Green Gravity Energy

Green Gravity Energy, founded in 2021 by Mark Swinnerton, is a Wollongong-based company developing a gravitational energy storage system. Swinnerton, with over 25 years of experience in the mining, metals, and manufacturing sectors, including executive roles at BHP, established the company to address climate change by providing a solution for renewable energy storage. His background in these heavy industries provides a foundation for leading the development of gravitational energy storage technology for the natural resources sector.

The company's core business revolves around repurposing legacy mine shafts for utility-scale, long-duration energy storage. The technology operates by lifting and lowering heavy weights in these shafts to store and release energy. When renewable energy sources like solar and wind generate surplus power, it is used to lift the weights, converting electrical energy into gravitational potential energy. To dispatch the energy, the weights are lowered, causing a generator to spin and create electricity. This system is designed for mid-duration storage applications of four to 24 hours with a target of 80% energy efficiency. For example, a 40-metric ton weight has the potential to store up to 10 kWh of energy for every 100 meters of depth in a mineshaft.

Green Gravity's business model involves developing, installing, and operating these systems, targeting energy generators and mining companies as key clients. By reusing existing mine infrastructure, the company aims to offer a low-cost energy storage solution with a long asset life of 30 to 50 years, avoiding the need for water, chemicals, or extensive land use. The technology utilizes proven components from the mining and manufacturing sectors, such as cables, motors, and mine winders. In October 2024, the company secured AUD 9 million in a Series A funding round from investors including HMC Capital, BlueScopeX, Pacific Channel, and Sumitomo Corporation's subsidiary, SCAP H. This capital is intended to complete product development, including engineering and physical testing, to enable commercial deployment. The company is commissioning a demonstration plant at BlueScope's Port Kembla Steelworks and is exploring deployment at various mine sites, with over 80 options under review.

Keywords: gravitational energy storage, renewable energy, mine shaft repurposing, long-duration storage, clean technology, grid stability, circular economy, sustainable infrastructure, energy transition, heavy industry innovation