SSE takes final investment decision on 100MW Derrymeen Battery Energy Storage System

SSE’s 50MW battery storage asset at Salisbury in Wiltshire, England, which entered commercial operation in April 2024. Picture credit SSE Renewables. 

SSE has announced that it has taken a Final Investment Decision to begin construction on a new 100MW Battery Energy Storage System (BESS) in County Tyrone.

Delivery of the new battery storage facility will support Northern Ireland’s transition to a renewables-led electricity system. Located beside the Tamnamore 275/110kV substation, near Dungannon, the Derrymeen BESS facility will provide 100MW of capacity with two hours of storage, equivalent to 200MWh. The facility will connect to the substation and will participate in the all-island Integrated Single Electricity Market (SEM).

Once operational, it will help balance the grid and support security of supply by storing electricity when generation is high and releasing it back to the system when demand increases. The project will strengthen Northern Ireland’s electricity network by providing flexible storage capacity to support renewable generation and enhance security of supply.

Construction will follow later in 2026, after the conclusion of early activities, including detailed design and procurement of key equipment such as the main grid transformer, which are already underway.

Grid connection works will be carried out in coordination with the System Operator for Northern Ireland (SONI) and Northern Ireland Electricity Networks (NIE).

Delivery of the project will also create employment opportunities during construction and support local businesses through engagement with regional contractors and suppliers. At peak delivery, the project is expected to support up to 30 full-time jobs.

Heather Donald, Director of Projects Onshore Ireland at SSE Renewables, said: “Securing a final investment decision for Derrymeen marks another important milestone in our commitment to building a flexible and resilient energy system across the island of Ireland.

“Battery storage is essential to enabling a renewables-led electricity system, helping to store clean power when it is available and deliver it back to the grid when it is needed most. We are proud to be investing in Northern Ireland’s energy future, working closely with our partners and stakeholders to deliver a project that supports security of supply and the energy transition.”

Following design refinements and engagement with local council, the project has now progressed to final investment decision. The project has also secured a 10-year Capacity Remuneration Market (CRM) contract beginning in October 2028.