Finnish marine and energy technology group Wärtsilä was contracted to supply the BESS solution in a deal booked in Q4 2024 and announced in February 2025, covering engineering design, supply, commissioning and a 15-year service agreement.

The system uses Wärtsilä’s Quantum High Energy hardware and the company’s GEMS Digital Energy Platform and is designed to operate in grid-forming mode, enabling it to provide synthetic inertia and faster response times to stabilise the grid as coal-fired generation retires from the Victorian system.

When Wärtsilä launched the Quantum High Energy product in late 2023, the company said it delivered 9% greater energy density than the previous generation through the use of 306Ah lithium-ion cells, alongside fire safety improvements including active dehumidification, prefabricated fire walls between units and a dual sprinkler system.

That higher energy density directly reduces the number of units required per site and, by extension, the footprint and logistics complexity of delivering a project at Wooreen’s scale, where 1,038 individual units have now been received, staged, and installed.

In July 2025, EnergyAustralia sold a 50% share in the 1,400MWh Wooreen BESS to Thailand-based energy firm Banpu Public Company. The deal cost in the region of AU$700 million (US$490 million), with Banpu to provide an equity injection of AU$110 million.

The construction programme at Wooreen has involved multiple contractors working across parallel workstreams since the project broke ground in February 2025, when EnergyAustralia started construction on the 350MW/1,400MWh BESS days after reaching financial close, with Victorian Energy Minister Lily D’Ambrosio attending the commencement ceremony.

Zenviron, the joint venture between engineering group Monadelphous and renewable energy developer ZEM Energy, was awarded the balance-of-plant contract covering design, construction, installation and commissioning.

The Wooreen project received support in the first round of the Australian government’s Capacity Investment Scheme (CIS), which has been the primary federal mechanism for underwriting new storage investment across the National Electricity Market (NEM).

EnergyAustralia’s broader storage portfolio extends beyond Wooreen, with the company having also reached financial close on the 50MW/250MWh Hallett BESS in South Australia in February 2026, a project using NHOA Energy as battery integrator and targeting commercial operations by mid-2027.

The completion of battery installations at Wooreen brings the project to the threshold of commissioning, the phase in which individual units are progressively energised, tested and integrated into the site’s control systems before grid connection is established.

For a project of 1,038 units, that process is typically sequenced in blocks rather than all at once, meaning partial capacity is likely to be available before the full 350MW rating is confirmed by AEMO.

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