In the pursuit of a greener energy future, researchers are turning to innovative technologies to store and manage renewable energy efficiently. One such technology, compressed air energy storage (CAES), is gaining traction as a solution to the intermittent nature of wind and solar power. A recent study published in *Meitian dizhi yu kantan* (Modern Geology and Prospecting) sheds light on the geological evaluation of underground gas storage (UGS) facilities, offering insights that could revolutionize the energy sector.
The study, led by Wen Jiang from the Geological Survey Institute of Hunan Province in Changsha, China, systematically reviews the current state of CAES technology and evaluates the applicability, performance, and technical bottlenecks of three types of UGS facilities: soft rock caverns, porous mediums, and hard rock caverns. “CAES technology is crucial for the stable operation of the green power grid due to its large capacity and low cost,” Jiang explains. “However, each type of UGS facility presents unique challenges and opportunities.”
Soft rock caverns, such as salt rocks or abandoned mines, are noted for their mature techniques but come with high costs. The evaluation of these caverns focuses on their stability and long-term sealing. Porous mediums, like sandstones or abandoned hydrocarbon reservoirs, offer large reserves but pose significant challenges in gas control. “The heterogeneity of porous mediums affects gas storage efficiency, making it essential to consider trap conditions, reservoir physical properties, and fault sealing,” Jiang adds.
Hard rock caverns, including basalts or granites, are praised for their stability but are hampered by high construction costs. Optimizing fracture control and composite lining technology is critical for these facilities. The study highlights the progress made in siting and evaluating UGS facilities, assessing geological resource potential, and modeling UGS. However, it also identifies key challenges, such as the economic limitations of abandoned coal mines and hard rock caverns, the impact of heterogeneity on porous mediums, and the need for more accurate data and comprehensive reservoir simulations.
Looking ahead, the study suggests that future research should focus on fine-scale research of pore structure and caprock of porous reservoirs, integrating 3D seismic technology to construct high-precision geological models. Developing heat-water-force multi-field coupling models and verifying reservoir behavior under dynamic conditions through experiments are also recommended.
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 need for reliable and efficient energy storage solutions becomes increasingly urgent. CAES technology, with its potential for large-scale applications under varying geological conditions, could play a pivotal role in stabilizing the green power grid and ensuring a sustainable energy future.
Jiang’s work not only provides a theoretical and technical reference for the large-scale application of UGS facilities for CAES but also underscores the importance of continued innovation and research in this field. As the energy sector navigates the complexities of renewable energy integration, the insights from this study could guide the development of more efficient and cost-effective energy storage solutions, ultimately shaping the future of the energy landscape.