SITELIVE 
What is actually running
Western Australia now holds the country's largest operating battery: Synergy's Collie Battery Energy Storage System, declared operational in February 2026 at 500MW and 2,400MWh, built from 640 battery containers and 160 inverter units on a site opposite the coal-fired Collie Power Station that closes in 2027. It is the third grid-scale battery the state has delivered in just over three years, and it sits a few kilometres from Neoen's 560MW/2,240MWh Collie battery, so one former coal town now hosts roughly 4.6GWh of storage. On the east coast, Akaysha Energy's Waratah Super Battery at the demolished Munmorah power station — 850MW/1,680MWh, built to act as a grid “shock absorber” for New South Wales — reached 700MW and its full rated energy capacity in June 2026. The megawatt-hours are no longer the interesting number. The dates are.
Commissioning, not construction, sets the energisation date
On Saturday 18 October 2025, four hours from completing Hold Point 5 — the final hold point required to transition Waratah to full capacity — one of its three high-voltage transformers failed. Akaysha de-energised a second transformer as a precaution and notified AEMO; the single remaining unit, HVT1, then carried the battery's contracted 350MW System Integrity Protection Scheme obligation for the next seven months. The second transformer returned to service in June 2026, lifting output to 700MW, and full 850MW capacity waits on a replacement for the destroyed unit. One item of HV plant, installed years into the job, cost more schedule than the entire containerised battery scope — for contrast, Neoen's Collie stage 2 moved through commissioning in about four months.
The other reason these projects run long is that the battery is the small part of the works. Around Waratah, Transgrid delivered a $16 million SIPS control system that monitors thirty-six 330kV transmission lines in real time from equipment installed at 19 sites, plus augmentation of 22 substations and four transmission lines. When the scheme detects an imminent overload it signals the battery to discharge and simultaneously instructs paired wind, solar and hydro generators in New England and Snowy to run back — this is a coordinated protection scheme, not a storage asset. Every one of those interfaces carries its own hold points, protection settings, model validation and registration evidence, and any of them can hold energisation while fully installed cells sit idle.
The fleet now sets the price — and then runs out of energy
AEMO's Quarterly Energy Dynamics for Q2 2026 quantifies the shift: year on year, grid-scale daytime charging (1000–1600 hrs) rose 1,009MW (+211%) and evening discharge (1600–2100 hrs) rose 1,066MW (+228%), and batteries became the NEM's most frequent price-setting technology, with charging and discharging together setting price in 36% of dispatch intervals against 17% a year earlier. The same report carries the honest limits. The average price at which battery discharge was marginal fell from $478/MWh to $107/MWh, so the fleet is flattening the very spread its business case rests on; and on the evening of 21 June, South Australia's batteries ran their state of charge below roughly 10% of storage capacity, after which prices spiked above $10,000/MWh for four dispatch intervals — an energy-limited asset that has discharged is a spectator. Duration, not power, is the binding constraint, and saturation is coming: the 2026 ISP records about 67GW in the connections process, some 45GW of it storage, against the 35GW of shallow and medium storage the plan needs by 2050.
System strength is the next contract, and it is unresolved
In April 2026 Transgrid notified the regulator of a material change in circumstances — synchronous condenser costs up sharply, delivery slipping, and AEMO's draft 2026 ISP pushing out NSW coal retirement dates. Its draft reassessment, out for consultation in July 2026, cuts the required condensers from ten large units (or equivalent) to eight and gives grid-forming batteries an expanded role, with a final report due 24 August 2026. The caveat is in the fine print: AEMO does not yet accept grid-forming inverters as counting toward the minimum system strength level — the fault-current question is unsettled — so the expanded battery role is conditional on validation, and the Accelerated Phase 1 condensers remain essential before Eraring retires in 2029. For delivery teams the consequence is concrete: inverter capability, validated plant models and hold-point test evidence are now contract deliverables priced alongside megawatt-hours, and the transformer, substation and protection scope should be run as the critical path from day one. Waratah is the case study — the cells were never the problem.