The expansion will bring the total number of Tesla Megapacks at the site to 592 units.
The Western Downs Battery, owned and operated by Neoen Australia, is located in Queensland’s Western Downs region, 22km southeast of Chinchilla. UGL has been the construction partner throughout the project, with Tesla supplying its Megapack solution for each phase.
Stage 2 of the Western Downs BESS was delivered ahead of schedule by UGL. In doing so, the company said it was able to re-establish the site quickly after the end-of-year period, with early procurement having begun months ago.
Civil designs have been issued for construction, and the site has officially broken ground for the substation, with focus now on bulk earthworks, trenching and concrete works ahead of Megapack installation.
“Our team is committed to maintaining momentum and delivering each phase with the same focus on safety, precision and performance. It’s exciting to see the project already contributing to Queensland’s grid from its previous stages while we focus on constructing a third stage,” said Jack Connors, UGL project manager.
The first stage of the Western Downs BESS, a 270MW/540MWh system, began operations in June 2025, providing critical grid-reliability and frequency services to Queensland’s electricity network.
That initial phase was followed by Stage 2, which was energised six weeks ahead of schedule, bringing the combined capacity to 540MW/1,080MWh before the current expansion began.
Neoen has claimed that the combined capacity makes it the largest battery storage asset with grid-forming capabilities registered in Queensland’s electricity network, enabling it to provide essential grid services such as inertia and system strength traditionally supplied by conventional synchronous generators.
Stage 2 was confirmed via a 10-year “virtual battery” agreement with Australian energy major AGL Energy, permitting AGL to virtually charge and discharge up to 200MW/400MWh from the Western Downs BESS.
This functionality enables AGL to simulate the operations of a grid-scale BESS, allowing it to charge or discharge as needed.
Construction begins on Neoen’s first 6-hour duration battery storage project
On the other side of the country, UGL has started construction at Neoen’s Muchea Battery, a 164MW/905MWh standalone asset in Western Australia that will be the first 6-hour long-duration energy storage (LDES) project in Neoen’s global portfolio.
The project is being delivered as part of Tesla’s EPC-led approach.
UGL completed early works, including a 1.3km access road upgrade and establishment of the main laydown area, before the end of 2025, delivering safe site access and an efficient start to construction.
The project is located approximately 2km north of Muchea, 43km northeast of Perth, within the Shire of Chittering, and will cover approximately five hectares of freehold land on Byrne Road. It will be connected to Western Power’s network via the adjacent Muchea substation.
UGL disclosed that the early focus has been securing approvals for work within the gas pipeline corridor and the road reserve, with close collaboration between the Dampier to Bunbury Natural Gas Pipeline team, the Shire of Chittering, and Main Roads Western Australia supporting safe, compliant progress.
The on-site workforce has grown steadily throughout the opening months of construction, with bulk civil works progressing and additional teams set to mobilise for civil foundations, electrical works, battery installation and commissioning as the project advances.
“Muchea is an important project for the state, our client and our partners. From day one we have focused on building a strong safety culture, working closely with stakeholders and delivering high-quality outcomes. This project shows what can be achieved through planning, teamwork and a shared commitment to excellence,” said Sandeep Kamath, UGL project manager.
The Muchea BESS was successful in Western Australia’s first Capacity Investment Scheme tender, which saw 2.6GWh of battery storage capacity awarded to support the state’s energy transition.
The project will provide essential peak-demand energy capacity, along with grid stability and reliability services, enabling the integration of more renewable energy into Western Australia’s network.
Over the coming months, the UGL team will complete major civil activities and prepare for the arrival of Tesla Megapacks and associated infrastructure, positioning the project for installation and commissioning.
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