MechChem Africa March-April 2023

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Gravitricity and the state-owned enterprise, DIAMO, in the Czech Republic have signed a memorandum of understanding committing to the transformation of the Darkov deep coal mine into an underground energy store. Green future for former coal mines T he first full scale 4.0 MW, 2 MWh gravity-based energy storage scheme is set to promote a new fu ture for mining communities as the onstrated a scale version of its technology – built in partnership with Dutch winch specialist Huisman – and now plans to build full-scale schemes in the UK and worldwide. Future multi-weight systems could have a capacity of 25 MWh or more.

for mines and for our experts, who can try working on new projects and cooperation with a foreign entity. We have a lot of work ahead of us, we need to check all aspects and risks related to operation of the mine.” At Darkov, DIAMO is also planning to build a photovoltaic power plant and is con sidering the production of green hydrogen. The site will be home to an experimental greenhouse project – called EDEN Silesia – managed by the Silesian University. Gravitricity technology Gravitricity uses heavy weights – totalling up to 12 000 t – suspended in a deep shaft by cables attached to winches. When there is excess electricity, for example on a windy day, the weight is winched to the top of the shaft ready to generate power. This weight can then be released when required – in less than a second – and the winches become generators, producing either a large burst of electricity quickly, or releasing it more slowly, depending on what is needed. Unlike batteries, the Gravitricity system can operate for decades without any reduction in performance. The idea of using gravity to store energy is not new. Europe already relies on several pumped storage hydro schemes, mostly in mountainous regions in Switzerland, Austria and Germany, where water is pumped uphill to be released when required. Worldwide, Gravitricity estimates there are around 14 000 mines that could be suit able for gravity energy storage using this technology. q

world moves towards net zero. Underground energy storage specialist Gravitricity has signed a memorandum of understanding with DIAMO, the Czech state enterprise charged with mitigating the consequences of uranium ore and coal mining in the republic. The memorandum will see the partners work together to seek EU funds to trans form the former Darkov deep mine into a massive energy store – which could be a pathfinder for projects Europe-wide. At a formal signing ceremony at the British Embassy in Prague, the two parties committed to work in tandem to seek funds to turn the decommissioned mine into an energy store capable of powering more than 16 000 homes. Gravitricity also signed a memorandum with VSB Technical University of Ostrava, whose specialist mining expertise will sup port the implementation of Gravitricity’s technology into the existing mine. The Darkov mine is located in the coal-rich Moravian-Silesian region of the Czech Republic, near the city of Karviná. Construction started in 1972, to access thick seams of coal more than 700 m below the surface and, at its peak, it employed around 4 000 people. Gravitricity plans to store energy by lowering and raising a single massive weight suspended in the Darkov mine shaft. The Edinburgh-based firm has already dem

Speaking at the ceremony, Gravitricity Managing Director, Charlie Blair said: “A low carbon world will require vast amounts of energy storage, and at Gravitricity we have developed a long-life energy storage technology, which can delivery super-fast energy and offers some of the best charac teristics of lithium batteries and pumped hydro storage. “We hope our collaboration with DIAMO will allow us to demonstrate this technology at scale and offer a potential future for coal mines that are approaching the end of their original service life.” The British Ambassador to the Czech Republic Matt Field added: “It is a great honour to host this Memorandum of Understanding signing ceremony. We truly appreciate that Gravitricity, DIAMO and the Technical University of Ostrava plan to cooperate on Gravitricity’s first prototype project. It would be the first full-scale instal lation of this renewable energy technology, a project that is unique, transformative, and green.” Talking on behalf of DIAMO, Ludvík Kašpar said: “Our main task is to provide the liquidation of mines, but at the same time we are looking for new uses for the mine sites according to the needs of the region. The Gravitricity project is an opportunity

Gravitricity uses heavy weights suspended in a deep shaft by cables attached to winches. When there is excess electricity, the weight is winched to the top of the shaft ready to generate power by dropping the weight.

44 ¦ MechChem Africa • March-April 2023