Decoupling the synthesis of ammonia from the use of fossil fuels is critical to sustainably meet the projected increase in the demand for fertilizers due to the growing population. In contrast to intense efforts devoted to developing a green Haber-Bosch (HB) process, the feasibility of decentralized sustainable ammonia production has yet to be assessed. In fact, a distributed approach could facilitate the establishment of an ammonia economy, where this compound plays the double role of precursor for other chemicals and of energy vector.^[1] Herein we assess the question of where and to what extent solar ammonia may be a valuable strategy. Small‑scale reactors performing electrocatalytic reduction of nitrogen powered by photovoltaic energy (NH₃-leaves) are studied, assuming water as a direct co-reactant. We included scenarios where the water electrolysis reaction yields hydrogen as a by-product, later converted on-site with a fuel cell, to account for the imperfect selectivity of the best state‑of‑the‑art electrolyzers. The environmental and economic impacts of the selected processes were assessed, employing the global warming impact (GWI) and the levelized cost of ammonia. We found that environmental benefits are maximized for GWI. Several technical parameters were varied in the analysis, leading to an atlas of breakeven electricity-to-NH₃ efficiencies required to outperform industrial and green HB (GHB) on the assessed metrics worldwide. Modest values of less than 19% (HB) and 22% (GHB) are sufficient for the average irradiation in the case of GWI, values already comparable to the current state-of-the-art efficiency.^[2] Production costs are estimated between ca. 1.5 and 25.7 USD kg_NH3^-1. These performance requirements can guide the development of NH₃-leaves and suggest that they may become a strong ally of GHB to develop a sustainable ammonia production scheme.