Australia's biggest battery hits full storage capacity after transformer fix

Australia's biggest battery hits full storage capacity after transformer fix Akaysha's 850 MW Waratah Super Battery now stores 1,680 MWh but still can't deliver its full grid-stabilisation contract, leaving NSW short of a key shock absorber. Akaysha Energy says the Waratah Super Battery, built on the site of the demolished Munmorah coal plant in New South Wales, is now running at 700 MW and 1,680 MWh, its full rated storage capacity, after engineers returned one of two damaged transformers to service.⁴ That matters because Waratah is the largest battery in Australia by capacity, and its job is to act as a "shock absorber" for the NSW grid, absorbing faults on the main transmission lines so that more power can flow on existing infrastructure. The jump to 700 MW, or 82 per cent of the project's 850 MW rating, lifts output from previous operating levels of around 400 MW.⁴ The capacity came back online after repairs to one of the three transformers damaged in what Akaysha called a "catastrophic" incident last October (2025-10), when the project was still in the final stages of commissioning. Full storage is restored. Full contract delivery is not.⁴ Of the 700 MW now available, Akaysha says 350 MW will continue to serve the System Integrity Protection Scheme, the contracted shock-absorber role, while the other 350 MW will be deployed into the National Electricity Market for arbitrage and frequency control services. That split tells you something about the economics. The merchant half earns whatever volatile spot and frequency markets pay; the contracted half is locked.⁴ The delays have already cost money. The Australian Energy Regulator says late delivery of the full SIPS contract, originally due in May last year (2025-05), has cut payments to Waratah and its "paired generators" by more than $90 million.⁴ For a project meant to underwrite reliability as coal retires, that is a pointed reminder that even flagship storage assets carry execution risk. The transformer failure was not a market event. It was hardware, on a single piece of equipment, on a site that until recently burned coal.⁴ Akaysha is not standing still. The company recently reached full output at its 415 MW, 1,660 MWh Orana battery in the central west of NSW, is building the Elaine battery in Victoria, and has just won a firming tender in South Australia for its Brinkworth project. The pipeline is real, and it is concentrated in the states doing the most to replace thermal generation.⁴ The wider context is a storage market straining to keep up with demand. BloombergNEF told its New York summit in April that utilities want far more energy storage than developers can deliver, with high battery pack prices, shipping bottlenecks and other supply-chain constraints damping near-term deployment.³ That squeeze is sharpest in the United States, where Reuters reported battery firms are seeing surging interest from power-hungry AI data centres but face long grid-connection queues and a supply chain heavily dependent on China. Waratah sidesteps the queue problem by being already built and connected. Its lesson is the other one. Getting steel and copper to site, and keeping it running, is where these projects stumble.² Investors have noticed the demand even where the engineering is hard. Fluence Energy shares closed at $24.16 on 8 May 2026, up 98.2 per cent in a single week, after the company disclosed master supply agreements with two hyperscalers and a record $5.6 billion backlog. The stock is still down roughly 39 per cent year to date, and the company carries negative stockholders' equity of $265.88 million against cash of just $36.59 million. Demand is not the constraint. Balance sheets and hardware are.¹ For traders watching the NEM, the signal from Waratah is incremental supply of fast frequency response and arbitrage depth in NSW, with another 350 MW of merchant capacity now chasing spot and frequency spreads. That tightens the bid in volatile intervals and, at the margin, caps the upside on price spikes the battery is built to clip.⁴ The open question is the remaining capacity. Waratah is at 700 of 850 MW, and the second damaged transformer is still out. Akaysha has not said when the final 150 MW and full SIPS delivery arrive. Until they do, the AER's $90 million-plus payment cut keeps accruing against a battery that, on paper, is finally storing everything it was built to hold.⁴