System-Level Knowledge Gaps in Liquid Hydrogen Storage Integration for Maritime Applications

Liquid hydrogen (LH 2 ) is considered an environmentally sustainable fuel for maritime decarbonization because it does not directly emit greenhouse gases (GHGs). However, integrating LH 2 onboard ships poses yet unresolved technical, operational, and regulatory challenges. Considering this, the status of research on LH 2 tank integration in maritime applications is systematically reviewed in this study, with an emphasis on identifying and structuring existing knowledge gaps. It is observed that, despite significant advancements in individual domains, there is a considerable underrepresentation of system-level research on integrating LH 2 storage systems onboard ships and the associated operating conditions. Furthermore, the analysis conducted in this study reveals a substantial gap between current research and the requirements for large-scale implementation. Hence, this paper proposes a research roadmap based on these findings. It outlines key focus areas for further research, including, but not limited to, integrated system modeling, pilot-scale demonstration, and development of standardized design and safety protocols.