SSE’s Coire Glas Hydropower Project on Loch Lochy in Scotland has been awarded Gold certification under the Hydropower Sustainability Standard (HSS), becoming the first pumped storage project in the world to achieve this recognition.

This global milestone highlights the project’s strong sustainability performance at the preparation stage, and underscores the potential of pumped storage to support resilient, renewable-powered energy systems.

Coire Glas has also qualified for the IHA Blue Planet Prize 2025, awarded to the world’s most outstanding sustainable hydropower projects. Winners will be announced on 9 September at the International Forum on Pumped Storage Hydropower, taking place in Paris.

Eddie Rich, CEO of the International Hydropower Association (IHA), said: “Coire Glas is exactly the kind of project we need for our future energy systems, and this Gold certification highlights how SSE Renewables have planned it responsibly from the outset. The UK is helping lead the way in advancing policy frameworks to enable much-needed long-duration energy storage, and Coire Glas shows that it’s possible to meet this challenge while upholding the highest standards in sustainability.”

The proposed Coire Glas project would be the United Kingdom’s largest long-duration energy storage (LDES) facility if approved for delivery – subject to the development of a suitable government support mechanism – with the potential to store around 30GWh of renewable energy.  

A preparation stage assessment conducted earlier this year under the Hydropower Sustainability Standard found strong performance across key sustainability topics including labour and safety standards, governance, and stakeholder engagement. The project also demonstrated thoughtful planning for environmental and social outcomes, with high marks for its approach to water and sediment management, biodiversity, and cultural heritage.

João Costa, Executive Director of the Hydropower Sustainability Alliance, said: “Pumped storage is essential to a resilient, renewable-powered grid, and Coire Glas is showing that large-scale projects can be designed with sustainability built in from the beginning. It’s exciting to see the Hydropower Sustainability Standard being used to shape one of the UK’s most ambitious energy projects.”

Mike Seaton, Coire Glas Project Director, said: “Attaining Gold certification is a testament to the diligence and dedication of the Coire Glas project team. It also reflects the positive contribution of the contractors who worked with us on the project to date.  

“While there is still a way to go to ensure there is an investable policy mechanism to support it, Coire Glas has a crucial role to play in helping the UK and Scottish Governments meet their net zero targets. We are delighted to demonstrate that developments of this type can be developed with a focus on sustainability.”

Andrew Jacobs, SSE Hydro Sustainability Partner, added: “Working towards our certification with the Hydropower Sustainability Alliance has been a rewarding and challenging experience. Achieving Gold certification has enabled our development team to highlight how our world-class Coire Glas project can harness renewable energy sources in a way that can bring our sustainability commitment to life.

“We are grateful to the external stakeholders who supported us throughout the certification consultation process, and we look forward to building on these positive relationships as we progress the Coire Glas project.”  

Coire Glas is poised to play a key role in supporting climate resilience and helping the UK meet its net-zero goals.