Natural hydrogen migration and accumulation as a blueprint for enhanced underground hydrogen storage

Underground hydrogen storage (UHS) is emerging as a key technology to overcome renewable energy intermittency and enable the low-carbon transition. Yet, low recovery rates and hydrogen losses remain key obstacles, limiting progress in reservoir optimization, storage capacity, and injection–production management. To address these challenges, we first identify the primary pathways of hydrogen loss, categorized as trap loss and consumption loss. We then examine the occurrence, migration, consumption, and accumulation of natural hydrogen in geological formations, providing insights that form the theoretical basis for optimizing UHS strategies. The concept of enhanced underground hydrogen storage (EUHS) is proposed and defined as the pre-construction strategy to minimize losses and improve recovery by optimizing reservoir types and conditions. Two novel EUHS strategies within the immature natural hydrogen system and fractured tight reservoirs are proposed and evaluated using a scoring framework based on safety, capacity, and efficiency. Immature hydrogen reservoirs provide dual benefits by improving returns on natural hydrogen exploration and reducing hydrogen losses, thereby achieving the highest score. Fracture networks in tight formations combine the stability of porous reservoirs with the conductivity of salt caverns, providing a balanced storage option. Moderate H₂–rock contact reduces trapping and loss. Considering microbial activity, adsorption, and solubility, the optimal storage depth is 800∼2500 m (40∼100 °C), while higher temperatures risk H₂S formation. In water-rich environments, this depth is restricted to 800–1000 m to limit hydrogen dissolution. This study bridges natural and artificial hydrogen storage, creating mutual benefits and advancing hydrogen energy development.