Parameters affecting the reliability of sampling during the assessment of the purity of hydrogen used as a vehicle fuel

It is foreseen that hydrogen heavy-duty (HD) vehicles will be used to a large extent to support the transition to zero emission transport in Europe by 2050. Ensuring the quality of hydrogen is crucial to guarantee a smooth transition. To demonstrate the quality of hydrogen, sampling systems adapted to HD conditions are being developed and tested as part of the EU-funded project MetHyTrucks (Metrology to support standardisation of hydrogen fuel sampling for heavy duty hydrogen transport). Poor sampling can lead to damage to fleets of HD vehicles, making standardization crucial for the shared HD Hydrogen Refuelling Station (HRS) network. Reliable, specific sampling systems for HD-HRS, designed for both gaseous and particulate phases, are currently being developed in the European Partnership on Metrology project MetHyTrucks. The dynamic nature of a HD-HRS, with changes in pressure, flow and temperature during refuelling, can affect the reliability of sampling. Moreover, the hydrogen fuel sampling at the HD-HRS is an operation performed in a potentially explosive atmosphere area involving safety risks. This paper discusses the parameters that can affect sampling when assessing hydrogen purity at a HD-HRS.