Gravity energy storage brings life to Finnish mine

February 05, 2024

Underground energy storage innovator Gravitricity inks deal to transform disused mineshaft in central Finland into underground energy storage facility

Edinburgh-based Gravitricity has today detailed plans to turn Europe's deepest zinc and copper mine into the continent's first full-scale gravity-based energy store.

The deal with Finnish developer Callio Pyhäjärvi will see the Pyhäsalmi Mine's 530 metre deep auxiliary shaft host Gravitricity's energy storage technology, which uses heavy weights suspended by cables attached to winches to store and then rapidly release energy to the grid.

During periods when there is excess renewable power available - for example, on a windy day - the weight is winched to the top of the shaft. It can then be released when required, with the winches driving "generators" that can produce either a large burst of electricity quickly to help balance the grid or release it more slowly depending on demand. 

Once complete, the scheme is expected to deliver up to 2MW of storage capacity to the local electricity grid and provide balancing services to the Finnish network.

The full-scale prototype would become Europe's first GraviStore deployment, according to Gravitricity.

Martin Wright, executive chairman at the company, said the project would demonstrate at full scale how the company's technology can offer reliable long life energy storage that can capture and store power during periods of low demand and release it rapidly when required.

"This full-scale project will provide a pathway to other commercial projects and allow our solution to be embedded into mine decommissioning activities, offering a potential future for mines approaching the end of their original service life," he said. "It will also provide vital new low carbon jobs in an area which has suffered significantly from the end of traditional mining operations."  

The underground energy store would be one of a number of initiatives deployed at the former mine, alongside solar farms, mining technology testing facilities, and an underground 5G network.

Such schemes have been coordinated by Callio which was established by the local Pyhäjärvi community and site owners after the Pyhäsalmi mine closed in August 2022 following 60 years of operation.

Callio Pyhäjärvi's CEO, Henrik Kiviniemi, said the deal with Gravitricity would help strengthen the region's electricity grid and transform the energy market.

"It is also very attractive to take advantage of these opportunities for energy-intensive industry to be located here utilising also the good logistical location of Pyhäjärvi," he said. "Our industrial park can provide an excellent framework for electricity-intensive operators in the future, like Gravitricity, who can utilize the infrastructure and local know-how coming vacant from mining operations."

As well as its latest scheme in Finland, Gravitricity is currently advancing a number of other full-scale GraviStore projects, including a plan to transform state-owned mine infrastructure in Czechia into an energy store.

Moreover, in December ABB signed a memorandum of understanding with Gravitricity to explore how hoist technologies deployed in end of life mine shafts could enable the development of gravity-based energy storage systems.

The agreement will combine Gravitricity's energy storage technology with ABB's ability to work with the mining industry to identify suitable sites and shafts for the deployment of GraviStore sites.

The companies said GraviStore projects have the potential to provide more than 20MWh of energy storage capacity.