From LNG to LH2 in Maritime Transport: A Review of Technology, Materials, and Safety Challenges

The adoption of low-carbon fuels in maritime propulsion requires operational autonomy, material suitability, and compliance with safety standards, making liquid fuels like LNG and LH2 the most viable options. LNG is widely used for reducing GHG, NOx, and SOx emissions, while LH2, though new to the maritime sector, leverages aerospace experience. This paper explores the operational requirements and challenges of LH2 cryogenic handling systems using LNG practices as a reference. Key comparisons are made between LNG and LH2 supply systems, focusing on cryogenic materials, hydrogen embrittlement, and structural integrity under maritime conditions. Most maritime-approved materials are suitable for cryogenic use, and hydrogen embrittlement is less critical at cryogenic temperatures due to reduced atomic mobility. Risk assessments suggest LH2’s safety record stems from limited operational data rather than superior inherent safety. The paper also addresses crucial safety and regulatory considerations for both fuels, underscoring the need for strict adherence to standards to ensure the safe and compliant integration of LH2 in the maritime industry.