Investigating Two Cases of Natech Accidents at Hydrogen Fuelling Stations in Japan

Hydrogen has received a lot of attention recently as a promising energy carrier due to its potential to be produced through renewable sources, offering an entirely clean fuel alternative. An important prerequisite for the effective commercial deployment of sustainable, hydrogen-based solutions for everyday transportation, such as fuel cell electric vehicles, is to develop and make broadly accessible the fundamental infrastructure that will enable their use: hydrogen fuelling stations. Nonetheless, historically one of the key obstacles to the widespread adoption of emergent hydrogen technologies is ensuring their safety and reliability. Apart from the complex technical processes involved in its production and distribution, hydrogen’s chemical characteristics (e.g., high flammability) also pose significant challenges to facility operators and risk managing authorities with regards to cost-effective safety design, reliable operation and efficient resource management of hydrogen fuelling stations. Hydrogen is a hazardous substance, and so any technological accidents caused by natural hazards involving its release can be categorised as Natech events. Considering that fuelling stations typically need to be installed in urban areas and near major traffic nodes in order to offer an easily accessible service to the public, potential accidents can have severe consequences for nearby residents and passers-by. Therefore, identifying critical factors and safety requirements for hydrogen fuelling stations is a crucial step towards minimising these risks. Lessons from past accidents, near-miss incidents, response practices and effective prevention and mitigation measures are essential in this regard. In this context, we focus on potential Natech accidents at hydrogen fuelling stations and venture to extract lessons from past incidents. In detail, this study analyses the records concerning hydrogen fuelling stations of the accident report database of the High-Pressure Gas Safety Institute of Japan from 2005 to 2022. Focusing on incidents involving hydrogen releases caused by natural hazards, we present two cases: one in Tokyo (2011) and another one in Aichi prefecture (2021). Through examining these past accident reports, we identify risk factors for potential Natech accidents at hydrogen fuelling stations. Finally, we discuss safety barriers from an organisational and technical perspective in hopes of providing recommendations and lessons for hydrogen fuelling station operators and risk management authorities. The contribution of this work lies in expanding our current understanding on the uncertainties, atypical losses, and associated risk reduction measures concerning hydrogen fuelling stations in the context of Natech.