Spotted: As coal mining winds down, innovators are coming up with some novel ways to repurpose disused mines. One of these is Australian startup Green Gravity, which is using vertical ventilation shafts in decommissioned coal mines to store clean energy. 

Green Gravity stores energy using the principles of gravity and kinetic energy. Ultra-heavy weights, made from 30 tonnes of steel coil, are lifted and then lowered in the shafts. As the weights are lowered, the cable holding them passes through a device called a ‘winder’, which is used to turn a motor, generating energy. The weights are lifted using excess renewable energy, then remain at the top of the shaft, holding potential energy, until demand rises, when they are lowered to generate energy to meet that demand. 

While gravity energy storage is not new, Green Gravity aims to save money and resources by using old mine shafts, rather than purpose-built towers. This makes the company’s technology lower cost than similar options. In addition, because it is installed using existing equipment and sites, it uses fewer resources and is thus more environmentally friendly. 

In September 2022, the company announced a partnership with leading Australian artificial intelligence (AI) and automation company xAmplify. Under the partnership, Green Gravity will use xAmplify’s AI to enable digital simulation, data processing, deep learning, and automated operations. In the words of Green Gravity CEO Mark Swinnerton, “Deploying advanced AI platforms will accelerate the rollout of Green Gravity energy storage, bring down the cost of renewable energy, and reduce carbon emissions from the electricity grid.” 

Springwise has previously spotted energy storage systems such as a hi-tech fluid that makes pumped hydro storage more affordable, underground storage for hydrogen, and the world’s first large-scale sand battery.

Written By: Lisa Magloff