Scottish Net Zero Minister visits iconic ‘Hollow Mountain’ Cruachan Power Station

January 12, 2022

The Scottish Government’s Cabinet Secretary for Net Zero, Energy and Transport, Michael Matheson, has visited Drax Group’s iconic ‘Hollow Mountain’ Cruachan Power Station to understand the critical role the facility will play in supporting Scotland’s net zero power system.

Cruachan is an underground pumped hydro storage power station built in a hollowed-out cavern 1km inside Ben Cruachan – Argyll’s highest mountain. Constructed in 1965, its reversible turbines are still at the cutting edge of energy storage technology, enabling the plant to act like a giant water battery.

Its turbines pump water from Loch Awe to an upper reservoir on the mountainside to store excess power from the grid. The stored water is then released back through the turbines to generate power quickly and reliably when demand increases. This process helps stop wind farms being paid to turn off when they are generating excess power, helping Scotland to be greener whilst cutting household energy bills.

Enough wind power to supply a million homes went to waste in the UK in 2020 because there wasn’t enough capacity to ensure this excess renewable power was stored and made available when it was needed.

As part of the visit, Drax Group’s Head of Hydro, Mike Wynd, also outlined the company’s exciting work on plans to build a new second underground pumped hydro storage power station at the Cruachan complex.


Drax Group’s Head of Hydro, Mike Wynd, said:


“Cruachan plays a critical role in stabilising the electricity system, balancing supply and demand by storing excess power from the national grid. When Scotland’s wind turbines are generating more power than we need, Cruachan steps in to store the renewable electricity so it doesn’t go to waste.

“Drax has exciting plans to more than double Cruachan’s generating capacity, a project that will support new green jobs and help our homes and businesses go greener by bringing more renewable power onto the grid.”


Cabinet Secretary for Net Zero, Energy and Transport, Michael Matheson MSP, said:


“It was fascinating to learn more about how important this unique power station is in supporting the Scottish energy system and the critical role it plays in keeping the power grid safe and stable.

“This kind of flexibility and resilience helps to support the growth of renewables, enabling further decarbonisation of the energy system as we strive for net zero carbon emissions in Scotland by 2045.”


Drax acquired Cruachan alongside the Galloway and Lanark hydro schemes in 2019, helping to make the company a leading provider of flexible, renewable power generation.

When all four of its generating units are operating at maximum capacity, the plant can supply enough flexible power for around 800,000 homes.


Media contacts:

Aidan Kerr
Drax Group Media Manager
T: 07849090368

Editor’s Notes

  • Pumped hydro storage power stations act like giant water batteries, storing excess energy when there is an oversupply of power and then releasing when the country needs it most.
  • This is especially useful in supporting wind and solar generation, storing excess renewable power to be used later instead of going to waste.
  • A recent report by the Renewable Energy Association (REA) highlighted the policy barriers to deploying long-duration energy storage and suggested ways to address these barriers such as through the introduction of an income floor.
  • Despite being a key supporting pillar for intermittent generation from wind and solar power, no new pumped storage plants have been built in Britain since 1984.
  • Drax has begun the planning process to build a new underground pumped hydro storage power station at Cruachan which will more than double the site’s electricity generating capacity.
  • The 600-megawatt (MW) power station will be located inside Ben Cruachan – Argyll’s highest mountain – and increase the site’s total capacity to 1 gigawatt (GW).
  • No final investment decision has yet been taken and development remains subject to the right regulatory framework with the UK government.

About Drax

Drax Group’s purpose is to enable a zero carbon, lower cost energy future and in 2019 announced a world-leading ambition to be carbon negative by 2030, using Bioenergy with Carbon Capture and Storage (BECCS) technology.

Its 3,400 employees operate across three principal areas of activity – electricity generation, electricity sales to business customers and compressed wood pellet production and supply to third parties.

Power generation:

Drax owns and operates a portfolio of renewable electricity generation assets in England and Scotland. The assets include the UK’s largest power station, based at Selby, North Yorkshire, which supplies five percent of the country’s electricity needs.

Having converted Drax Power Station to use sustainable biomass instead of coal it has become the UK’s biggest renewable power generator and the largest decarbonisation project in Europe. It is also where Drax is piloting the groundbreaking negative emissions technology BECCS within its CCUS (Carbon Capture Utilisation and Storage) Incubation Area.

Its pumped storage, hydro and energy from waste assets in Scotland include Cruachan Power Station – a flexible pumped storage facility within the hollowed-out mountain Ben Cruachan.

Pellet production and supply:

Drax owns and has interests in 17 pellet mills in the US South and Western Canada which have the capacity to manufacture 4.9 million tonnes of compressed wood pellets (biomass) a year. The pellets are produced using materials sourced from sustainably managed working forests and are supplied to third party customers in Europe and Asia for the generation of renewable power.

Drax’s pellet mills supply around 30% of the biomass used at its own power station in North Yorkshire, England to generate flexible, renewable power for the UK’s homes and businesses.


Through its two B2B energy supply brands, Haven Power and Opus Energy, Drax supplies energy to 250,000 businesses across Britain.

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