Green Gravity, Wollongong Resources target gravitational energy storage trial at Russell Vale mine

Green Gravity and Wollongong Resources have executed a binding agreement to deploy gravitational energy storage trials at the Russell Vale mine, in New South Wales, Australia.

Building on the MoU announced in December 2023, Green Gravity and Wollongong Resources have worked closely to assess the Russell Vale site for its suitability to accommodate gravitational energy storage. Multiple mine shafts at the site are well suited to the deployment of Green Gravity technology, with the #4 mine shaft confirmed as the site of the world’s first deployment of the breakthrough technology, Green Gravity says.

Green Gravity is completing engineering study and regulatory approvals for the deployment of gravitational energy storage at the Russell Vale #4 mine shaft. The technical trials will include the repurposing of key infrastructure at the site, alongside installation of new electrical and mechanical components. The site will remain non-grid connected during trials, with energy storage tests at 150 kW of power. The exchange of energy will be tested at up to 400 m of depth, underpinning scaled testing of the technology.

The Russell Vale mine, located in Wollongong, was an active coal mine between the late 1800s and 2023, after which it entered care and maintenance. The site is positioned in a region with multiple operational and legacy coal mines. Wollongong Resources holds eight mine shafts in the Illawarra with the potential to deliver more than 100 MWh of clean energy storage within the greater Sydney metropolitan area.

Green Gravity deployed initial technical trials at the Gravity Lab™ during 2023. The facility, located at BlueScope’s Port Kembla Steelworks, has delivered critical technical performance data for the deployment of gravitational long-duration energy storage. The Gravity Lab can test the movement of 16 weights across two simulated mine shafts. The translation of technical knowledge to the Russell Vale #4 mine shaft production trials will enable the important validation of the technology in the active deployment environment.

Securing binding access to the Russell Vale #4 mine shaft is a significant step in the global deployment of underground gravitational energy storage. Green Gravity already holds key intellectual property in the use of multi-weight gravitational systems capable of delivering very high energy density. Translating the technology to commercial-grade operations at the Russell Vale #4 mine shaft will position Green Gravity at the forefront of the sector, it says.

This will be the first global trial of a technology of this kind, according to Green Gravity.

While trials will be conducted at 150 kW of power, the mechanical components and key control systems will be tested at a scale sufficient to underpin future commercial deployments of the technology. Commercial application of Green Gravity’s gravitational energy storage technology is expected to deliver increments of up to 10 MW of between eight and 20 hours of duration at individual mine shafts.

Green Gravity has commenced the final stage of feasibility study to enable permitting and construction of the demonstration plant. The company expects to make a final investment decision on the capital project within months, which supports an objective of advancing large-scale production trials during 2026.

Mark Swinnerton, Founder and CEO of Green Gravity, said: “Wollongong is an ideal location for deploying our innovative clean energy technology. The region has large industrial power demand combined with a rich coal mining history. This announcement shows that gravitational energy storage has an important role to play in transitioning our urban and industrial energy mix toward low carbon sources.”

“Green Gravity has previously announced feasibility assessment for commercial deployment of the technology at more than 75 mine shafts. With a current deployment pipeline of 10 GWh, Green Gravity is well positioned to deliver significant impact to the clean energy transition.

“The demonstration plant at Russell Vale mine will deliver world-class testing data. By placing and retrieving multiple weights 400 m underground using fully autonomous systems, we will have the opportunity to validate the incredible safety and environmental credentials of Green Gravity’s technology.”

Sanjay Sharma, the Company Secretary of Wollongong Resources, said: “At Wollongong Resources, we’re committed to finding smarter ways to reduce emissions
and support a low-carbon future. Our partnership with Green Gravity marks an exciting step forward – trialling a world-first clean energy technology right here in Australia. This project not only showcases innovation, but also highlights how legacy coal infrastructure can be transformed into productive assets that serve a cleaner, more sustainable future.”