Akaysha Energy has reached final commercial operations at its Waratah Super Battery in New South Wales, Australia, closing out a commissioning process that ran through a transformer failure and months of reduced capacity.
The 850MW/1,680MWh project is built on the site of the former Munmorah coal-fired power station near Budgewoi. It was commissioned by the NSW government and built, owned and operated by Akaysha, a battery storage developer backed by global investment firm BlackRock.
With a power output of 850MW, the Waratah Super Battery is the most powerful battery energy storage system (BESS) in Australia.
Waratah is the battery component of the wider Waratah Super Battery site, which also includes a System Integrity Protection Scheme (SIPS) Control System delivered by Transgrid, the operator of NSW’s high-voltage transmission network.
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Akaysha said the two are designed to help the grid respond quickly to disturbances, acting as a shock absorber for the network while supporting the flow of more renewable energy across the transmission system.
Under the SIPS arrangement, Transgrid can signal the battery storage system to inject energy while instructing paired generators to adjust their output, with the control system monitoring 36 transmission lines in real time.
That allows existing lines serving the Hunter, Sydney and Illawarra regions to carry more power than they otherwise could, as a stopgap until the Hunter Transmission Project connects inland Renewable Energy Zones (REZs).
Akaysha said the project attracted more than AU$1 billion (US$690 million) in private investment and involved around 1,000 people across design and construction, including 170 workers on site at peak.
“Bringing the Waratah Super Battery to final commercial operations is a landmark moment for Akaysha Energy, our project partners and most importantly, for NSW,” said Akaysha CEO Nick Carter.
Akaysha thanked EnergyCo, the NSW state-owned corporation that ran the procurement, along with the NSW government, Transgrid and delivery partners Consolidated Power Projects Australia, Hitachi Energy, Wilson Transformer Company, REPT Battero and EVE Energy.
Final operations follow a year of reduced capacity
The path to this point was interrupted. Waratah discharged its first full 850MW output to the National Electricity Market (NEM) on 10 October 2025, a record for a single battery storage system discharge from NSW at the time.
However, things took a turn when that same month, High Voltage Transformer 3 (HVT3) suffered a “catastrophic failure”. HVT2 was taken offline as a precaution, leaving the facility at 350MW and meeting only an interim SIPS obligation at that level.
Dr Tom Harries, partner at specialist battery storage insurance broker NARDAC told Energy-Storage.news at the time that the estimated total losses from the failure at AU$50-80 million, depending on how quickly replacement transformers could be secured.
In February, Akaysha confirmed a third-quarter 2026 delivery timeline for the HVT3 replacement, manufactured by Wilson Transformer Company under the contract with Consolidated Power Projects Australia. Using a domestic manufacturer avoided the 12-18 month lead times typical of specialised transformers sourced overseas.
HVT2 came back first. In June, Waratah returned to 700MW and its full 1,680MWh energy capacity, with 350MW committed to the Transgrid SIPS contract and the other 350MW available to trade in the NEM. Running at 350MW for most of the commissioning period had left Akaysha receiving roughly half of its expected contracted revenue.
Earlier this month, Waratah briefly recorded its full 850MW output before discharging 701MW two days later, a figure consistent with its contracted 700MW SIPS obligation, according to Open Electricity data.
The project’s supply chain also changed during delivery. Original battery provider Powin filed for Chapter 11 bankruptcy protection, Hitachi Energy took full ownership of Powin’s power conversion partner, Eks Energy, and US integrator FlexGen acquired the bulk of Powin’s assets and took over servicing its global project portfolio, including Waratah.
The SIPS contract gives Waratah a revenue base that does not depend on those spreads. Transgrid contracted 700MW and 1,400MWh of guaranteed capacity, with payments adjusted through an annual process with the Australian Energy Regulator to reflect the service actually provided.
Akaysha’s own pipeline continues to advance. Its 311MW/1,244MWh Elaine BESS in Victoria has installed a second high-voltage transformer and is backed by AU$460 million in construction financing and a 15-year virtual toll, with Snowy Hydro covering 220MW. In NSW, its 415MW/1,660MWh Orana BESS reached commercial operations in June within the Central-West Orana REZ.
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