Who will supply historic gold mining centre’s grid-saving vanadium flow battery?

The Western Australia state government is to begin evaluating proposals for a 10-hour vanadium flow battery to support the grid around the gold mining town of Kalgoorlie after reporting “significant interest” in its tender that closed on Monday.

The deadline for proposals for the Kalgoorlie Vanadium Battery Energy Storage System (VBESS) elapsed on Monday afternoon. The state government has promised up to $150 million to support the ground-breaking project, which it wants sized at 50 megawatt (MW) and 500 megawatt-hour (MWh).

A vanadium flow battery for Kalgoorlie was one of several election promises premier Roger Cook made in the lead up to the 2025 election, to help address supply issues and grid security which had plagued the town and surrounding areas, which is connected to the state’s grid with a relatively thin transmission line.

At the time, 50MW, 10-hour capacity would have been the largest of its type in the country. But since then Idemitsu Australia has unveiled a proposed 108 MW/ 864 MWh (or 8 hours) vanadium flow battery to be built at a new clean industries precinct at the site of the former Muswellbrook coal mine.

The Cook government says the response to the initial expressions of interest (EoI) process showed “significant industry interest,” which led to an invitation for final VBESS proposals to be submitted by 4:00pm (AWST) on Monday, 20 July 2026.

The state government also hopes that the Kalgoorlie VBESS will help to support the adoption of long-duration storage technologies across the state and catalyse the development of a local vanadium industry.

The Kalgoorlie VBESS must be developed in a single staged development that begins operations by the end of 2029 with the full 50 MW/500 MWh capacity and grid forming capability.

The winning bidder will also be responsible for identifying and securing all necessary land and tenure agreements, even if that land is owned by DevelopmentWA, the state government’s central land and development agency.

The state government says it will not be providing more than the promised “up to” $150 million in grant funding, with proponents required to demonstrate that their proposals do not depend on any additional state government financial support.

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