LH2CRAFT intends to contribute to the development of a H2-based economy, and towards this direction the key enabling technology and the fundamental problem that needs to be addressed is its storage and transportation. The most efficient way of transportation of H2 is in liquid form and the greatest challenge when transporting LH2 (via ships) is the efficient handling and storage, especially of large quantities. Storing LH2 involves a variety of challenges and problems that LH2CRAFT aims to address:
• Very low storage temperatures of LH2 (-253°C), requiring a highly sophisticated design of tank systems with excellent thermal insulation and avoiding formation of thermal bridges in the structural parts of the tanks.
• The materials used in the structure of the tanks should safeguard the long-term structural integrity of the structure, during continuous contact in the cryogenic environment.
• Relatively low volumetric density of LH2 requires large storage systems. Heat leakage is less severe for larger LH2 tanks because the amount of stored H2 scales with the volume of the tank while heat leakage through the outer surface scales with the surface area of the tank (i.e., as the square of the tank’s spherical radius).
• During, storage and transportation of LH2 via both terrestrial and marine transportation, a boil-off of about 0.2% to 0.3% may occur because of several factors, including heat leakage, ortho-para conversion, sloshing, and flashing (critical for long time storage.) For example, during a H2 powered airplane relevant research project of University of Stuttgart it was estimated that during a flight mission of 3 hours, 50.4 kg of LH2 evaporate due to boil off.
• Loss rates along the H2 supply chain are not well constrained and are currently estimated to span from a small fraction for compressed H2 (1-4%) to up to 10-20% for liquefied H2. In this context, the main challenge to reduce the LH2-related losses on the overall supply chain is addressed on T5.2, T6.3 and T6.4, where the distribution subsystems (including bunkering and startup) are designed, tested and validated on materials and components level. The estimated rate of losses will be then fed to WP8 and WP10 to address the safety and techno-economic impact of the CCS, respectively.
• The structural integration of LH2 tanks in the primary systems of ships increases the risks related to its structural integrity, as already identified and mitigated similarly by the available LNG tank integrated designs.
