The Waratah Super Battery, Australia’s most powerful grid-scale energy storage system, successfully completed critical System Integrity Protection Scheme (SIPS) tests this week, reaching its full rated output of 850 megawatts (MW) and 1,650 megawatt-hours (MWh). The significant milestone, achieved between September 7 and September 10, 2026, confirms the battery’s operational readiness to act as a vital “giant shock-absorber” for the New South Wales electricity grid, enhancing stability and reliability for millions of consumers.
Owned and operated by Akaysha Energy, a BlackRock-backed battery storage developer, the Waratah Super Battery is located on the site of the former Munmorah coal-fired power station near Budgewoi, NSW. Its primary function is to provide SIPS services under contract to transmission operator Transgrid. This involves instantaneously injecting or absorbing energy to stabilise the grid during unexpected events, allowing existing transmission infrastructure serving the Hunter, Sydney, and Illawarra regions to operate at higher capacities.
The latest tests mark a crucial step following the earlier “catastrophic failure” of one of its High Voltage Transformers (HVT3). Akaysha Energy had committed to a Q3 2026 delivery timeline for the replacement transformer, manufactured domestically by Wilson Transformer Company, and these recent operational successes indicate that timeline has been met.
Critical SIPS Testing Details
According to data from Open Electricity (formerly OpenNEM), the Waratah Super Battery briefly reached its full rated output of 850MW on September 7, 2026. This was followed by a comprehensive two-hour discharge test on September 9, where the facility delivered 701MW, consistent with its full contracted SIPS service to Transgrid. A second, equally successful two-hour discharge test, averaging 700MW, was conducted on September 10, demonstrating sustained capability. For good measure, the battery also charged at its full 850MW capacity for a short period, showcasing its complete operational range.
“Great day of testing today up at the Waratah Super Battery,” Akaysha CEO Nick Carter shared on LinkedIn. “SIPS test #2 conducted at 700MW. Also had a bonus 850MW charge for a short time. Plant performance was good and is a testament to the whole Akaysha Energy team and all our partners for the endeavour and perseverance to get to this point. Onwards…. ”
These verified tests are essential for Akaysha Energy to fully secure its long-term SIPS contract, which has faced delays since its original schedule. The battery has been operating on an interim basis since late last year, but these recent demonstrations are expected to pave the way for its full contractual activation.
Reinforcing NSW’s Energy Security
The Waratah Super Battery plays a pivotal role in NSW’s energy transition strategy. By providing critical system security, it enables greater utilisation of existing transmission lines, effectively bridging the gap until new transmission projects, such as the Hunter Transmission Project, are completed. This mechanism allows more renewable energy from regional generators to flow into population centres without risking grid instability.
Australia’s energy market operator, AEMO, has consistently highlighted the growing need for dispatchable capacity and system security services as the National Electricity Market (NEM) transitions from a coal-dominated system to one reliant on intermittent renewable sources like solar and wind. The 2026 Electricity Statement of Opportunities (ESOO) reinforced that timely investment in generation, storage, and transmission is crucial to maintain reliability as demand grows and ageing coal generators retire.
Grid-scale batteries, particularly those with grid-forming capabilities like the Waratah Super Battery, are considered critical by AEMO for supporting the rollout of inverter-based energy generation. The first quarter of 2026 saw battery energy storage systems in the NEM more than triple their daytime-to-evening energy shifting, demonstrating their increasing importance in managing solar penetration and peak demand.
This development aligns with broader federal and state commitments to expand energy storage. The Australian Government’s Capacity Investment Scheme (CIS), for instance, has successfully tendered for 15 energy storage projects totalling 4.2 GW / 16.1 GWh, unlocking approximately $6 billion in private investment across NSW, Queensland, Victoria, and South Australia. While the Waratah Super Battery is a distinct project, it underscores the significant investment and strategic importance placed on large-scale battery storage solutions to manage Australia’s evolving energy landscape. Homeowners considering their own energy storage solutions can also explore options to Maximise Your Home Battery Savings: Earn $1,000+ Annually with a VPP in 2026 and understand their role in a decentralised grid. For those looking to install solar panels alongside a battery, understanding Solar System Installation Costs in Australia 2026: A Complete Guide is also crucial.
The successful testing of the Waratah Super Battery reinforces confidence in large-scale battery technology to underpin Australia’s transition to a more renewable and resilient energy future, particularly in high-demand states like NSW. The achievement marks a significant step towards a more secure and stable grid, demonstrating the tangible benefits of strategic energy infrastructure investment.