Alinta Energy’s 100MW/200MWh battery energy storage system (BESS) at its Wagerup thermal power plant in Western Australia (WA) has been operating commercially since September, the company has confirmed.
The 2-hour system sits at the Wagerup Power Station, a 380MW gas and distillate-fired plant about 120km south of Perth that provides peaking capacity to the South West Interconnected System (SWIS), WA’s main grid, which operates separately from the National Electricity Market (NEM) in eastern Australia.
Alinta said delivering the project was “no small feat”. The company said challenging site conditions required “significant redesign and remediation”, including raising the platform the BESS sits on and building “substantial retaining infrastructure”.
Alinta credited its delivery partners and suppliers, whose “efforts and expertise were critical”, but did not name them or disclose the project’s cost.
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When Alinta, an energy generator and retailer serving customers in Australia and New Zealand, announced it was building the 100MW/200MWh BESS at the Wagerup thermal power plant in August 2023, it said commissioning would begin in the second half of 2024.
At that time, the company named Shanghai Electric Power Design Institute (SEPD) Australia, a local subsidiary of POWERCHINA-owned SEPD, and Australian solar PV and battery storage provider Sunterra as contractors. The BESS connects to the existing high-voltage transmission infrastructure at Wagerup.
A second, larger system is planned for the same location. In July 2024, Alinta received approval for a 300MW BESS near Wagerup Power Station, with completion expected by October 2027. SEPD Australia and Sunterra were again named as delivery partners.
Russell Slaughter, head of project development at Alinta, said at the time that the second project would “support the introduction of solar and other intermittent renewable energy sources into the existing network”.
Alinta has scaled back elsewhere in its storage portfolio. The company recently discontinued work on the 7.2GWh Oven Mountain pumped hydro energy storage (PHES) project in New South Wales, citing “economic and timing challenges on key elements of the project, including a critical transmission line”.
Western Australia’s grid-scale BESS market
Wagerup joins a SWIS fleet that now includes the two largest BESS in Australia, both near the town of Collie in WA’s southwest.
In February, state-owned utility Synergy completed its 500MW/2,400MWh Collie Battery, built with CATL’s EnerC lithium iron phosphate (LFP) system, representing more than AU$1.6 billion (US$1.1 billion) of investment.
Nearby, French developer Neoen switched on the second stage of its 560MW/2,240MWh Collie BESS in August 2025, using 348 Tesla Megapack 2 XL units. Neoen holds a contract to provide 197MW of 4-hour capacity to the grid operator under WA’s Non-Co-optimised Essential System Services (NCESS) framework.
Utility-scale BESS are already playing a larger role on the SWIS. On 9 May, they supplied a record 37.2% of peak demand on the WA grid, according to Jai Thomas, coordinator of energy at Energy Policy WA, the state’s energy policy agency.
More capacity is on the way through the federal Capacity Investment Scheme (CIS), which underwrites revenue for new clean energy and storage projects. Under CIS Tenders 5 and 6, the government awarded contracts for 1.9GW of renewables and 3.7GWh of battery storage in WA, with all projects due online by 2030.
Successful BESS projects in Tender 6 included Enpowered and Plenary’s 200MW/1,518MWh Collie project, Neoen’s 200MW/1,600MWh Yathroo BESS and Frontier Energy’s 82MW/565MWh Waroona Stage 1.
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