Global hydro experts appointed to enhance Cruachan expansion design

Renewable energy leader Drax has appointed globally renowned hydro engineering consultants Studio Pietrangeli to optimise its plans to build the UK’s first new pumped storage hydro plant in almost 40 years.

Drax is progressing plans to build a new 600 MW underground plant adjacent to its existing underground Cruachan facility in Argyll, Scotland. Increasing the UK’s pumped storage hydro capacity is critical to enabling more wind and solar power to come online, strengthening the country’s energy security while helping Britain decarbonise.

Studio Pietrangeli will act as Owner’s Engineer on the project, supporting key activities including optimising the detailed design and layout of the new plant, providing expertise around the major civil engineering components of the project, such the excavation and tunnelling of rock within Ben Cruachan and preparing the specifications for a Front End Engineering and Design study. This will ensure that Cruachan 2, once constructed, is one of the most modern and efficient pumped storage plants in Europe.

Ian Kinnaird, Drax’s Scottish Assets Director, said:

“This is a significant moment in Drax’s planned expansion of Cruachan.

“The scale of the proposed development matches Drax’s ambitions when it comes to tackling the climate crisis. More than 2 million tonnes of rock will be excavated to create a new cavern inside the mountain which will be big enough to house Big Ben on its side.

“Pumped storage hydro is vital to strengthening the UK’s energy security by enabling more homegrown renewable electricity to come online, cutting the need to import power or fossil fuels from abroad. This will be a major infrastructure project which will support hundreds of jobs and provide a real boost to Scotland’s economy.”

Antonio Pietrangeli, Managing Partner of the firm and Project Director for this assignment said:

“SP is delighted to have been appointed as Owner’s Engineer to assist Drax in developing this important pumped storage plant. Pumped storage is becoming increasingly valuable in facilitating countries’ efforts to meet their carbon-reduction goals and reduce dependence on fossil fuels. The Cruachan 2 plant will be a crucial step towards the UK’s achievement of these goals.”

Pumped storage hydro plants act like giant water batteries, using reversible turbines to pump water from a lower reservoir to an upper reservoir which stores excess power from wind farms and other low carbon technologies when supply outstrips demand. These same turbines are then reversed to bring the stored water back through the plant to generate power when it is needed.

In order to deploy this critical technology, Drax must secure consent from the Scottish Government alongside an updated policy and market support mechanism from the UK Government.

The existing lack of an appropriate framework for new long-duration, large-scale electricity storage 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 despite their critical role in security of supply and decarbonisation.


Media contacts:

Aidan Kerr
Media Manager
E: [email protected]
T: 07849090368

Editor’s Notes

  • Studio Pietrangeli will provide Drax with expertise across a range of services, including: Civil & Structural Engineering, Mechanical Engineering, Electrical Design, Process Design, Process Safety, Control & Instrumentation, Health, Safety & Environmental Services, Quality Assurance, Commercial Support, and other Specialist Services.
  • Drax applied for development consent from the Scottish Government under Section 36 of the Electricity Act 1989 in May 2022.
  • We expect a response to the application to be received in Q2 or Q3 2023.
  • BEIS has pledged to introduce a new policy and market support framework to enable private investment in large-scale, long-duration storage projects by 2024.
  • No investment decision has yet been taken by Drax and development remains subject to both development consent and an appropriate regulatory framework.


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.

Drax’s around 3,000 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. For more information visit

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.

The Group also aims to build on its BECCS innovation at Drax Power Station with a target to deliver 4 million tonnes of negative CO2 emissions each year from new-build BECCS outside of the UK by 2030 and is currently developing models for North American and European markets.

Pellet production and supply:

The Group has 18 operational pellet plants and developments with nameplate production capacity of around 5 million tonnes a year.

Drax is targeting 8 million tonnes of production capacity by 2030, which will require the development of over 3 million tonnes of new biomass pellet production capacity. 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 plants supply biomass used at its own power station in North Yorkshire, England to generate flexible, renewable power for the UK’s homes and businesses, and also to customers in Europe and Asia.


Drax supplies renewable electricity to UK businesses, offering a range of energy-related services including energy optimisation, as well as electric vehicle strategy and management.

To find out more go to the website