Abandoned and orphaned oil and gas wells pose significant public health problems and threats to the environment. In general, abandoned wells are unproductive wells with an identifiable owner, whereas orphaned wells are unproductive wells without an identifiable owner. An idle oil well refers to a well that is temporarily not producing oil or gas but has the potential to be brought back into production. It might be shut down for maintenance, repairs, or due to economic factors such as fluctuating oil prices. There is a growing narrative that the existing infrastructure of idle wells could be repurposed for use in the energy transition having social and environmental benefits.

Once an idle oil well is plugged with the Geo2Watts™ proprietary heat exchanger, this effectively converts it into a Thermal Energy Storage (TES) system. Solar thermal collectors are used as the source of renewable heat, although heat pumps and resistance heaters can also be used to heat pressurized water up to 175°C. This heated water is then circulated throughout the TES with a closed-loop heat exchanger comprised of a unique combination of thermal conducting and insulating materials.

During electricity production, the pressurized water flows through the heat exchanger within the TES, which is then transferred to the evaporator/boiler of an Organic Rankine Cycle (ORC) power plant, driving the power cycle to produce electricity. The optimized design of the novel TES and its heat exchanger, combined with the ORC power plant and solar collector field, form the critical components of the closed-loop system named the Borehole Battery™, which is a patent-pending technology.

California has over 37,000 idle oil wells and the Permian Basin has approximately 100,000 idle oil wells. Repurposing these wells could provide a valuable source of clean, dispatchable electricity to meet rising power demands and offset the intermittency of renewables, rather than letting them contribute to pollution. Repurposing idle oil wells provides a strategic alternative to plugging and offers owners a future source of revenue from underperforming wells that are nearing the end of their life cycle.

Implementing the Borehole Battery™ on a large scale would significantly reduce the number of idle wells. This approach involves sealing producing zones to prevent methane leakage and repurposing existing infrastructure. Additionally, it would enhance energy storage capacity by providing on-demand, zero-emission, dispatchable electricity during peak hours.