Safe Hydrogen Fuel Handling and Use for Efficient Implementation - SH2IFT

There is an increased interest in hydrogen as a clean energy carrier that can contribute to realize the needed global reductions in greenhouse gas emissions. In particular, decarbonization of sectors such as power and industry, as well as several modes of heavy-duty transportation are of high interest. However, insufficient knowledge about safety issues related to widespread roll-out of hydrogen technology represents a major bottleneck for industry, authorities, end-users as well as the general public. To avoid unnecessary restrictions regarding handling and use of hydrogen, knowledge gaps related to safety must be filled, thereby mitigating potential hazards and lowering barriers to widespread implementation. Hence, validating consequence models against experiments and establishing and disseminating knowledge and guidelines regarding hydrogen safety is of key importance for the future hydrogen society. The SH2IFT project combines social and technical scientific methods to address knowledge gaps regarding safe handling and use of gaseous and liquid H2, and theoretical approaches are complemented by fire and explosion experiments, with emphasis on topics of strategic importance to Norway, such as tunnel safety and maritime applications. The research partners in the project are NTNU, NORCE/Gexcon, RISE Fire Research, SINTEF and TØI. The general population survey which was performed indicates that overall knowledge of hydrogen as fuel is low, that it is considered sustainable, and that perceived safety is an issue. The perceived safety concerns for hydrogen fuel use are significantly correlated with the awareness of the 2019 hydrogen station explosion in Norway. Active campaigns to boost familiarity with hydrogen fuel can help to increase the perceived safety. The impact of jet-fire flames on enclosure structures were evaluated by assessing the thermal exposure of the inside of the enclosure. Both visible and (for human observers) invisible flames were recorded. It was found that the visibility of the flame was highly dependent on the ambient conditions. As most of the heat from the jet flame is transferred through convection, the heat flux to the impinged surfaces is concentrated around the impact point of the jet, where for a very short duration, a peak incident heat flux of 700 kW/m2 was measured. The thermal heat flux to the surroundings caused by a hydrogen jet fire is therefore more directional compared to hydrocarbon jet fires. Large-scale liquid hydrogen (LH2) experiments have been performed to study the behaviour of storage tanks when exposed to a fire. For this purpose, 3 double-walled vacuum insulated tanks of 1 m3 were built with different insulation materials and tank orientations (horizontal and veritical). One out of the three tanks failed catastrophically after 1 hour and 6 minutes, whereas the other two tanks managed to stay intact after having been exposed to a fire for 1 hour and 20 minutes and 4 hours respectively. The tank that failed resulted in a large fireball, fragments and a blast wave. Safety valves were closed during all tests. In addition, large-scale experiments were performed to study the behaviour of liquified hydrogen when released onto water or under water. In total 60 experiments were performed, where liquified hydrogen were released at different rates into a basin. All release configurations above and under water resulted in a very chaotic LH2-water mixing zone, causing considerable evaporation resulting in minor overpressures. No Rapid Phase Transitions (RPTs) were observed. In most of the tests, the gas cloud resulting from the evaporation was ignited by a yet unknown source. The cause of ignition needs to be addressed by further research. In parallel, a theoretical assessment of triggering and hypothetical consequences of RPT for liquified hydrogen has been completed. The overall conclusions are that triggering of an LH2 RPT event as a consequence of a spill on water is very unlikely and that the hypothetical consequences of LH2 RPT are small compared to LNG RPT. This matches well with the experimental results. Boiling liquid expanding vapour explosion (BLEVE) models were validated against LH2 tests performed by BMW during the 1990’s. An analysis of these experiments using a CFD-simulation tool showed that both the gaseous and liquid phase inside tanks containing LH2 contribute to blast pressures generated by BLEVEs of such tanks. On this basis suggestions were made to improve existing analytical models. Moreover, it was speculated that a small fraction of the combustion process contributes to the blast wave overpressure, as already demonstrated for high-pressure gaseous hydrogen tanks. Finally, the fire test was simulated to investigate the behavior of the tank lading prior its rupture by means of both analytical and numerical models, with the aim of assessing the time to failure of the tank. More details are found in the final report: www.sh2ift.com

During this KSP project, the partners have developed working methods and digital tools for studying liquid and gaseous hydrogen. The partners have made progress in the understanding of important parameters related to hydrogen safety.There is a significant effort in developing infrastructure for the green energy shift. It is critical that safety is considered as a part of the totality, and sufficient knowledge, recommendations and procedures will help new hydrogen applications find its way on the market. This is a significant business opportunity for value creation from Norwegian natural resources. SH2IFT may also promote new technology within detection, ventilation and fire extinguishing techniques. SH2IFT focused on challenges especially relevant for the Norwegian industry, and were identified through close collaboration between the industry- and research partners. The knowledge obtained increases the probability of long term value creation within industry segments important for Norway, such as power/gas as well as maritime and transportation industry. The SH2IFT project has also educated highly competent scientists for future developments and for the progress of existing production as well as future expansions. SH2IFT is an interdisciplinary project, and we have been a number of research and industry partners who have been involved and have collaborated across different work packages. This has provided useful insight into each other's research fields. Several international partners have also been involved. This has resulted in an expanded network and plans to continue the good collaboration in a follow-up project, SH2IFT-2. SH2IFT has contributed to increase knowledge, guidelines and procedures that will address new and upcoming technology from a Norwegian perspective. The project initiated new collaboration between research, industry, authorities and other relevant actors within hydrogen safety, and has established a platform of common understanding of hydrogen related safety issues. SH2IFT concluded with a high-impact hybrid event in Trondheim in May 2022, with attendees from research, industry, authorities and policymaking bodies. The event was streamed and can be viewed at the project website www.sh2ift.com

The Norwegian energy policy presents a political initiative to introduce H2 as fuel. This opens for the use of H2 in several modes of transportation, as well as to support the build-up of intermittent, renewable energy storage. Norway has extensive experience from H2 producing by electrolysis and methane reforming, and can become a supplier of clean hydrogen and H2 technology to Europe and other parts of the world. Large industrial actors are currently exploring the potential of producing large quantities of sustainable H2 from Norwegian natural gas with solutions that include carbon capture and storage. However, insufficient knowledge about safety issues related to widespread roll-out of H2 technology represents a major bottleneck for industry, authorities, end-users and the general public. To avoid unnecessary restrictions regarding handling and use of H2, knowledge gaps related to safety must be filled, thereby mitigating potential hazards and lowering barriers to widespread implementation. Hence, validating consequence models against experiments and establishing and disseminating knowledge and guidelines regarding H2 safety, especially for use in the general public, is of key importance for the future H2 society. The proposed project, SH2IFT, combines social and technical scientific methods to address knowledge gaps regarding safe handling and use of gaseous and liquid H2, and theoretical approaches will be complemented by fire and explosion experiments, with emphasis on topics of strategic importance to Norway, such as tunnel safety, maritime applications, etc. Impact -Increased relevance and accuracy of consequence models and risk assessments, resulting from experimental investigations and state-of-the-art modelling; -Input to requirements, procedures and guidelines regarding GH2 and LH2 safety in road, rail and maritime applications; -Increased acceptance and accelerated implementation of H2 technology in society, contributing to reduced GHG emissions