Edinburgh-based Gravitricity’s GraviStore system raises and lowers heavy weights in old mine shafts, offering an energy storage technology with some of the best characteristics of other forms of energy storage. Future GraviStores could store more than 20MWh, providing long-duration storage and rapid power delivery to distribution networks and large power users.
Unlike batteries, the Gravitricity system can operate for decades without any loss in performance. In 2021, the company operated a 250kW, grid-connected demonstration project using a 15m-high rig at the Port of Leith in Edinburgh. The demonstrator used two 25-tonne weights suspended by steel cables. In a series of tests, the weights were dropped to generate power and verify the response speed.
The company is now planning a full-scale commercial project and is conducting feasibility studies across Europe in locations where mines are coming to the ends of their lives.
The technology could potentially be deployed in decommissioned mines worldwide. Under the new agreement, ABB will help Gravitricity to accelerate the technology towards commercial adoption.
“As the world generates more electricity from intermittent renewable energy sources, there is a growing need for technologies which can capture and store energy during periods of low demand and release it rapidly when required,” explains Gravitricity’s co-founder and executive chairman, Martin Wright. “Our GraviStore underground gravity energy storage uses the force of gravity to offer some of the best characteristics of lithium-ion batteries and pumped hydro storage – at low cost, and without the need for any rare-earth metals.
“We are already seeing significant interest from mine operators in Europe, India and Australia and this partnership with ABB – with decades of electrification and mine hoist system expertise – will help us accelerate our ambitious commercialisation plans. I am delighted we are working in tandem.”
Gravitricity will bring its specialist expertise in grid compliance and control systems, while ABB – which has an base of more than 1,000 hoists installed worldwide – will provide r&d, product development and engineering teams specialising in the design, engineering and operation of mine hoists, as well as associated mechanical, electrical and control technologies.
GraviStore raises and lowers heavy weights in underground shafts to store and release energy. Image: Gravitricity
They will work together on feasibility studies to understand the application of existing hoisting technology in gravity energy stores. ABB will also offer mining industry consultation and work to identify suitable sites and shafts for deploying GraviStore.
ABB says that the agreement is an important step in its ambition to develop its lifecycle service business by collaborating with companies providing adjacent and value-adding technologies.
“ABB has 130 years of history with mine hoists, since we first electrified one in Sweden in the 1890s, but this collaboration with Gravitricity shows how we can continue to diversify and adapt our technologies,” says Charles Bennett, global service manager for ABB Process Industries’ hoisting business. “We are eager to progress with our collaboration and explore the possibilities as we become part of the next generation of renewable energy storage systems and make use of mine shafts that are no longer in service.”
The decommissioning of mine shafts is a costly and time-consuming process. By repurposing disused mine shafts for energy storage, the shafts could fill a productive function for up to 50 years beyond their original lifetime, and mitigate decommissioning costs, while simultaneously creating new job opportunities and contributing to the green energy transition.
Earlier this year, Gravitricity raised £829,000 through crowdfunding to help develop in its technology.
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