- Underground Gravity Energy Storage involves dropping sand down a mine and harnessing the kinetic energy generated.
- IIASA believes 70TWh of energy could be generated globally using UGES.
- Power generated using UGES could be concentrated around China, India, Russia and the US.
A study led by the International Institute for Applied Systems Analysis (IIASA) published earlier this month proposes the use of old and abandoned mines for energy generation.
The study revolved around a new way to store energy through something called Underground Gravity Energy Storage (UGES).
“UGES generates electricity when the price is high by lowering sand into an underground mine and converting the potential energy of the sand into electricity via regenerative braking and then lifting the sand from the mine to an upper reservoir using electric motors to store energy when electricity is cheap. The main components of UGES are the shaft, motor/generator, upper and lower storage sites, and mining equipment. The deeper and broader the mineshaft, the more power can be extracted from the plant, and the larger the mine, the higher the plant’s energy storage capacity,” writes a team from IIASA.
While the use of sand in a mine is new, the concept of using gravity to harness kinetic energy isn’t.
The Dinorwig Power Station in Wales makes use of water to drive turbines which generate energy for the UK when demand peaks.
The idea from IIASA also highlights how UGES could also help those who work in mines from being let go when the mine is eventually shuttered.
“When a mine closes, it lays off thousands of workers. This devastates communities that rely only on the mine for their economic output. UGES would create a few vacancies as the mine would provide energy storage services after it stops operations,” explains lead author of the study and Energy, CLimate and Environment research at IIASA, Julian Hunt.
In addition, connecting mines to wider electricity supply grids is less costly as many are already connected.
The study estimates that generating electricity in this manner would cost $2 per kilowatt and has the potential to generate as much as 70TWh globally. The countries with the most potential to benefit from this solution include the US, and South African BRICS allies, China, Russia and India.
With South Africa expecting at least 24 months of unabated loadshedding, perhaps government and Eskom can explore how UGES could be deployed in South Africa. With approximately 6 000 abandoned mines scattered throughout the country, this could be a decent, sustainable path towards a Just Energy Transition.
[Image – CC 0 Pixabay]
