March 5, 2026 - Oak Ridge National Laboratory has announced it is working to transform abandoned coal mines to ensure access to safe and reliable energy.

ORNL said the mines will be transformed into underground pumped storage hydropower (PSH), which could help strengthen the country’s electric grid.

PSH requires geographic features, such as hills and mountains, to create a natural height differential between two reservoirs, according to ORNL.

By using existing mine infrastructure, ORNL said underground PSH could recreate and utilize the height differential in more regions, expand the geographic reach of traditional PSH and reduce construction costs.

“Underground PSH is an exciting opportunity, but we have to overcome challenges like chemical erosion and structural stability,” ORNL Senior Researcher Thien Nguyen said. “Our modeling tools will help industry partners evaluate these risks and make informed decisions about facility design, construction and operations at specific locations of interest.”