Coire Glas, Britain's biggest natural battery, can deliver for net zero and energy security.

We want to invest more than £1.5bn to build what will be Britain’s biggest natural battery, helping deliver net zero and energy security for the UK. Our Coire Glas pumped hydro storage project on the shores of Loch Lochy in the heart of the Scottish Highlands would help maintain supplies of clean, secure and flexible renewable energy even when the wind isn’t blowing and the sun isn’t shining.

If approved for construction, the Coire Glas project would be the largest engineering project in the Highlands, creating up to 500 full time construction jobs at peak and injecting millions of pounds in direct supply chain support into the Scottish and UK economies.

Once operational, it would double the country’s current flexible electricity storage capacity^ and could power 3 million homes for up to 24 hours.

So, what are we waiting for?

All we need is one simple policy decision from the UK Government.

What action is needed now?

SSE stands ready to unlock investment of over £1.5bn in our Coire Glas project, which could play a crucial role in supporting Britain’s long term energy security and in meeting net zero.

What we need however is one simple policy decision from the UK Government which will send a clear signal to infrastructure investors such as SSE as to how Government intends to support the deployment of long-duration electricity storage, as set out in last year’s ‘British Energy Security Strategy’.

Extraordinary flexibility with massive storage potential

Coire Glas could deliver an extraordinary level of flexibility to the UK's energy system and support a larger penetration of wind and solar energy onto the national grid due to its massive 30GWh storage potential, making it potentially Britain's biggest natural battery.

Coire Glas could use the energy stored within to function in a variety of ways. It can be used to run at full maximum load for over 24 hours; or run day after day through the evening peak hours. At the same time, it could run for just minutes - going from zero output to full output within five minutes. This makes Coire Glas a genuinely renewable decarbonised form of flexibility that enables the grid to support more and more wind and solar to displace oil and gas provision.

SSE’s ability to reach a positive final investment decision on the £1.5bn+ project depends on the UK's prevailing policy environment for long duration electricity storage and long-term infrastructure projects more broadly, as well as positive development progress on the project. If approved for delivery, Coire Glas could be operational by 2031.

One simple policy decision is all we need

At SSE we're calling on the UK Government to provide one simple policy decision that will send a clear signal as to how Government intends to support the deployment of long-duration electricity storage.

Coire Glas doesn’t need a subsidy but it would benefit from revenue stabilisation, and clarity on such support sooner rather later.

That’s why it’s critically important the UK Government urgently confirms its intention on exactly how it will help facilitate the deployment of pumped hydro storage projects as part of Britain's future energy mix.

“We have a clear government target to have a decarbonised net zero power system by 2035. Pumped hydro storage has massive potential to enable that. But these are large, complex projects. If Coire Glas is going to play its part, we need to reach a final investment decision in the next couple of years, and it needs to be being built in the 2020s.”

Finlay McCutcheon - Director of Onshore Renewables

"Hydro power was Scotland’s original source of renewable energy and has the potential to play a significantly greater role in the transition to net zero. We will continue to call for the UK government to provide an appropriate market mechanism for hydro power and other long duration energy storage technologies, to ensure this potential is fully realised." Humza Yousaf, First Minister of Scotland

For more about Coire Glas, the country’s most advanced flexible energy storage project currently in development, please download our briefing document.

Click here

^ Coire Glas is the country’s most advanced, flexible energy storage project currently in development and if built, would deliver up to 30GWhs of flexible electricity storage. As the only new project currently in development which is fully consented, it would become Britain’s biggest natural battery.

Great Britain’s current flexible electricity storage capacity is verified externally in the ‘Future Energy Scenarios’ publication by National Grid in July 2022, which examined electricity storage in Great Britain. This report demonstrates that at the end of 2021, there was less than 30GWh of electricity storage capacity in Great Britain, of which 94% is from pumped hydro storage (25.8GWh), with around 6% from other forms like batteries (1.6GWh).