Recent Progress in Underground Hydrogen Storage

With the global population anticipated to reach 9.9 billion by 2050 and rapid industrialization and economic growth, global energy demand is projected to increase by nearly 50%. Fossil fuels meet 80% of this demand, resulting in considerable greenhouse gas emissions and environmental challenges. Hydrogen (H2) offers a promising alternative due to its potential for clean combustion and integration into renewable energy systems. Underground H2 storage (UHS) enables long-term, large-scale storage to achieve equilibrium between seasonal supply and demand. This review synthesizes recent advancements in UHS, highlighting progress and persistent challenges. The review explores the complex mechanisms of H2 trapping and its implications for storage security and efficiency. The challenges these mechanisms present compared to other gases are discussed, emphasizing the unique properties of H2. The exploration covers interactions between H2 and geological formations, focusing on the wettability, interfacial tension, and sorption characteristics of rock–H2–brine systems. Advanced experimental methods are evaluated alongside the effects of critical parameters, including temperature, pressure, salinity, and organic contaminants. Findings from innovative imaging, core-flooding techniques, and computational methods (e.g., molecular dynamics simulations and machine learning) are incorporated. These approaches are vital for understanding H2 behavior in subsurface environments and developing robust, efficient storage solutions. This review offers a comprehensive update on recent progress, identifying and addressing the remaining gaps in UHS research. This work also highlights the significance of interdisciplinary research and technological innovation in overcoming these challenges. By providing insight into recent theoretical research, practical applications, and technological development, the findings support the successful incorporation of H2 into the global energy infrastructure, contributing to implementing a sustainable H2 economy successfully and fostering energy security and environmental protection for future generations.