Risk assessment of ammonia bunkering operations: Perspectives on different release scales

Ammonia is an alternative marine fuel to reduce greenhouse gas emissions. Conducting studies on ammonia bunkering risk is essential as ammonia is toxic and corrosive to humans and the environment. This study aims to assess the ammonia bunkering operational risk from the perspectives of small, medium and large release scales. Scaling releases from small to medium results in more changes in cloud footprints at lower gas concentrations. Conversely, transitioning from medium to large releases causes more changes in cloud footprints at higher gas concentrations and lethality footprints with higher values. Moreover, this study performs a sensitivity analysis on ammonia bunkering supply, release, and meteorological factors. Wind speed is the most significant factor in small and medium releases, while hose diameter is the most significant factor in large releases. Under the given inputs, a 50% change in wind speed can have up to 100% change in the 1100 ppm maximum cloud footprint for small releases and a 663% change for medium releases. Similarly, a 50% change in hose diameter can result in a 1689% change in the 1100 ppm maximum cloud footprint for large releases. The research provides valuable insights into analysing ammonia bunkering operational risk considering different risk assessment criteria.