Under the partnership, Wärtsilä recently completed the fifth and sixth grid-scale battery energy storage projects and signed additional long-term service agreements to ensure performance and reliability across all systems.
"Battery energy storage has a huge role to play in enabling the UK’s clean energy transition. This vital technology helps make the most of electricity generated by renewables, like wind and solar, while also improving grid reliability. Our partnership with Wärtsilä helps us to optimize our grid-scale projects,” says Simone Sullivan, Head of Storage, EDF Renewables.
To date, six out of eight facilities are operational. The projects that recently reached completion include the 50 MW / 100 MWh Sundon project in Bedfordshire, which began commercial operations in December 2024, followed by the 57 MW / 114 MWh Bramford project, located in Suffolk, in April 2025.
The two additional projects—Indian Queens in Cornwall and Bredbury in Greater Manchester—are currently under construction. Bredbury (50 MW / 100 MWh) is scheduled for completion by late 2025 and Indian Queens (47.5 MW / 95 MWh) is expected to come online in the first half of 2026.
All eight projects are covered by Wärtsilä’s long-term service agreements, providing EDF Renewables with increased operational efficiency and cost predictability. The long-term service agreements for the Sundon, Bramford, Indian Queens, and Bredbury projects guarantee performance levels, backed by a dedicated support team.
“Together with EDF Renewables, we are enhancing the reliability and flexibility of the UK’s energy system—delivering tangible progress toward a 100% renewable energy future. Our long-term service agreements further reinforce this commitment by ensuring performance, minimising operational risks, and maximising lifecycle value,” says Chris Wolf, Sales Director for Europe at Wärtsilä Energy Storage.
Alongside Wärtsilä’s battery energy storage systems, all eight sites are managed by Wärtsilä‘s controls and optimisation software, GEMS. GEMS provides EDF Renewables with data-driven insights for comprehensive asset management, performance optimisation, and market trading. It also enables EDF to maximise revenue opportunities through grid services such as electricity market trading and frequency response, while simultaneously bolstering grid stability.
Wärtsilä’s total portfolio with EDF Renewables includes:
