The Friends of Loch Lomond and The Trossachs has welcomed progress on SSE Renewables’ plans to convert the Sloy Power Station near Tarbet into a pumped storage facility.
The charity confirmed that the project has cleared a key stage in the Loch Lomond and The Trossachs National Park Authority’s planning process.
Tarbet resident and charity trustee Duncan MacLachlan said: “We’re very pleased to see that the plans to redevelop the Sloy Power Station as a Pumped Storage facility have gone through the National Park’s planning processes successfully. The Section 36 category of the application has still to be assessed, but we are confident the Scottish Government will give approval, especially considering the valuable contribution the project will make to the country’s capacity to store surplus renewable solar and wind energy, providing stability for the national power distribution grid and boosting energy security. As well as enhancing the status of Sloy Power Station’s iconic Modernist Classical building, it should also bring some much-needed economic benefit for the local community.”
SSE Renewables submitted the application in April 2025. If approved, the converted facility would provide up to 16GWh of long-duration storage capacity, capable of delivering renewable electricity for up to 100 hours non-stop. The company says the scheme would improve energy security and support the UK Government’s goal of a net zero power system by 2030.
Sloy Power Station, opened in 1950, is the UK’s largest conventional hydroelectric plant. It uses water from Loch Sloy, carried through a tunnel in Ben Vorlich before descending pipelines to the station at Inveruglas Bay on Loch Lomond. It generates around 130 million units of electricity annually in an average rainfall year.
A handling report from a National Park planning officer said the new pump hall would operate underground, separate from the listed Sloy Power Station building. A new glass and stone structure would be built above ground to the northeast, housing electrical equipment and pump infrastructure.
The new building would be slightly lower than the main power station and designed to echo its style, with tall glazed sections and simple columns. Officials said it would not dominate or block views of the original building.
The report concluded that while the development would change the setting of the site, the impact would be limited and offset by the quality of the design and landscaping. Plans also include woodland management to remove non-native trees and replant with native species.
Overall, the officer said the project would preserve the character and architectural value of the listed power station and fit sensitively into the landscape.
