Quantitative Risk Assessment of Hydrogen Releases in a Hydrogen Fueling Station with Liquid Hydrogen Storage

Quantitative Risk Assessments (QRA) is an important tool for enabling safe deployment of hydrogen technologies and is increasingly embedded in the permitting process. Following the framework developed in our companion paper, we conducted a detailed QRA on the uncontrolled releases from a high-capacity hydrogen fueling station with liquid hydrogen (LH2) storage. We characterized gaseous and liquid hydrogen releases, determined the causal pathways that led to them, and the frequency of the potential hazardous outcomes. These hazardous scenarios were modeled to estimate their potential harm on station users. The analysis results reveal that the total frequency for a major hydrogen release is 1.48 × 10− 2 times per station-year. However, considering the control barriers in the station, the expected frequency of ignition events is reduced to 1.35 × 10− 5 ignition per stationyear. The expected fatality risk is within the tolerable limit for hydrogen fueling stations, but still remains higher than that of conventional gasoline stations. The most severe scenario identified involves a high-pressure GH2 release leading to a jet fire, with jet flames reaching up to 15 m in length. The most probable sources of GH2 releases are from the gaseous hydrogen filters, while for LH2 releases, cryogenic pumps are the primary contributors. To improve the accuracy of QRAs for LH2 systems, we identified critical gaps, including the need for improved reliability data, that must be addressed.