In the quest for a greener energy future, the intermittent nature of renewable sources like wind and solar power poses a significant challenge to grid stability. Enter compressed air energy storage (CAES), a technology that could be the linchpin in balancing the grid’s fluctuating energy supply. A recent study published in *Modern Geology and Exploration*, led by Wen Jiang of the Geological Survey Institute of Hunan Province, delves into the geological evaluation of underground gas storage (UGS) facilities for CAES, offering insights that could shape the future of energy storage.
The study systematically reviews recent domestic and international literature to assess the current state of CAES technology, focusing on three types of UGS facilities: soft rock caverns, porous mediums, and hard rock caverns. Each type presents unique advantages and challenges. Soft rock caverns, such as salt rocks or abandoned mines, boast mature techniques but come with high costs. “The evaluation of these caverns should prioritize their stability and long-term sealing,” Jiang notes.
Porous mediums, like sandstones or abandoned hydrocarbon reservoirs, offer large reserves but face severe gas control difficulties. “It’s crucial to consider trap conditions, reservoir physical properties, and fault sealing comprehensively,” Jiang explains. Hard rock caverns, including basalts or granites, are noted for their strong stability but also incur high construction costs. Optimizing fracture control and composite lining technology is key here.
Despite significant progress in siting and evaluating UGS facilities, the research highlights several challenges. Salt caverns are highly dependent on specific conditions, abandoned coal mines and hard rock caverns face economic limitations, and the heterogeneity of porous mediums affects gas storage efficiency. Additionally, the evaluation of geological resource potential is hindered by data accuracy and simplified assumptions, while reservoir simulations often overlook multi-field coupling effects.
Looking ahead, Jiang suggests that future research should focus on fine-scale studies of pore structure and caprock in porous reservoirs. Integrating 3D seismic technology to construct high-precision geological models and developing heat-water-force multi-field coupling models are also recommended. “Verifying reservoir behavior under dynamic conditions through experiments will be crucial,” Jiang adds.
The implications of this research are profound for the energy sector. As the world moves towards achieving peak carbon dioxide emissions and carbon neutrality, the stable operation of the green power grid becomes paramount. CAES technology, with its large capacity and low cost, is poised to play a pivotal role. By addressing the current technical bottlenecks and advancing the geological evaluation of UGS facilities, this study paves the way for more efficient and reliable energy storage solutions.
In essence, Jiang’s work not only provides a theoretical and technical reference for large-scale applications of UGS facilities for CAES under varying geological conditions but also underscores the importance of interdisciplinary collaboration in driving innovation in the energy sector. As the world grapples with the complexities of transitioning to renewable energy, such research offers a beacon of hope and a roadmap for a more stable and sustainable energy future.