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.