Greening Ammonia toward the Solar Ammonia Refinery

In light of the targets set out by the Paris Climate Agreement and the global energy sector's ongoing transition from fossil fuels to renewables, the chemical industry is searching for innovative ways of reducing greenhouse gas emissions associated with the production of ammonia. To address this need, research and development is under way around the world to replace the century-old Haber-Bosch process for manufacturing ammonia from N2 and H2, powered by renewable electricity. This involves replacing H2 obtained from steam-reformed CH4 to H2 that is instead obtained from electrolyzed H2O. This transition will enable the changeover from the Haber-Bosch production of NH3 to electrochemical, plasma chemical, thermochemical, and photochemical generation of NH3. If ammonia can eventually be produced directly from N2 and H2O powered by just sunlight, at a technologically significant scale, efficiency, and cost, in a “solar ammonia refinery,” green ammonia can change the world!