Planetary Boundaries Analysis of Low-Carbon Ammonia Production Routes

At present, the synthesis of ammonia through Haber–Bosch (HB) process accounts for 1.2% global carbon emissions, representing roughly one-fourth fossil consumption from chemical industry, which creates a pressing need alternative low-carbon routes. Analyzing seven essential planetary boundaries (PBs) safe operation our planet, we find that standard HB is unsustainable as it vastly transgresses climate change PB. In order to identify more responsible strategies this integrated perspective, assess absolute sustainability level 34 routes where hydrogen (H2) supplied by steam methane reforming with capture and storage, biomass gasification, or water electrolysis powered various energy sources. We found some these scenarios could substantially reduce impact HB, yet alleviating on critically exacerbate impacts other Earth-system processes. Furthermore, reducing cost electrolytic H2 main avenue toward economic appeal most sustainable Our work highlights embrace beyond in assessment decarbonization chemicals. This approach enabled us suitable alternatives associated challenges environmental economically attractive synthesis.