SSE wins Irish planning consent to double BESS duration to 320 MWh

Scottish-headquartered energy company SSE has secured planning consent from Mayo County Council for revised plans at its proposed 80 MW / 320 MWh Mullafarry battery energy storage system (BESS) near Killala, North Mayo, in Ireland, in the north-west.

Located at Killala Business Park, the Mullafarry BESS is adjacent to SSE’s 104 MW Tawnaghmore Power Station. Originally, in an April 2025 approval, the project plan was for an 80 MW / 160 MWh, 38-unit battery storage facility. Following updated planning consent, the project has now been increased to up to 64 battery storage units and a four-hour duration system with the same peak power output.

“We welcome Mayo County Council’s decision to approve our revised plans for the proposed Mullafarry battery energy storage system. This decision gives SSE the potential to significantly increase the energy output we can deliver through the project,” said Ghislain Demeuldre, head of onshore wind, solar and battery development at SSE Renewables.

The approval means the project still requires a final investment decision by SSE, and if approved for investment, an estimated two-year construction phase would begin.

“By storing electricity when supplies are high and making it available when needed, Mullafarry could help support a more secure, affordable and homegrown electricity system for Ireland. The project would also support jobs and local economic development during construction and operation. Through projects such as Mullafarry, SSE continues to play a leading role in Ireland’s energy transition,” Demeuldre said. 

Read more: Ireland’s grid-scale storage growth: 800 MW connected, 2.3 GW in the pipeline