Green ammonia production: Process technologies and challenges

Ammonia, a vital player in the global economy, propels economic growth through its key role in fertilizer production, boosting agricultural output significantly. While traditional methods dominate its production, recent efforts focus on sustainable pathways like green ammonia, produced using renewable energy. This colourless gas, beyond agriculture, becomes a versatile input in chemical manufacturing, finding applications in solvents and fertilizers. Industries are increasingly adopting green pathways to reduce carbon footprints, exploring methods using green hydrogen and CO2 by-products. Green ammonia, a beacon for decarbonization, surpasses hydrogen in volumetric energy density, making it a preferred energy carrier. Power-to-Ammonia technology supports energy storage and transfer capabilities, aiding renewable energy integration. Despite challenges like low reactivity, NOx emissions, and toxicity, ammonia's global demand is projected to rise to 350 million tonnes/year by 2050. This review article emphasizing the need for sustainable ammonia production to achieve economic competitiveness, environmental sustainability, and a carbon-neutral future.