The Lumcloon 100MW Battery Energy Storage System (BESS), and 110kV air insulated substation is a new, innovative energy storage facility in Offaly. Jennings O'Donovan & Partners Limited was appointed as owner’s engineer as well as special point of contact with EirGrid throughout the detailed design, construction and commissioning period. The batteries are based on cutting-edge storage technology to mitigate the intermittency of electricity generated from renewable sources such as wind and solar. The new BESS plant is in keeping with the heritage and tradition of power generation in the area, albeit with modern and innovative technology, reflecting the evolution of the power industry in Ireland. The successful delivery of this innovative project included international collaboration between Korean, Irish, Spanish and German contractors, suppliers and engineers.