Hitachi Energy and AusNet enable Victoria’s largest grid-scale battery connection

Australia is accelerating toward net-zero emissions by 2050, with over 35 percent of electricity already generated from renewables such as wind and solar. The next step is large-scale energy storage: capturing clean power when it’s abundant and supplying it when demand peaks.

A major milestone in this transition is Origin’s Mortlake Battery Energy Storage System (BESS) in Victoria. Once operational, the 300 MW / 650 MWh facility will be one of the state’s largest, supporting grid stability and powering the equivalent of 135,000 homes.

The Challenge: Connecting critical infrastructure on time, without compromise

As renewable generation expands, maintaining grid stability has become increasingly complex. Connecting large-scale batteries requires specialised high-voltage infrastructure delivered on time and to the highest standards. For AusNet, Victoria’s largest diversified energy network, this meant designing and installing the transmission connection for Mortlake BESS—including two 500 kV transformers—without compromising reliability or safety.

Collaborating to deliver on a bold vision

To meet these demands, AusNet and Hitachi Energy collaborated closely from the project’s outset, co-developing technical specifications and ensuring supply-chain resilience. Hitachi Energy supplied two 500 kV, 180 MVA transformers, engineered for dynamic loading and harsh environments, featuring advanced cooling, low-loss design, and digital monitoring for efficient and reliable performance.

“This project reflects Hitachi Energy’s mission to advance a sustainable, flexible, and secure energy system. Our 500 kV transformers play a vital role in converting stored battery energy into high-voltage power. Once installed at Mortlake Terminal Station, they will enable efficient transmission into the national grid, connecting thousands of homes to clean, reliable energy,” said Dinesh Kumar, Market Manager, Business Unit Transformers, Hitachi Energy.

Powering the future

The Mortlake BESS connection builds on the partners’ earlier success at the Golden Plains Wind Farm, now powering over 765,000 homes. Together, AusNet and Hitachi Energy are helping deliver a smarter, more sustainable national grid.

Watch the video: AusNet and Hitachi Energy enable Victoria’s largest grid-scale battery connection