Natural isotope fingerprinting of produced hydrogen and its potential applications to the hydrogen economy

Stable isotopes of hydrogen (2H/1H) carry natural fingerprints of produced hydrogen by mode of origin which are difficult or costly to adulterate. A newly compiled database of 5677 measurements reveals that green hydrogen (electrolytic or biological hydrogen, e.g., nitrogenase, hydrogenase) is readily distinguished by its considerable depletion in heavy isotopic species, ranging from −831 to −555 ‰ in δ2H relative to Vienna Standard Mean Ocean Water (V-SMOW), as compared to −377 to +196 ‰ for fossil fuel sources (grey/turquoise hydrogen), and −379 to 0 ‰ for wood/biomass burning (brown hydrogen), compared to analytical uncertainty of close to ±1 ‰. White hydrogen, naturally produced in a variety of geologic settings, ranges from −996 to −49 ‰, reflecting diverse overlapping origins. Potential applications of fingerprinting include tracking of produced hydrogen by source, process and distribution control, grading and regulation of low carbon intensity (CI) products, and leakage detection for carbon storage operations.