Sustainable Hydrogen Storage in Saline Aquifers: Potential, Challenges, and Future Pathways- A Review

Hydrogen is increasingly recognized as a cornerstone of the clean energy transition due to its high energy density and compatibility with renewable systems. Among various storage options, underground hydrogen storage (UHS) in saline aquifers offers significant potential for large-scale, long-term, and land efficient storage. This study evaluates the prospects and challenges of UHS in saline aquifers, focusing on geological suitability, technical barriers, and emerging innovations. Key issues, such as hydrogen loss through solubility and microbial consumption, geochemical interactions, and leakage risks, are examined using advanced geophysical imaging, reservoir modeling, and machine learning tools. Case studies from Germany, the U.S., and Australia provide real-world insights into storage integrity and performance. Results highlight the promise of saline aquifers, driven by favorable porosity, depth, and caprock conditions, while also acknowledging the need for microbial control, enhanced monitoring, and optimized injection strategies. The research underscores the importance of regulatory development, economic feasibility, and interdisciplinary innovation to enable safe, scalable hydrogen storage. By addressing these challenges, saline aquifers can play a pivotal role in stabilizing energy grids and achieving global decarbonization goals.