Battery storage is booming in Western Australia’s main power system – but new energy generation is urgently needed to meet growing peak demand and retirements of ageing fossil fuel plants, AEMO has warned.
The Australian Energy Market Operator’s 2025 Wholesale Electricity Market Electricity Statement of Opportunities (WEM ESOO) outlines reliability forecasts and investment needs for the South West Interconnected System [SWIS] from 2025-26 to 2034-35.
It signals that while storage capacity is expanding rapidly, firm renewable generation is now critical to maintain system reliability.
“While there has been significant investment in recent years, and ongoing interest, it is prudent to ensure the timely and coordinated delivery of projects within the pipeline,” said Nicola Falcon, AEMO’s Interim Executive General Manager for Western Australia.
Nearly 500 MW of grid-scale battery storage has come online since 2023, with a further 728 MW committed for delivery in 2025-26. Yet, with demand peaks increasingly stretching into the evening, longer-duration storage and additional renewable generation are both required to maintain supply security.
The 2025-26 summer is forecast to have a 50 MW shortfall in dispatchable capacity. This is smaller than past years but could prompt another round of supplementary capacity procurement.
Even with all committed capacity delivered on time, AEMO found that combinations of generator outages and low wind could result in unserved energy exceeding reliability standards between 8:00 pm and 10:30 pm.
Looking further ahead, nearly 1.7 GW of coal and gas capacity is expected to retire by 2032, including Synergy’s Collie and Muja D coal plants and the privately-owned Bluewaters Power Station, which is at risk due to coal supply uncertainty beyond 2027-28.
While over 2.3 GW of new capacity was proposed via expressions of interest this year, much of it battery storage, AEMO has flagged a need for at least 110 MW of new energy-producing capacity by 2027-28. Without it, the system could face a shortfall of over 900 MW.
New grid projects such as Western Power’s CEL-North and East Enhancements are vital to unlocking renewables in key regions like the Mid-West and Goldfields, but AEMO notes delays would exacerbate reliability risks.
“As can be seen from the substantial pipeline, investment interest in the SWIS remains strong,” said Falcon.
“This WEM ESOO highlights the importance of getting the right mix of generation and storage to continue providing secure and reliable electricity.”