A research team from Pennsylvania State University in the United States has proposed an innovative energy storage solution: transforming depleted oil and gas wells into geothermal-assisted compressed air energy storage systems. This method is expected to enhance the grid's ability to absorb renewable energy while reducing the implementation costs of existing storage technologies.

The study, published in the Journal of Energy Storage, demonstrates that utilizing approximately 3.9 million abandoned oil and gas wells across the United States for compressed air energy storage could achieve a 9.5% improvement in system efficiency compared to conventional approaches. The technology involves injecting compressed air into underground wells for storage during periods of low electricity demand, then releasing it during peak demand to drive generators, while leveraging natural underground geothermal resources to boost energy conversion efficiency.

Project lead Professor Arash·Dahi·Taleghani stated: "This efficiency improvement could transform the economic viability of compressed-air energy storage projects. By utilizing existing oil and gas well infrastructure, we can significantly reduce upfront investments while achieving dual goals of environmental remediation and energy transition."

Through numerical simulations, the research team confirmed that natural geothermal heat in underground rock formations can effectively increase the temperature and pressure of stored air, thereby enhancing the system's power generation capacity. Taleghani added: "After integrating geothermal components, we obtained encouraging data. This retrofit solution not only avoids the high costs of drilling new wells but also prevents methane leaks by sealing wellheads, improving local ecosystems."

This solution provides a new pathway to address the intermittency of renewable energy sources. When wind or solar power supply is interrupted, the stored compressed air can promptly supplement grid demand. The researchers noted that this technology could also create new job opportunities in traditional energy-producing regions, promoting sustainable regional economic development.