Australia’s electricity transition has reached another major milestone.
The Waratah Super Battery in New South Wales is now fully operational, after receiving approval to operate at its full rated capacity from the Australian Energy Market Operator (AEMO) on 28 September 2026.
Built at the former Munmorah coal-fired power station site on the NSW Central Coast, the facility can deliver 850 megawatts (MW) of power and store 1,680 megawatt-hours (MWh) of energy. Akaysha Energy built, owns and operates the battery, while the NSW Government’s EnergyCo commissioned and oversaw the wider project. Transgrid operates the project’s System Integrity Protection Scheme (SIPS) control system.
The milestone is important for a reason that goes beyond the size of the battery.
Waratah has been designed not simply to store electricity and sell it back to the grid, but to respond rapidly when the transmission system comes under stress. In that role, it functions as what project planners describe as a “shock absorber” for the electricity network.
That makes the project a useful illustration of where Australia’s electricity system is heading: more wind and solar generation, more storage, more sophisticated grid controls and continued investment in transmission as ageing coal generators retire.
What happened at Waratah?
The Waratah Super Battery reached final commercial operations on Monday, 28 September, completing a commissioning process that began with construction in 2023.
EnergyCo confirmed that the battery had received approval to operate at full capacity from AEMO. The agency said the project is now helping NSW support the growing amount of renewable energy entering the electricity system while strengthening the grid during major disturbances.
The battery sits at the former Munmorah Power Station, which closed in 2012 after operating for roughly five decades. Rather than building an entirely new energy facility on an undeveloped site, the project repurposed part of an existing industrial location with access to established transmission infrastructure.
Construction of the battery began in May 2023 and was completed in October 2024. The project then moved through energisation, registration, testing and staged commissioning before reaching full commercial operation.
That journey was considerably longer than originally expected.
The numbers behind the Waratah Super Battery
The headline figures are substantial:
- 850 MW — maximum power output
- 1,680 MWh — total rated energy storage
- 700 MW — contracted continuous power capacity for the project’s System Integrity Protection Scheme service
- 1,400 MWh — guaranteed usable energy storage capacity under the SIPS arrangement
- 2,600 or so battery units — the project was expected to include roughly this number of individual battery units
- About 1,000 people — involved in the project’s design and construction
- More than A$1 billion — private investment attracted by the project, according to Akaysha Energy.
One distinction is particularly important.
850 MW and 1,680 MWh measure different things.
The megawatt figure describes how quickly the battery can deliver or absorb electricity. The megawatt-hour figure describes the amount of energy it can store.
In simple terms, if the battery were delivering its full 850 MW output continuously, its 1,680 MWh rated storage would correspond to roughly two hours of output. Actual operation can differ substantially because the battery is not designed simply to run flat from full charge to empty. Its role includes rapid grid response, market participation and system-security services.
The project therefore should not be understood simply as an enormous two-hour backup generator.
Its more unusual feature is how the battery is integrated with the transmission network.
Why Waratah is more than a giant battery
The Waratah project combines three important elements: battery storage, a sophisticated control system and transmission infrastructure.
At the heart of its grid-security role is the System Integrity Protection Scheme, or SIPS.
When a major transmission problem occurs — potentially caused by events such as bushfires, lightning strikes or fallen trees — the system can detect the disturbance and rapidly activate the battery.
The battery can inject electricity into the grid while paired generators simultaneously reduce their output. This coordinated response can help prevent transmission lines from becoming overloaded during a network contingency.
That is different from the way many people imagine a battery operating.
A household battery might charge during the day and discharge during the evening. Waratah can also participate in the electricity market, but its SIPS function is about system security and speed.
The objective is to buy the electricity network time.
Instead of immediately requiring new transmission capacity to handle every possible contingency, a fast-response battery can temporarily alter the balance of power flowing through the network while the underlying disturbance is resolved.
EnergyCo has described this as allowing more power to flow through existing parts of the network.
Why batteries matter as renewable energy grows
The wider Australian electricity system is changing quickly.
Solar and wind generation can produce large amounts of electricity when weather conditions are favourable, but their output varies. At the same time, electricity demand does not necessarily rise and fall at exactly the same time as renewable generation.
Storage helps bridge those differences.
AEMO’s 2026 Integrated System Plan, published in June, says renewable generation connected through transmission and distribution, supported by storage and backed by gas generation, forms the least-cost pathway for supplying secure and reliable electricity through the transition as coal plants retire.
The shift is already visible in the National Electricity Market.
AEMO reported that renewables supplied 46.5% of NEM generation in the first quarter of 2026, the highest renewable share recorded for a first quarter. The same report said batteries were playing a growing role in the electricity market.
That creates a growing need for infrastructure that can do more than generate electricity.
The grid also needs resources capable of responding quickly, shifting electricity across time, managing sudden changes and supporting system security.
Waratah is one response to that problem.
From Munmorah coal to modern grid infrastructure
The location tells another part of the story.
Munmorah was once part of NSW’s coal-fired electricity infrastructure. The power station operated for approximately 50 years before closing in June 2012.
Today, part of that former industrial site is occupied by one of Australia’s largest battery projects.
The choice was not simply symbolic.
EnergyCo selected the former power-station site because it is already connected to important electricity infrastructure. The project can therefore make use of an existing industrial location and nearby transmission facilities rather than starting from scratch elsewhere.
That model could become increasingly relevant as Australia retires older coal-generation sites.
The challenge is not only replacing the electricity produced by ageing generators. It is also replacing some of the services those generators provided to the wider electricity system.
Large batteries, transmission upgrades and other flexible technologies can perform some of those functions in different ways.
Waratah does not replace Munmorah’s former coal generation on a one-for-one basis. A battery is fundamentally different from a thermal power station. But the transformation of the site illustrates the broader change underway in Australia’s electricity infrastructure.
The difficult road to full operation
The final milestone also comes after a serious setback.
Waratah had already entered partial commercial operation in August 2025, with 350 MW and 700 MWh of battery capacity available. The project was expected to progress toward full operation later that year.
Then, on 18 October 2025, one of the project’s three high-voltage transformers suffered a major internal failure during commissioning.
Akaysha said the incident occurred only four hours before completion of the project’s fifth and final testing hold point required to transition to full capacity. The failed transformer, identified as HVT3, was rendered inoperable. A second transformer, HVT2, was also temporarily de-energised as a safety precaution.
The failure left the project operating at 350 MW for an extended period.
The incident was significant because the problem was not with the battery cells themselves. It involved high-voltage grid infrastructure that is essential for connecting the battery’s power to the electricity network.
Akaysha later said investigations found significant internal damage to HVT3, including damage to its windings and an overpressure event that ruptured the transformer tank wall. The company said the investigation into the cause continued.
A replacement transformer had to be manufactured and installed.
A staged return to full capacity
The project gradually recovered during 2026.
In June, Akaysha announced that Waratah had returned to 700 MW of power availability and its full 1,680 MWh rated energy capacity after HVT2 was returned to service.
At that stage, 350 MW remained committed to the SIPS service, while another 350 MW could participate in the National Electricity Market. Full 850 MW operation depended on the replacement of HVT3.
The replacement transformer was subsequently installed and commissioned.
Independent electricity-market analysis from WattClarity reported in September that Waratah had completed tests of its full 700 MW SIPS capability, including two successful tests during the month, before the project reached final commercial operations.
The sequence demonstrates an often-overlooked reality of large energy projects: installing thousands of battery modules is only one part of the engineering challenge.
Transformers, protection equipment, control systems, substations, transmission connections and regulatory testing all have to work together before a project can operate at its advertised rating.
What the project means for Australia’s grid
Waratah’s significance is therefore less about setting a single battery-size record and more about demonstrating how storage can become part of the architecture of a renewable-heavy grid.
AEMO’s 2026 Integrated System Plan explicitly identifies storage and transmission as central components of Australia’s electricity transition.
That is because building renewable generation alone does not solve every grid problem.
A large solar farm can generate substantial electricity during periods of strong sunlight. A wind farm can produce large amounts of power when wind conditions are favourable. But the electricity system also needs resources that can respond when conditions change, demand rises or a transmission link suddenly becomes unavailable.
Batteries are particularly valuable in those situations because they can respond extremely quickly.
Waratah adds another layer: its SIPS arrangement links the battery’s response directly to the stability of the transmission network.
At maximum output, the NSW Government says the project can supply enough power to cover the peak demand of up to 340,000 NSW households. That figure is a measure of instantaneous power capability rather than a statement that the battery can continuously supply those homes for an entire day.
That distinction matters when assessing what a battery actually does.
What comes next
The Waratah Super Battery is now entering the phase for which it was ultimately designed: operating as part of NSW’s electricity system rather than as a project still undergoing commissioning.
Its role will combine grid-security services with participation in the National Electricity Market, while the wider Waratah project continues to work alongside transmission infrastructure and paired generation resources.
The broader challenge for Australia is much larger than one battery.
AEMO’s long-term planning identifies the need for substantial investment in generation, storage and transmission as coal-fired generation retires and renewable generation expands.
Waratah is consequently better understood as one piece of a much larger infrastructure rebuild.
The old Munmorah coal station once represented a centralised model of electricity generation: fuel arrived at a large power station, electricity was generated there and transmission lines carried it to consumers.
The Waratah site now represents a different model.
Electricity can be generated elsewhere, stored when conditions allow, dispatched when needed and used to protect the transmission network when an unexpected event occurs.
That is the significance of the battery’s full operation.
Australia is not simply replacing one power station with one battery. It is gradually assembling a more complex electricity system in which generation, storage, transmission and fast-response controls have to work together.
Waratah’s journey — from a former coal site, through construction and a major transformer failure, to full commercial operation — offers a particularly clear example of that transition.
For Australia’s renewable-energy future, the battery itself is only part of the story. The bigger story is the grid being built around it.
