The Environmental Feasibility of Decentralised Solar Ammonia

Abstract

Intense efforts have been devoted to developing green and blue centralised Haber-Bosch processes (gHB and bHB, respectively), but the feasibility of a decentralised and sustainable scheme has yet to be assessed. Here we reveal the conditions under which small-scale systems based on the electrocatalytic reduction of nitrogen (eN₂R) powered by photovoltaic energy (NH₃-leaf) could become a competitive technology in terms of environmental criteria. To this end, we calculated energy efficiency targets based on solar irradiation atlases to guide research in the incipient eN₂R field. Even under this germinal state, the NH₃-leaf technology would compete favourably in sunny locations relative to the business-as-usual production scenario. The disclosed sustainability potential of NH₃-leaf makes it a strong ally of gHB toward a non-fossil ammonia production.