Ammonia as a marine fuel: likelihood of ammonia releases

Abstract

The maritime industry is transitioning to low or zero carbon fuels and ammonia is one of the potential substitutes for conventional fuels. For safe use of ammonia as a fuel, risk assessment is necessary to address the hazards presented by ammonia and to provide insights where experience as a fuel does not exist. Therefore, it is important to estimate the likelihood of ammonia releases is important. However, there is a lack of applicable leak data within the maritime industry. This study examines applicability of leak data from oil and gas industry by comparing the historical ammonia leak frequency recorded in the LPG tankers carrying ammonia with leak frequency estimate derived from the oil and gas data. The analysis shows that the oil and gas data provide a more conservative estimate than the historical leak frequency, concluding that the oil and gas data can be considered as a useful starting point for estimating the likelihood of ammonia releases. In addition, the ammonia leakage frequency of an ammonia-fuelled LPG carrier is estimated using the oil and gas leak database. The estimated frequency is approximately 0.054 per year, suggesting that the vessel could experience more than one ammonia leaks during operation.