Facing the path and timetable of the net-zero transformation, some countries have begun to stop developing new coal mines or oil fields, and at the same time plan to close related facilities. However, after closing the mines, many employees will lose their jobs. Some scientists have suggested that if Turning mines into “gravity storage fields” can open up new jobs.
Gravity batteries are similar to pumped hydro storage, except that the medium changes from water to gravel. When there is excess power production, the heavy objects can be sent to the higher-lying “animal power bank”. When the power consumption increases, the heavy objects can be released. sent to the original position according to the terrain, then the turbine can be driven to generate electricity.
Basically, there are many versions of gravity batteries. The idea of the Austrian International Institute for Applied Systems Analysis (IIASA) in 2022 is to use the elevator of a high-rise building as another pipeline, and use the automatic trailer robot to put in or take out heavy objects as another. Energy storage medium; or mines can be used to create underground gravity energy storage (UGES), using sand and gravel as a medium.
The investment cost of UGES is about $1-10 per watt, and the power capacity cost is $2 per watt. The scientific team estimates that UGES has a global energy storage potential of 7-70 TWh, and most of them are located in China, India, Russia and other countries where there are many abandoned mines.
When a mine closes, it also lays off thousands of workers, UGES can create job vacancies, and the mining industry, once a highly polluting industry, is also transformed into energy storage systems, said Julian Hunt, a researcher at IIASA’s energy climate and environment project. The basic infrastructure already exists, and it is also connected to the grid, which greatly reduces costs and can also speed up the construction progress of UGES.
IIASA believes that by transporting sand into abandoned underground mines to store energy, UGES is an effective long-term energy storage solution, while also making good use of the millions of abandoned mines around the world.