Under this novel system, weights are winched above mine shafts using green power generated on sunny or windy days, ready to be dropped to generate power when renewable output slumps or the grid needs power to “balance” its output. Madeleine Cuff discusses the technology in an article on the inews website.
Mine shafts set to become energy storage hubs thanks to British invention
A novel energy storage technology, which involves suspending heavy weights above deep mine shafts, is a “serious contender” in the global energy storage market, its creators have said.
Gravitricity told i its demonstrator project built in Edinburgh earlier this year has proved a success, with the team raising and lowering two 25-tonne weights to generate power.
“These tests confirm our modelling and show that gravity energy storage is a serious contender in the global energy storage market,” said company managing director Charlie Blair.
To meet climate goals the UK needs to get most of its electricity from wind and solar power. But maintaining a steady supply of power to homes and businesses when the wind doesn’t blow or the sun doesn’t shine will require large-scale energy storage.
Using gravity to store power could be a cheaper, greener way of storing energy for the grid compared to lithium-ion batteries, Gravitricity believes. It would also save raw materials like lithium, nickel, and cobalt, which are also needed for batteries in electric cars.
Under Gravitricity’s system, weights are winched above mine shafts using green power generated on sunny or windy days, ready to be dropped to generate power when renewable output slumps or the grid needs power to “balance” its output.
Unlike batteries, which have a relatively short lifespan, gravity storage could work for more than 25 years with no loss of output. Studies suggest it would also be 50 per cent cheaper than using batteries over its lifetime.
Gravitricity’s Edinburgh demonstrator raised and lowered weights above ground. The start-up now plans to start fundraising for a full-scale project that will see 500-tonne weights dropped down into mine shafts 750 metres deep. Each weight would produce about 1MWh of energy storage capacity, enough to provide power to hundreds of homes for an hour, and would cost £8 to £16m to build.
The UK, Poland, South Africa, and the Czech Republic are being considered as locations, with plans for the new site to be up and running by 2024.
“In the UK we are considering brownfield sites and are also looking at the potential to sink a new-purpose built shaft in partnership with a major British civil engineering firm,” Mr Blair said. Eventually there could be “thousands” of mine shafts used as storage sites around the world, he added.