Cost, techno-economic feasibility and environmental impact mitigation potential of green ammonia fertilizer manufacturing and use in agriculture: A systematic review

Inorganic nitrogen (N) fertilizer is an important input in the agri-food sector to maximise crop yield and land productivity. Ammonia, the basic feedstock for inorganic N fertilizer production, is currently synthesized from the steam methane reforming of natural gas. This conventional process is both energy and carbon intensive, contributing 1–2% of global anthropogenic carbon dioxide emissions and a significant share of agricultural greenhouse gas emissions. To meet net-zero emissions climate targets in the agri-food sector, there is a need to transition to alternative low-carbon ammonia production methods. Hence, the goal of this systematic PRISMA review was to investigate and evaluate the cost, techno-economic feasibility and environmental impact mitigation potential of inorganic N fertilizer production that uses renewable energy in place of natural gas to produce “green” ammonia via the well-established Haber-Bosch process. The review highlights that green ammonia production could reduce life cycle greenhouse gas emissions in the fertilizer industry by up to 98% compared to conventional production. However, widespread adoption remains constrained by technical and economic barriers. Under current average renewable electricity prices, the median levelized cost of green ammonia production is ∼2–7 times greater than conventional. Beyond climate change mitigation potential, the review identifies environmental trade-offs between energy, land, water and material use that must be carefully managed to facilitate a sustainable transition. Finally, the feasibility of green ammonia production at the farm scale is assessed as a complementary approach to large-scale production, with potential to enhance the resiliency and robustness of the agriculture industry.