Green power scheme could breath new life into former mining towns – Herald

Jody Harrison Reporter

THEY were thriving hubs of industry that fell on harder times when the
mines fell silent.

But now a green energy scheme which could revitalise Scotland’s mining
towns is ready to make the leap from the designers table and into reality.

Edinburgh-based Gravitricity has been awarded more than half a million
pounds to develop technology which harnesses the power of gravity to create
electricity.

The plan would see massive 2,000 tonne weights suspended over disused mine
shafts on an intricate pulley system, which could be dropped down at the
touch of button to create energy.

The developers say this would act like a battery for green energy and
provide a sudden jolt to the grid when other sources such as wind power
fell in capacity.

The firm are now on the look-out for locations to build a prototype, and
say that the industry could one day revitalise towns in Lanarkshire, Fife
and Midlothian which used to rely on mining with fresh jobs and economic
activity.

“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,” said Gravitricity managing director Charlie Blair

“So far there is a lot of focus on batteries, but our idea is quite
different. Gravitricity uses a heavy weight – up to 2000 tonnes – 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.”

“It’s a simple case of ‘What goes up, must come down,’” he added.

The project has been awarded a £650,000 grant from the Uk Government to
develop the technology, which is yet to be proven in the field.

However, the idea of using gravity to store energy is not new. Britain
already relies on a number of pumped storage hydro schemes, such as Ben
Cruachan, where water is pumped uphill to be released when required.

Mr Blair said: “The difference is we don’t need a mountain with a loch or
lake at the top, and we can react much faster.”

The biggest single cost of the project is drilling the hole for the weight,
and that is why the start-up is developing their technology utilising
existing mine shafts, both in the UK and also in South Africa.

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

The company plans to build and test a part-scale demonstration prototype
later this year, and they are currently short-listing a number of disused
mine shafts for the first full-scale working model in 2020.