The Elements of Innovation Discovered

Turning European mines into batteries

Metal Tech News - May 13, 2024

Mining companies look to Gravitricity's gravity energy storage tech as anopportunity to extend usefulness of mine shafts after the ore is gone.

Energy storage is the lynchpin of a clean energy future that will rely on enormous quantities of zero-carbon electricity from intermittent sources such as wind and solar. After all, the billions of lightbulbs illuminating a city at night or millions of air conditioners keeping homes and businesses cool on a still summer day do not match well with optimal energy output from solar or wind.

Scotland-based Gravitricity has developed a patented technology called GraviStore that transforms underground mine shafts into gravity batteries that can bring equilibrium to electrical grids that are increasingly reliant on wind and solar.


Gravitricity Executive Chairman Martin Wright.

"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," said Gravitricity Executive Chairman Martin Wright.

Operators of deep underground mines in Slovenia, Germany, the Czech Republic, and Finland are looking at GraviStore as an opportunity to extend the usefulness of their operations as ore production winds down.

"Gravity energy storage offers a powerful green opportunity to mine operators looking to extend a mine's life beyond the extraction of materials," said Wright. "As well as being a genuine alternative to decommissioning, new underground energy storage schemes can provide economic and employment opportunities in communities where traditional jobs are in decline."

GraviStore advantages

Fundamentally, GraviStore is an energy storage system that siphons excess renewable energy off the grid to power winches that lift heavy weights up vertical mine shafts. When extra power is needed, the weight is lowered, and the winches turn into generators that feed the stored energy back to the electrical grid.

A 20-megawatt GraviStore system could store enough energy to power 26,000 homes for two hours. While this stored energy would typically be delivered as a supplement to other sources over a much longer duration, the gravity battery is also able to rapidly deliver a burst of energy to the grid if needed.

"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," said Wright.

Another advantage of GraviStore is its energy storage capacity does not diminish over time.

Gravitricity has already proven the viability of GraviStore with an above-ground 250-kilowatt demonstrator in Scotland, where the company successfully raised and lowered two 25-metric-ton weights to generate full power and verify the system's speed of response.

The 12-meter-high test rig proved the system can go from zero to full power in less than a second – which can be extremely valuable for maintaining optimum electrical grid frequency and as a source of back-up power – as well as continuously vary power output dependent on demand.


Gravitricity began working with Dutch lifting specialist Huisman in 2018 to develop the 250-kw prototype and more recently partnered with ABB to explore how that company's world-leading hoist expertise and technologies can accelerate the development and implementation of gravity energy storage systems in former mines.

"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," said Charles Bennett, global service manager of business line hoisting at ABB Process Industries.

In addition to working with Gravitricity on feasibility studies to understand the application of existing hoisting technology for energy storage, ABB is providing mining industry consultation and working to identify suitable sites and shafts for the deployment of GraviStore.

European mining interest

Once all the ore is extracted from an underground mine, the company that carried out the mining is responsible for the costly and time-consuming process of decommissioning the mine shafts.

The repurposing of mine shafts as gravity storage systems for renewable energy can help mitigate those costs by providing a new green energy use for the mine that creates new job opportunities for decades.

The win-win situation of lowering postproduction mine costs and making a positive contribution to the clean energy transition has drawn interest from several mining companies with operations in Europe.


GraviStore siphons excess electricity off the grid to power winches that lift heavy weights up a vertical mine shaft. When extra power is needed, the winches become generators that turn the stored gravity energy back into electricity.

Current projects considering GraviStore installations are:

The government-owned Velenje lignite coal mine in northeastern Slovenia.

The past-producing Darkov coal mine near the Czech Republic city of Karviná.

The past-producing Grube Teutschenthal rock salt and potash mine in Germany.

The past-producing Pyhäsalmi Mine – Europe's deepest zinc and copper mine – in northern Finland.

Gravitricity engineers have already visited Velenje to assess the technical feasibility of installing systems in two shafts, one of which is a ventilation shaft that may become available for a potential pilot project next year.

"The Velenje mine could be very well suited to future energy storage schemes as the operational shafts are both deep and in excellent condition," said Nigel Voaden, engineering project manager at Gravitricity.

Studies are also ongoing for near-term pilot projects at the Darvok, Grube Teutschenthal, and Pyhäsalmi mines.

"Our work with mine operators is underlining the interest in our technology, and we are in dialogue with both mine owners and public sector organizations to turn these studies into operational plans," said Wright.

Author Bio

Shane Lasley, Metal Tech News

Author photo

With more than 16 years of covering mining, Shane is renowned for his insights and and in-depth analysis of mining, mineral exploration and technology metals.


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