Gold rush: Gravitricity secures £300,000 to scope out South African mines for energy storage potential

  • Apr 02, 2020
  • Business Green

UK tech start-up Gravitricity has unveiled plans to explore the energy storage potential of South Africa's former mine shafts, thanks to a £300,000 funding boost from government agency Innovate UK.

The company's energy storage technology works by raising multiple heavy weights, weighing up to 21,000 tonnes in total, in a deep shaft and releasing them again to power a generator when the energy is required.

It said its system was ideally suited to South Africa where numerous mine shafts are situated, with some as deep as 3km, adding that it could help balance the grid in a country currently facing an "energy crisis" that has resulted in frequent blackouts.

"The country has ambitious plans to develop more renewable energy, but at the same time there is a lack of supply and robust grid infrastructure to carry power to factories and people's homes - particularly at peak times," explained Gravitricity's managing director Charlie Blair. "Our technology uses repurposed mine shafts to store excess energy and then release it when required - either in very rapid, short bursts or over a long period of time. This takes pressure off the grid and helps smooth supply at vital times. And because South African mines are so deep, this means we can store even greater quantities of power."

The £300,000 funding from Innovate UK comes in addition to the £650,000 grant the firm received from the government agency two years ago.

Previous research carried out by Imperial Collage London on behalf of Gravitricity found its system had the potential to store energy at half the lifetime cost of lithium ion batteries, and the firm is currently developing plans to install the technology in repurposed mineshafts across Europe.

Later this year, the company plans to build a 250kW scale prototype of its technology in collaboration with Dutch winch specialists Huisman.

In South Africa, the firm has teamed up with energy consultancy RESA and specialist consultants Caelulum to scope out suitable sites, although their field trips have had to be delayed until next year due to the current coronavirus pandemic.

Once the field trip research has been completed, however, the firm plans to assess the commercial potential of a range of sites, select suppliers, and make a final site selection where it can deploy the technology.

"The South African electricity market is in crisis," said Melani De Lima, research analyst at RESA. "Since 2008 the country has been faced with intermittent periods of load shedding. Even though the renewable energy technologies brought online by the country's Renewable Energy Independent Power Producers Procurement Programme [REIPPP] provide a cleaner, greener solution to our country's electricity supply problems, it does not solve the problem of intermittent electricity supply to the South African grid."

"Gravitricity offers a solution that addresses the problem of intermittency by storing large amounts of energy, and also addresses grid imbalances through super-fast response times," she added.

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