Hydrogen sampling systems adapted to heavy-duty refuelling stations' ' current and future specifications - A review

To meet the new regulation for the deployment of alternative fuels infrastructure which sets targets for electric recharging and hydrogen refuelling infrastructure by 2025 or 2030, a large infrastructure comprising truck- suitable hydrogen refuelling stations will soon be required. However, further standardisation is required to support the uptake of hydrogen for heavy-duty transport for Europe's green energy future. Hydrogen-powered vehicles require pure hydrogen as some contaminants can reduce the performance of the fuel cell even at very low levels. Even if previous projects have paved the way for the development of the European quality infrastructure for hydrogen conformity assessment, sampling systems and methods have yet to be developed for heavy-duty hydrogen refuelling stations (HD-HRS). This study reviews different aspects of the sampling of hydrogen at heavy-duty hydrogen refuelling stations for purity assessment, with a focus on the current and future specifications and operations at HD-HRS. This study describes the state-of-the art of sampling systems currently under development for use at HD-HRS and highlights a number of aspects which must be taken into consideration to ensure safe and accurate sampling: risk assessment for the whole sampling exercise, selection of cylinders, methods to prepare cylinders before the sampling, filling pressure, and venting of the sampling systems.