Techno-Economic Optimization of a Decentralized, Small-Scale Electrochemical Haber-Bosch Process for Green Ammonia Production

Ammonia has become a strategic compound for sustainable energy systems due to its carbon-free structure, high hydrogen density and compatibility with existing infrastructures. In this study, the technical and economic feasibility of green ammonia production based on the electrochemical Haber-Bosch (eHB) process is analysed in detail. Modelling results show that reactor pressure and electrolyser efficiency have decisive effects on the levelized cost of ammonia (LCOA) and operating expenses (OPEX). Under pressures above 9 MPa, the conversion efficiency and the residence time in the reactor decreases, decreasing the conversion efficiency but resulting in a smaller reactor volume, thus reducing reactor costs. Especially at electricity prices as low as 30 USD/MWh, LCOA has been observed to be competitive with conventional methods at scales above 25 tonnes/day. Furthermore, increases in capacity factor and production scale improve economic performance by spreading capital and fixed operating costs over a larger production volume The results demonstrate that high-pressure eHB systems supported by renewable sources offer an industrially viable and competitive option for decentralised green ammonia production across various sectors, from the fertiliser industry to hydrogen carrier applications.