en.Wedoany.com Reported - AMPYR Australia has received a 5.3.4 letter from the Australian Energy Market Operator (AEMO), confirming that its 270MW Northern Battery project near Port Augusta in South Australia meets the technical performance standards required for connection to the National Electricity Market (NEM). The company is a utility-scale battery energy storage developer backed by AGP Sustainable Real Assets.
The 5.3.4 letter is one of the most stringent milestones in the Australian grid connection process. Before obtaining the letter, developers must complete power system modelling, hundreds of simulations, network studies, and collaborative workshops with network service providers. Any changes during construction that could affect the project's electrical characteristics must subsequently be updated through a separate R1 process. The receipt of this letter marks the clearing of one of the last regulatory hurdles that Northern Battery must overcome before financial close and the commencement of construction, which AMPYR aims to complete simultaneously in the fourth quarter of 2026.
Northern Battery will be built on the site of the former Northern Power Station. That facility was a 560MW coal-fired power plant retired in 2016, and the project will repurpose the existing substation infrastructure at the Port Augusta site to connect to ElectraNet's transmission network. The site is located at the northern end of South Australia's transmission backbone, enabling the project to cover a large portion of the state's grid.
The project is being developed in partnership with Adelaide-based Green Gold Energy (GGE), with Sungrow and APD Global participating as project partners. AMPYR acquired Northern Battery from GGE in November 2025, with the transaction allowing GGE to continue as a co-development partner. According to AMPYR's project page, Northern Battery has a nameplate capacity of 270MW and a total energy storage capacity of 1,080MWh, configured to operate as an 8-hour battery energy storage system (BESS) when required.
The project will employ grid-forming inverter technology, enabling the battery energy storage system to provide voltage and frequency control services independently of conventional generation sources. This configuration aligns with the broader shift in the NEM to manage system strength in the context of coal-fired power plant retirements. Analysis conducted by AEMO earlier this year shows that grid-forming inverters now feature in 74% of Australia's 33.2GW NEM battery storage project pipeline, a proportion that reflects both the commercial incentives of system strength service contracts and the growing operational experience of the technology across the NEM.
AEMO's 2026 General Power System Risk Review found that grid-forming BESS has demonstrated the ability to support voltage waveform stability, but has not yet been proven to provide protection-grade fault current to the standards required to meet minimum system strength levels. AEMO is conducting a fault current trial to address this issue.
AMPYR's commencement of construction in the fourth quarter of 2026 will make Northern Battery one of the first long-duration energy storage projects in South Australia to enter actual construction following the inaugural Firm Energy Reliability Mechanism (FERM) tender. The tender awarded 15-year capacity contracts to six projects in May 2026, with Northern Battery among the successful bidders.
