Abandoned Mines May Be Repurposed as Gravity-Powered Batteries

A gravity battery generates electricity by releasing a heavy load, converting potential energy into power when grid demand is high. When surplus energy is available, the system lifts the load back up for future use.

A common example is pumped-storage hydroelectric systems, where water flows downhill to generate power and is pumped back up when there’s excess energy.

In 2022, researchers at Austria’s IIASA proposed using regenerative braking in high-rise elevators to generate electricity as weighted loads move between floors, managed by autonomous robots.

Building on this, they introduced the Underground Gravity Energy Storage (UGES) system, which uses abandoned mine shafts to store energy. Elevators in the shafts would raise and lower sand-filled containers, generating electricity through regenerative braking.

To optimize efficiency, the system would transport sand to the bottom of the shaft when energy demand is high. Over time, as the lower storage area fills up, surplus grid energy would be used to bring sand back to the surface. Electric conveyor belts and dump trucks would handle the loading and unloading process.

A Promising Global Energy Solution

Researchers estimate that UGES could store between 7 and 70 terawatt-hours (TWh) of energy worldwide. Countries with numerous abandoned mines—such as China, India, Russia, and the US—would be prime locations for these storage plants.

Beyond energy storage, UGES could also create new jobs in mining communities affected by closures. “When a mine shuts down, thousands of workers lose their jobs. UGES could provide employment opportunities as these mines transition to energy storage facilities,” explained Julian Hunt, IIASA’s lead researcher on the study. “Since mines already have essential infrastructure and power grid connections, the cost of implementing UGES is significantly lower.”

Since this study was first published, Hunt has received interest from various stakeholders, including three mine owners, two investors (one of whom is a YouTube executive), and three project developers. Additionally, he is developing new gravity-based energy storage concepts and plans to publish more research later in 2025.

Read Original Article: New Atlas

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