Abandoned, orphaned, and idle oil and gas wells represent a growing environmental and public health challenge. Abandoned wells are non-producing wells with an identifiable owner, while orphaned wells lack a responsible owner altogether. Idle wells—which are temporarily shut in due to maintenance, repairs, or unfavorable economics—are no longer productive but retain valuable subsurface infrastructure. Increasingly, these idle wells are being recognized as an opportunity to support the energy transition by repurposing existing assets in ways that deliver both environmental and social benefits.

Geo2Watts’ Borehole Battery™ is a patent-pending technology that transforms idle oil and gas wells into long-duration energy storage (LDES) assets while permanently plugging them in full compliance with regulatory requirements. Rather than simply abandoning these wells, Geo2Watts converts them into grid-connected thermal energy storage systems that can deliver clean, dispatchable electricity.

Once an idle well is permanently plugged in accordance with mandated protocols, a closed-loop heat-exchange system is installed within the wellbore. Using a proprietary combination of thermally conductive and insulating materials, the well is effectively converted into a Thermal Energy Storage (TES) system. The Borehole Battery™ is charged using low-cost or surplus renewable electricity via a Reversible High-Temperature Heat Pump (RHTHP), which heats pressurized water to approximately 200 °C and circulates it through the underground TES.

During discharge, the stored thermal energy is transferred back through the heat exchanger to the RHTHP, where it is converted directly into AC electricity. The integrated design of the TES, proprietary thermal materials, and high-performance heat exchanger—combined with the RHTHP—enables the Borehole Battery™ to deliver clean, dispatchable, and distributed power without the need for inverters and, in brownfield deployments, without new transformers.

The scale of this opportunity is significant. California has approximately 50,000 idle oil wells, the Permian Basin contains more than 100,000 idle wells and according to the EIA, there are about 1 million idle and underperforming wells in the United States. Repurposing even a fraction of these assets could provide gigawatts of long-duration, behind-the-meter energy storage—helping meet rising electricity demand, smoothing renewable intermittency, and reducing reliance on fossil-fuel peaker plants.

By repurposing idle wells rather than abandoning them, the Borehole Battery™ offers a strategic alternative to traditional plugging. It mitigates environmental risk, accelerates deployment by leveraging existing permitted infrastructure, and creates a new revenue pathway for well owners from assets nearing the end of their productive life—turning legacy oil and gas infrastructure into a cornerstone of the clean energy transition.