Origin Energy says it will build a $400 million, 650 MWh battery storage system at its gas-fired Mortlake Power Station in Victoria. 

The Mortlake battery, boasting a capacity of 300 MW, is poised to play a critical role in stabilising the grid and facilitating the integration of renewable energy, linked to the budding wind and solar farms in Victoria’s South West Renewable Energy Zone. 

Origin has selected Fluence, a global energy storage systems supplier, to execute the project, with site preparation and civil works slated to commence in the coming months. 

The battery is expected to be fully operational by late 2026, delivering up to 650 MWh of output.

This initiative is part of Origin's broader strategy to augment its renewable energy and storage capacity, aiming to achieve up to 4GW of wind, solar, and storage across its portfolio by 2030. 

The Mortlake project, in particular, has been awarded conditional grant support from the Australian Renewable Energy Agency (ARENA).

ARENA's support is tied to the project's deployment of grid-forming inverter technology, deemed essential for replicating the grid services traditionally offered by conventional generators.

The choice of Mortlake, Victoria’s largest gas-fired generator with a 566 MW capacity, as the site for this large-scale battery is part of a growing trend among Australian utilities. 

By co-locating storage solutions with existing fossil fuel facilities, companies are leveraging existing energy infrastructure, such as substations and power lines, to expedite the transition to renewable energy while maintaining grid stability.

Plans for a series of similarly big batteries have been announced in South Australia and Queensland, next to proposed solar farms and existing gas-fired power stations.