Drax has announced its intention to build a new hydro power station inside a mountain, which will be housed within a cavern large enough to fit Big Ben on its side.
The energy group has applied for planning consent to build the new underground pumped-storage facility, which would more than double the electricity generating capacity at its ‘Hollow Mountain’ facility in Cruachan, Scotland.
The 600MW power station will increase the site’s total capacity to 1.04GW, and could be operational by the end of the decade.
Around two million tonnes of rock will have to be excavated to create the cavern, tunnels, and other parts of the power station.
The site will provide critical stability services to the power system by acting like a giant water battery, using reversible turbines to pump water from Loch Awe to the upper reservoir on the mountainside, to store excess power from wind farms and other low carbon technologies when supply outstrips demand.
Drax will then use this stored water to generate renewable power when it is needed.
Wind farms are routinely paid to turn off when supply outstrips demand or there is insufficient capacity on the National Grid Transmission System due to a lack of energy storage creating local bottlenecks.
In 2020, enough wind power to supply around a million homes went to waste because of this.
If approved, the infrastructure project will provide critical storage capacity to strengthen the UK’s energy security and support around 900 jobs, requiring six years of construction across the supply chain in a range of industries from quarrying and engineering, to transport and hospitality.
To build the plant, Drax must secure consent under Section 36 of the Electricity Act 1989 from the Scottish Government – a process which will take around one year to complete.
The plans will also require an updated policy and market support mechanism from the UK Government.
The existing lack of a framework for long-duration electricity storage and flexibility technologies means that private investment cannot currently be secured in new pumped storage hydro projects, with no new plants built anywhere in the UK since 1984.
No investment decision has yet been taken, and development remains subject to the right regulatory framework with the UK government.
Drax argues that the generation of pumped storage hydro plants can play a major role in reducing emissions and significantly cutting the UK’s reliance on imported gas through their storage and flexibility services.
Ian Kinnaird, Drax’s Scottish assets director, said: “Drax’s plan to expand Cruachan will strengthen the UK’s energy security by enabling more homegrown renewable electricity to come online to power homes and businesses across the country, helping to end our reliance on imports and cut costs.”
Claire Mack, Scottish Renewables chief executive, added: “Pumped storage hydro is a critical technology needed to meet net zero. Over the last decade we have managed to develop the technologies to decarbonise the power system such as wind and solar, but what we really need now is greater flexibility to fully optimise those technologies. That’s why the success of long-duration storage projects such as Cruachan 2 is absolutely vital to Scotland and the whole of the UK.”