Renewable energy leader Drax has announced the appointment of global technology and engineering firm Voith Hydro to move forward its 'Hollow Mountain' plans – the UK's first pumped storage hydro scheme in 40 years.

The proposed 600 MW underground plant would be constructed underground adjacent to Drax's existing Cruachan facility near Oban in Scotland.

Exploratory ground works are currently underway at the site, with seismic surveys being undertaken to provide crucial geological data about the rock in which the new plant would be housed inside.

As part of its development of the project, Drax has appointed Voith Hydro to complete a Front-End Engineering and Design (FEED) study for the Mechanical and Electrical components of the design. This work will produce a series of comprehensive reports, data and models that will provide a well-defined project scope, design, cost estimate, and schedule, enabling informed decision-making and reducing uncertainties before proceeding to the detailed engineering, procurement, and construction phases.

This is a major milestone as Drax harnesses Voith's expertise and engineering technology to progress and optimise the design of the new Cruachan power station.


Drax's proposals received development consent from the Scottish Government last year, but the project's continued progression requires an updated policy and market support mechanism from the UK Government. Despite their critical role in decarbonisation, no new pumped storage hydro plants have been constructed in the UK since 1984 due to the current lack of a suitable framework. Earlier this year, the UK Government launched a consultation on its plans to introduce a new framework which could unlock billions of pounds worth of private investment in the technology.

Steve Marshall, Drax's Development Manager, said: "A new generation of pumped storage hydro plants will strengthen the UK's energy security by enabling more homegrown renewable electricity to come online to power homes and businesses across the country. Drax's plan to build a new plant at Cruachan will support hundreds of jobs and provide a real boost to the Scottish economy

"With the project granted development consent from the Scottish Government, we hope the next UK Government will continue policy development in this area at pace to enable a new generation of pumped storage plants to come online as possible.

Stefan Linhart, Project Manager at Voith Hydro, said: "We at Voith Hydro are highly committed to the Cruachan 2 project and feel honoured to have been nominated by Drax for the Front-End Engineering Design (FEED). As a full-line supplier for hydropower technology we are looking forward to bringing our extensive experience in the field of pumped storage.

"The constructive and professional collaboration with Drax and other project partners is key to achieve our common goal: a power plant that meets the latest standards in performance and safety."

Increasing the country's pumped storage hydro capacity is critical to enabling more renewable power to come online, strengthening the country's energy security whilst helping the UK to decarbonise.

In addition to its plans to build a new power station, Drax is currently completing an £80 million upgrade to the existing plant. The project will see the generating capacity of two of the plant's four units increased by a combined 40 MWs to raise the facility's total generating capacity to 480 MWs.