Cruachan Expansion Project
Affectionately known as ‘The Hollow Mountain’, Drax’s Cruachan Power Station sits on the northern shores of Loch Awe, in Scotland. It is one of just four pumped storage hydro power stations in the UK.
Cruachan’s design enables it to store excess renewable power from sources such as wind farms. When the wind isn’t blowing, the plant then uses this stored power to plug gaps in supplies – making it a critical component of the UK’s national energy security.
Drax believes Cruachan can play an even bigger role in the fight against climate change, enabling the UK to reach its goal of having a clean power grid by 2030.
What is the Cruachan Expansion project?
We’re progressing plans to build a second underground pumped storage hydro plant at Cruachan. It will more than double the site’s generating capacity, allowing it to generate enough power for around two million homes.
The 600-megawatt (MW) power station will be located inside Ben Cruachan – Argyll’s highest mountain – and increase the site’s total capacity to more than 1 gigawatt (GW)
The new power station would be built within a new, hollowed-out cavern which would be large enough to fit Big Ben on its side, to the east of Drax’s existing 440MW pumped storage hydro station.
More than two million tonnes of rock and soil would be excavated to create the cavern and other parts of the power station. The existing upper reservoir, which can hold 2.4 billion gallons of water, has the capacity to serve both power stations.
Cruachan’s upper reservoir is Scotland’s largest battery, with a storage capacity equivalent to around 145,000 fully charged Tesla model 3s.
What will the project deliver?
In addition to strengthening the country’s energy security, the Cruachan Expansion Project will deliver jobs and economic benefit for Scotland and the whole of the UK.
During its construction phase, the expansion is projected to support over 150 jobs in Argyll and Bute and over 500 jobs across the wider supply chain in Scotland. In total it will support 1,100 jobs across the UK.
Expanding Cruachan will boost the Scottish economy, with a benefit of up to £260m GVA during construction. In Argyll and Bute, this equates to up to £73m GVA added to the region’s economy. Across the UK, this is a total possible benefit of over £470m GVA.
The project will result in one of the biggest pumped storage hydro plants in the UK, helping to achieve its Net Zero targets.
Cruachan's future
Drax was granted development consent for the Cruachan Expansion Project from the devolved Scottish Government in July 2023.
No new pumped storage hydro plants have been constructed in the UK since 1984, despite their critical role in enabling decarbonisation of the power grid. One of the main reasons behind this anomaly is the lack of a suitable business model within the UK energy policy landscape.
In January 2024, the UK Government confirmed it believes a Cap and Floor regime should be introduced to de-risk private investment in new long-duration electricity storage projects such as the Cruachan Expansion Project.
Drax, alongside the wider industry, is now working in partnership with the government to ensure a suitable business model is introduced to enable projects to move forward.
In addition to the Expansion, Drax has begun an £80 million upgrade of the existing Cruachan Power Station.
