

Scotland’s Cabinet Secretary for Net Zero, Michael Matheson, who visited SSE’s Pitlochry Dam and Hydro Station today, said:

“Today’s announcement is a significant and important milestone on the journey towards delivering the Coire Glas project. If built, Coire Glas will more than double Britain’s long duration electricity storage capacity – allowing the grid to more flexibly deploy renewable electricity. The Scottish Government has long been supportive of pumped hydro storage capacity, which we believe will play a key role in the energy transition and is a vital component of a more flexible, resilient and secure electricity supply.

“However it is critical that the UK Government puts in place the appropriate market and regulatory arrangements to support the industry’s development as a matter of urgency. Only with a supportive policy environment can this sector realise its full potential.”

Gregor Alexander, SSE’s Finance Director, said:

“Coire Glas will be one of the most ambitious energy infrastructure projects the UK has ever seen and is a key component of SSE’s commitment to helping lead Scotland and the UKs’ energy transition.

“Our investment commitment today signals a significant down-payment by SSE to keep this critical project moving forwards. And our ability to reach a positive final investment decision will clearly depend on the prevailing policy environment for long duration electricity storage and long-term infrastructure projects more broadly. If delivered around the turn of the decade, Coire Glas could play a crucial role in getting the UK to net zero.

“Whilst Coire Glas doesn’t need subsidy, it does require more certainty around its revenues and it is critically important the UK Government urgently confirms its intention on exactly how they will help facilitate the deployment of such projects”


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