Western Australia's battery storage supplies record 37.2% of peak demand

May 13, 2026

Synergy’s 2,400MWh Collie battery storage system (pictured) is the largest operational BESS in Australia. Image: Roger Cook (LinkedIn)

Utility-scale battery storage systems in Western Australia supplied 37.2% of peak demand on 9 May, marking one of the highest battery storage penetration levels recorded in an isolated grid globally.

The milestone was documented by Jai Thomas, coordinator of energy at Energy Policy WA, who noted on LinkedIn that the record occurred on Saturday evening following a day in which renewables supplied 78% of generation, with renewable energy accounting for 53% of supply across the weekend.

The figures apply to the South West Interconnected System (SWIS), Western Australia’s main grid, which covers approximately 350,000 square kilometres and operates independently of Australia’s National Electricity Market (NEM).