Revised plans lodged for major Mayo energy facility

A planning application is being lodged with Mayo County Council in a bid to revise plans for a Battery Energy Storage System project in North Mayo.

In April 2025, Mayo County Council granted planning permission to SSE Renewables for a 38-unit battery storage facility at with up to two hours of battery storage capacity.

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.

The new application is seeking approval for an 80MW / 320MWh battery energy storage system capable of storing up to four hours of electricity capacity.

The company say 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.

SSE say the revised plan is in response to the latest advances in storage technology and an increasing demand from the electricity system operator for available power reserves of reliable and flexible electricity capacity, 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.