Inherent safety assessment of LNG fuelled ships and unkering operations: A consequence-based approach

Liquefied natural gas (LNG) is becoming a viable, environmental-friendly alternative to marine fuel oil for ship propulsion. However, LNG flammability induces relevant safety concerns due to fire and explosion hazards. The present contribution is aimed at the safety assessment of onshore bunkering configurations for marine fuel systems, with particular reference to LNG technologies. A specific review of bunkering methods, including connection to the ship fuel system, is carried out to provide a knowledge background. Moreover, the conventional process configurations based on intermediate fuel oil (IFO) are taken into account for a comparison between process alternatives. A consequence-based approach is followed to develop a set of key performance indicators aimed at evaluating and comparing the inherent safety of LNG and IFO systems. The results obtained allow for a clear identification of critical process units and operations, indicating that conventional IFO bunkering is inherently safer when compared to LNG. Therefore, safety aspects need to be balanced with environmental benefits, in the perspective of sustainable development of LNG supply chain for marine applications.