A comprehensive review of process risk management in compressed hydrogen storage for refuelling stations

This study comprehensively reviews the risk assessment on hydrogen refuelling stations (HRS), with a focus on identifying uncertainties in current methodologies and critical gaps in safety protocols. The review is based on a systematic analysis of peer-reviewed journal articles, major accident investigation reports, industrial safety databases, and international standards published over the past two decades. Key risk assessment approaches, including hazard identification techniques, quantitative risk assessment (QRA), fault and event tree analysis, and consequence modelling, are critically examined. The paper evaluates both empirical and computational fluid dynamics (CFD)-based models used to predict hydrogen dispersion, jet fires, explosions, and associated physical effects, highlighting their applicability, limitations, and uncertainties. Vulnerability and probit models commonly adopted in consequence analysis are compared, with particular attention to inconsistencies in fatality and damage predictions. The review highlights major deficiencies of HRS risk assessment, including limited hydrogen-specific failure data, simplified treatment of ignition probability, limited validation of consequence models under high-pressure release conditions, and inconsistencies among international safety standards and regulatory criteria. The paper provides recommendations to improve hydrogen risk management frameworks for future HRS, including the development of more robust data-driven likelihood models and better integration of advanced numerical tools into QRA.