Quantifying H2 emissions of new and existing infrastructure

The hydrogen value chain, including the production, distribution, storage and end use of H₂, is growing around the world. Although hydrogen is viewed as a sustainable energy carrier, it has an indirect radiative effect. H₂ is a leak prone gas, and emissions from leaks/purging/venting across the H₂ value chain could lead to increased H₂ mole fraction in the atmosphere. Through the reaction of H₂ with OH, this would increase mole fractions of CH₄, tropospheric ozone and stratospheric water vapour, all of which result in warming. Hence, the GWP20 and GWP100 of H₂ are estimated to be around 37 and 12, respectively.

Therefore, measurements of emissions of H₂ from existing and new hydrogen infrastructure are needed. However, low levels of H₂ are difficult to measure and suitable measurement technologies are becoming available only recently. One such technology is the Aerodyne Research TILDAS H₂ monitor. This monitor has a high precision (down to 5 parts per billion which is 100 times below ambient), has fast time resolution (5 seconds), and can perform continuous 1 Hz air measurements. The instrument has been found to successfully observe a wide range of mole fraction enhancements of H₂ on a mobile platform, and these plumes can be converted to emission rates with dispersion models and/or release of tracers at controlled rate. Emission rates from new and existing infrastructure such as refuelling and refilling stations, pipelines, electrolysers and buses will be presented here.