Across the United States, a staggering half a million abandoned coal mines remain as reminders of a bygone era. These sites, largely left untouched since their closure in the 1970s, pose significant risks to public health, safety, and the environment. However, an innovative approach could transform these liabilities into assets, aiding the renewable energy movement.
Researchers at Oak Ridge National Laboratory (ORNL) have made significant strides in converting these derelict coal mines into energy storage facilities. By employing advanced hydrodynamic and chemical modeling, they have demonstrated the potential of these sites to function as pumped hydro storage units, which can support the power grid by providing long-term energy storage solutions.
The implications of this development are substantial. Not only would it address the safety hazards associated with abandoned mines—such as open mine shafts and contaminated water—but it would also revitalize these areas. According to a report from Mining.com, these hazards threaten infrastructure and homes, prompting the Trump administration to allocate $725 million in 2025 to address these issues.
Beyond environmental and safety benefits, repurposing coal mines for energy storage could offer economic revitalization for former coal mining regions. With the coal industry in decline—its contribution to the national energy grid expected to fall from 45% in 2010 to below 1% by 2035—these communities face economic challenges. The National Bureau of Economic Research highlights the potential for “a steep fall in economic activity, shrinking revenue, and a dislocated workforce” in these areas as a result of the industry’s downturn.
Transforming these mines into “water batteries” could provide stability to the U.S. power grids, which are under pressure from rising energy demands due to the proliferation of data centers supporting the AI industry boom. As noted, the aging power infrastructure is being pushed to its limits, necessitating advancements in energy storage to ensure energy security and adherence to clean energy goals.
Current energy storage solutions, predominantly reliant on lithium-ion batteries, are limited to a few hours of storage, which is insufficient for stabilizing energy supply and demand over longer periods. Pumped hydro, therefore, emerges as a leading technology in the global race for efficient and sustainable long-term energy storage solutions.
The endeavor to use disused coal mines for pumped hydro storage is not without its challenges, given the complex and reactive environments within these sites. However, ORNL’s sophisticated modeling tools are designed to help industry stakeholders navigate these complexities, as explained by Galen Fader of ORNL. These tools provide insights into the movement of water and its chemical interactions, aiding in the design and operational decisions for such facilities.
Original Story at oilprice.com