Techno-Economic Analysis of Active and Passive Liquid Hydrogen Storage Systems.

Abstract

Green hydrogen is increasingly recognized as an important part of the renewable energy transition. It provides a clean and flexible energy source that can help replace fossil fuels in sectors that are hard to decarbonize. Effective storage is crucial for energy security and economic feasibility, especially in local wind-to-hydrogen hubs. Liquid hydrogen (LH₂) is a promising option due to its high volumetric density, but its very low boiling point of -253 °C creates challenges such as boil-off and high energy use. Comparing different LH₂ storage methods is necessary to guide the development of future hydrogen hubs.

This study looked at the technical and economic trade-offs between active and passive LH₂ storage systems. For 30 days, data from engineering standards and published studies were used to estimate boil-off rates, cryocooler performance, and costs. In a 5,000 kg tank, the passive system with advanced multilayer insulation lost 15 kg of hydrogen (0.01%), while the active system used about 384 kWh of electricity but prevented boil-off. These results show the balance between hydrogen loss in passive storage and energy use in active storage.

A sensitivity analysis was done to see how scaling and market conditions affect the results. When the storage size increased to 195,000 kg, the passive system lost about 585 kg of hydrogen in 30 days, and the active system's energy use went up to over 15,000 kWh. The cost comparison changed with different price assumptions: passive storage was cheaper at current hydrogen prices (£4.6/kg) but less attractive as prices neared £10/kg. Active storage became more competitive when electricity prices dropped to £0.05–0.10/kWh, which is possible in areas with lots of renewable energy. These findings suggest that neither system is always better; the best choice depends on scale, prices, and how the storage will be used.

Future research should include not just operating costs but also capital costs, maintenance, and factors like cryocooler servicing and insulation wear. It is also important to model how storage works across different seasons. Covering these areas will help techno-economic studies give a fuller view of hydrogen storage and support the creation of reliable and affordable local hydrogen hubs.