UK approves largest pumped hydro scheme

April 07, 2025

The Scottish Government’s Energy Consents Unit has granted planning permission to Kendal-based Gilkes Energy for a 1.8 GW/40 GWh pumped hydro energy storage project at Loch Earba in the Scottish Highlands. Located about 124 miles from Glasgow, the project is set to be the largest of its kind in the UK.

The Earba Pumped Storage Hydro project, near the Cairngorms National Park, is set to operate by transferring water between Loch Earba and an upper reservoir, Loch Leamhain. The project’s upper reservoir, when full, will store enough energy to generate 22 hours of electricity at its full 1.8 GW capacity, supplying power to over 1.4 million households annually.

Power for 1.4 million households each year

The proposed site work will involve constructing dams to raise the water levels of both lochs, connected by an underground waterway system with up to three headrace tunnels. Key elements of the project include building a powerhouse, an indoor electrical switchyard, two aqueducts, a new road junction, and a bridge over the River Spean, which flows near the site.

According to Gilkes Energy’s managing director Carl Crompton, the real work for the company “begins now” as it transitions from a consented project to a fully designed, tendered, and costed venture. The application also includes proposals for two large-scale peatland and woodland restoration projects.

“As the UK energy system shifts from being dominated by dispatchable thermal generation to one driven by intermittent renewables, the need for energy storage is increasing significantly. Storage systems enable excess renewable energy, primarily from wind, to be stored and used later during periods of low renewable generation,” Crompton said in a statement.

The next steps now involve securing substantial capital required to bring the project to life and ensure it is viable financially. David Tomb, Earba’s project director, highlighted that it has been over 50 years since the last UK pumped hydro storage project began, making it vital to collaborate with suppliers to develop the necessary supply chain capacity for a project of this scale.

Project to support 500 jobs in six-year build phase

The UK-based company expects the project to create 500 on-site jobs during the six-to-seven-year construction period, spanning various roles in construction, engineering, and project management.

Crompton also emphasized that energy storage plays a crucial role in integrating more renewables into the UK energy system, advancing the country’s progress toward Net Zero while strengthening energy security. 

The company highlighted that Long Duration Energy Storage (LDES) provides significant benefits, including reducing wind curtailment costs—costs that are typically passed on to consumers—and decreasing reliance on costly gas generation.

Following the approval of Earba, Gilkes Energy has submitted a planning application for another major LDES project in collaboration with Perth-based SSE Renewables. The two companies are seeking consent to build a 1.8 GW/36 GWh pumped hydro energy storage project in Scotland.

“We are also working closely with the UK Government and Ofgem to implement the Long Duration Energy Storage (LDES) ‘Cap & Floor’ mechanism in 2025. This investment framework acknowledges the importance of pumped storage hydro while addressing the challenges of financing such capital-intensive, long-lead-time projects.” Crompton added.