Companies with abandoned underground mines could find a new purpose for them as a way to create and store energy.
In a study released by the International Institute for Applied Systems Analysis (IIASA), it was found that a new technique called “underground gravity energy storage” (UGES) could be an effective long-term energy storage solution while also making use of now-defunct mining sites.
UGES generates electricity when the price is high by lowering sand into an underground mine, converting the potential energy of the sand into electricity via regenerative braking.
It then lifts the sand from the mine to an upper reservoir to store energy when electricity is cheap.
The deeper and broader the mine shaft, the more power can be extracted from the plant, and the larger the mine, the higher the plant’s energy storage capacity.
UGES also has the potential to put jobs back on the market.
“When a mine closes, it lays off thousands of workers,” IIASA energy, climate, and environment program researcher and study lead author Julian Hunt said.
“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.
“Mines already have the basic infrastructure and are connected to the power grid, which significantly reduces the cost and facilitates the implementation of UGES plants.”
Research in the IIASA energy, climate and environment program and co-author of the study Behnam Zakeri said this was just one example of what the world could do to re-use abandoned mines.
“To decarbonise the economy, we need to rethink the energy system based on innovative solutions using existing resources,” he said.
“Turning abandoned mines into energy storage is one example of many solutions that exist around us, and we only need to change the way we deploy them.”