Revised plan being lodged for Mayo energy storage facility
SSE is submitting a planning application to Mayo County Council to revise plans for its consented Mullafarry Battery Energy Storage System (BESS) project in north Mayo.
The application is seeking approval for an 80MW/ 320MWh battery energy storage system capable of storing up to four hours of electricity capacity.
This reserve capacity would provide a reliable power reserve available for use by Ireland’s electricity system operator when energy demand exceeds available generation supply.
The proposed Mullafarry BESS project would be located at an SSE-owned site in the townland of Tawnaghmore Upper, adjacent to the company’s existing 104MW Tawnaghmore Power Station at Killala Business Park.
In April 2025, Mayo County Council granted planning permission to SSE Renewables for a 38-unit battery storage facility with up to two hours of battery storage capacity.
In response to latest advances in storage technology and an increasing demand from the electricity system operator for available power reserves of reliable and flexible electricity capacity, SSE is now seeking to revise its proposals for battery storage at Mullafarry.
The new application is proposing up to 64 battery storage units, together with associated heating, ventilation and air conditioning systems and supporting infrastructure.
The application is also seeking design flexibility to accommodate future advancements in battery technology.
The development would be located within an existing industrial site with construction anticipated to take up to 20 months.
Battery storage plays an important role in supporting Ireland’s transition to a cleaner and more resilient electricity system.
By providing flexibility to store and release electricity in response to grid needs, reliable battery storage technology helps support the integration of renewable electricity onto the grid while enhancing security of supply.
The project would also deliver local economic benefits including construction employment, opportunities for local supply chains, and commercial rates payable to Mayo County Council, supporting local services and infrastructure.
Ghislain Demeuldre, Ireland Head of Onshore Wind, Solar and Battery Development, SSE Renewables, said: “With electricity demand rising in an increasingly volatile world, it’s crucial that we deliver the reliable energy infrastructure Ireland needs for a secure, cleaner and more affordable energy system.
"Our latest plans for battery storage at Mullafarry propose up to four hours of flexible back-up power at 80MW capacity.
“By storing excess electricity when it is available and then releasing it later when it is needed most, our proposed Mullafarry BESS facility would help strengthen the resilience and flexibility of Ireland’s electricity system – and would help deliver a cleaner, flexible, more secure and affordable energy system for Irish consumers.”
The application will be publicised through the required site notices and newspaper advertisements, after which the planning application will be lodged with Mayo County Council.
Following validation by the local authority, the statutory period for formal comments and submissions will open.
Final delivery of Mullafarry BESS would be subject to the project receiving consent approval and a final investment decision by SSE.