Green mine plan could bring jobs

Gravitricity Managing Director Charlie Blair at  National Mining Museum Scotland, Newtongrange.
Gravitricity Managing Director Charlie Blair at National Mining Museum Scotland, Newtongrange.

Former mining communities including in Midlothian could find a new lease of life – with old mine shafts turned into hi-tech green energy stores.

This is the plan of Gravitricity, which has just received a £650,000 grant from Innovate UK, the UK Government’s innovation agency, to harness the power of gravity to store renewable energy.

Gravitricity plant visualised within rural edge landscape setting using 3D software.

Gravitricity plant visualised within rural edge landscape setting using 3D software.

The company’s technology uses a weight up to 2000 tonnes suspended in mine shafts to capture green power, and then release it in seconds.

No specific site has been identified in Midlothian yet, but the Edinburgh-based company said it would be interested to hear from any site that would be suitable.

The government funds will enable Gravitricity to start building a scale demonstrator later this year, and find a site to install a full-scale prototype by 2020. It is now on the look-out for investors, including those who can bring mining experience to the team, and suitable mine shafts to trial their technology.

And once Gravitrcity has proven the technology in old mines, it then plans to sink new shafts to store energy wherever it is required.

“As we rely more and more on renewable energy, there is an increasing need to find ways to store that energy – so we can produce quick bursts of power exactly when it is needed,” explained managing director Charlie Blair.

“So far there is a lot of focus on batteries, but our idea is quite different. 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 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 degradation or reduction in performance.

Blair added that the biggest single cost is the hole, and that is why the start-up is developing its technology utilising existing mine shafts in the UK and South Africa.

The start-up plans to build models from 1 to 20MW, and estimates each ‘Gravitricity Energy Storage System’ will last up to 50 years.

Later this year it will build and test a part-scale demonstrator, and is currently short-listing a number of disused mine shafts for a full-scale working prototype in 2019/20.