Disused mine shafts at the Russell Vale Colliery could have a second life generating renewable energy. Photo: Keeli Royle.
An experimental energy storage trial will happen right here in Wollongong.
Green Gravity has secured an agreement from Wollongong Resources for disused mineshaft number four at Russell Vale to be the site of the world’s first deployment of the technology.
Green Gravity proposes to generate energy at off-peak times for other renewables, such as solar, by dropping large concrete blocks down mine shafts and harnessing the kinetic energy they generate.
The blocks can be hauled back up using energy generated during peak periods.
It effectively acts as a large-scale storage system for excess energy generated during the peak.
The company has spent the past two years conducting research and development in its lab at the Port Kembla Steel Works and is ready to move to the next phase.
Green Gravity is completing engineering studies and regulatory approvals for the deployment of gravitational energy storage at Russell Vale.
A spokesperson said the team expected to begin technical trials in 2026.
The trials will include repurposing 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 kilowatts (150 kW) of power.
The Russell Vale mine was an active coal mine between the late 1800s and 2023 and is now in care and maintenance.
It’s one of many legacy coal mines across the region, and a Green Gravity spokesperson said the eight mine shafts held by Wollongong Resources have the potential to deliver more than 100 MWh of clean energy storage for the greater Sydney metropolitan area.
Mark Swinnerton, Founder and CEO of Green Gravity, said there were other factors that made Wollongong an ideal location for the technology.
“The region has large industrial power demand combined with a rich coal mining history,” he said.
“The demonstration plant at Russell Vale mine will deliver world-class testing data.
“By placing and retrieving multiple weights 400 metres underground using fully autonomous systems, we will have the opportunity to validate the incredible safety and environmental credentials of Green Gravity’s technology.”
If Green Gravity’s trials are a success it will place them firmly at the forefront of the sector, with unique intellectual property in the use of multi-weight gravitational systems capable of delivering very high energy density.
Trials will be conducted at 150 kilowatts of power, but the mechanical components and key control systems will be tested at a scale sufficient for future commercial use of the technology, and could deliver up to 10 megawatts of power over periods of 8 to 20 hours.
Wollongong Resources company secretary Sanjay Sharma said the business was delighted to support the trial.
“We’re committed to finding smarter ways to reduce emissions and support a low-carbon future,” Sanjay said.
“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.”
