State-owned energy company Synergy has completed the 500MW/2,400MWh Collie Battery Energy Storage System (CBESS) in Western Australia, establishing Collie as home to Australia’s largest operational battery energy storage system (BESS).
The project, located opposite the Collie Power Station, a 350MW coal-fired power station set to close in 2027, represents more than AU$1.6 billion (US$1.12 billion) in investment through Synergy.
Previous reporting on the battery storage system originally stated the CBESS capacity was 2,000MWh; however, media statements from both the Western Australian government and Synergy indicate this has been increased to 2,400MWh.
In doing so, this means that the CBESS is now, officially, Australia’s largest operational battery storage system, trumping the likes of Akaysha Energy’s 1,680MWh Waratah Super Battery and Origin Energy’s 1,770MWh Eraring Battery Stage 1, both in New South Wales, and Neoen’s own Collie Battery, sized at 2,200MWh.
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CATL, a China-headquartered battery manufacturer, provided its EnerC containerised lithium iron phosphate (LFP) BESS solution for the Collie project. CATL joined Sungrow and Tesla as AAA-rated energy storage suppliers in PV Tech Research’s latest Battery StorageTech Bankability Ratings report.
The CBESS deployment utilises 640 battery containers and 160 inverter units, enabling flexible operation to support grid stability and renewable energy integration.
The system represents the third grid-scale battery energy storage project delivered by the Western Australian government in just over three years.
Indeed, Synergy owns another two utility-scale BESS projects in Western Australia. These are the Kwinana BESS 1, a 100MW/200MWh 2-hour duration system at the existing gas-fired Kwinana Power Station, and the 200MW/800MWh Kwinana BESS 2.
Combined with the Collie installation, Synergy’s battery storage portfolio exceeds 3,500MWh of energy storage capacity across Western Australia’s South West Interconnected System (SWIS).
Although Synergy’s CBESS has only just become fully operational, this has not prevented it from playing an important role in various aspects of Australian society.
Ahead of the May 2025 federal election, Prime Minister Anthony Albanese visited the project site to emphasise his support for renewables and energy storage. Albanese and the Labor Party then went on to win that election, beating Peter Dutton and the National-Liberal Coalition, which hedged its bets on nuclear power alongside oil and gas.
Western Australia Premier, Roger Cook, emphasised the project’s role in Western Australia’s energy future.
“Collie has played a vital role in powering Western Australia for decades, and under my government, it will continue to do so. Not only is the town now home to Australia’s biggest batteries, but its future has also been bolstered by our updated Just Transition Plan, which will provide further certainty to the local workforce,” Cook said.
The facility supports the Western Australian government’s commitment to exit state-owned coal-fired power generation by 2030 while maintaining energy security through renewable energy generation and storage infrastructure.
Energy and decarbonisation minister Amber-Jade Sanderson noted: “Synergy’s Collie battery will capture wind and solar generation and use it to power homes when needed. Renewable energy generation and storage backed by gas is the least-cost energy mix for households and businesses and will put downward pressure on prices.”
Collie: the home of some of Australia’s largest battery storage systems
The Collie region continues attracting battery energy storage investment, with Energy-Storage.news reporting a few weeks ago on a third utility-scale battery storage project proposed for the area, sized at 200MW. The duration of this proposed battery storage system has not been disclosed.
One of these projects, Neoen’s 2,200MWh Collie battery storage system, was switched on last year. Stage 1 of the Collie BESS, sized at 219MW/877MWh, began operating in October 2024, less than 18 months after construction commenced.
Building on the success of Stage 1, Neoen completed the second stage of the Collie Battery in August 2025, adding 341MW/1,363MWh. The BESS project utilises Tesla Megapack 2XL units.
Tesla is also exploring a battery re-manufacturing facility near the Collie battery sites, potentially establishing additional industrial capacity in the region. This would initially service a range of battery products in Western Australia and the wider Asia-Pacific region.
The Energy Storage Summit Australia 2026 will be returning to Sydney on 18-19 March. It features keynote speeches and panel discussions on topics such as the Capacity Investment Scheme, long-duration energy storage, and BESS revenue streams. ESN Premium subscribers receive an exclusive discount on ticket prices.
To secure your tickets and learn more about the event, please visit the official website.
