Abandoned Coal Mines Are Becoming the Batteries of the Future

From Europe to North America, an energy revolution is breathing new life into empty, long-forgotten coal mine shafts — by repurposing them into places to store renewable energy.

Using “gravity batteries,” these underground facilities aim to tackle one of renewable energy’s greatest challenges: storage. The method is simple: Excess renewable energy is used to power winches that lift heavy weights — such as containers filled with sand or rock — up the mine shaft. When additional energy is needed, these weights are released, generating power as they descend.