Quantification ofHydrogen Emission Rates Using DownwindPlume Characterization Techniques

Fugitive and operational hydrogen (H₂) emissions have been shown to offset the intended climate benefits of H₂ as a decarbonization tool because H₂ indirectly causes warming through atmospheric chemistry. However, little is known about the magnitude of value-chain H₂ emissions due to a lack of empirical measurements, the unavailability of precise, fast sensor technology, and the lack of established methods for emission quantification. In this study, a novel prototype H₂ sensor was deployed in a state-of-the-art mobile laboratory to demonstrate that H₂ emissions can be accurately quantified using downwind measurement techniques and analytics commonly used for other gases. A series of controlled H₂ release experiments were conducted with the corelease of multiple tracer gases. Tracer flux ratio and physics-based Bayesian plume model inversion methodologies were used to quantify the H₂ emission rates. We show that the H₂ sensor detects parts-per-billion or higher concentration enhancements downwind of the H₂ emission source within seconds, and the similar plume structures of H₂ and tracer gases confirm their codispersion in the atmosphere. This enables the quantification of H₂ emission rates at an accuracy comparable to that of other well-studied gases.