Analyzing Interaction Hazards of Battery-Electric Ferries and Hydrogen Fuel Cell Vehicles Using STPA

The transportation sector, like many industries, is working to meet the United Nations (UN) net-zero target by 2050. One promising solution is using alternative energy sources, such as hydrogen, batteries, ammonia, and methanol. These solutions introduce hazards distinct from traditional fossil fuels that become increasingly complex when diverse transport modes utilizing unique energy sources operate within shared physical environments. While safety research on individual zero-emission modes is extensive, the interactive risks arising from the convergence of these technologies remain poorly understood. This paper addresses the safety of batteryelectric ferries transporting Hydrogen Fuel Cell Vehicles (HFCVs). This research employs System-Theoretic Process Analysis (STPA) to analyze a high-risk Simultaneous Operations (SIMOPs) scenario involving the concurrent loading of an HFCV and shore-side high-voltage charging. The analysis reveals complex interactions involving the ferry's Integrated Bridge System, the shore-side charging controller, and the deck crew. Identified loss scenarios include an HFCV hydrogen leak caused by a vehicle collision during loading. Other scenarios trigger cascading failures, such as when electric arcing from a shoreside charger ignites hydrogen being vented from an HFCV, leading to a catastrophic hazard event. Based on these findings, this study proposes safety guidelines to mitigate these loss scenarios.

Keywords: STPA, Simultaneous Operations, Battery-Electric Ferry, Hydrogen Fuel Cell Vehicle, Risk Analysis, System Safety.