Green ammonia as hydrogen carrier: current status, barriers, and strategies to achieve sustainable development goals

Abstract

Hydrogen, a carbon-free fuel, has the potential to aid global nations in achieving eight of the 17 Sustainable Development Goals (SDG). The shortcomings associated with H₂ transportation and storage can be mitigated by using NH₃ as hydrogen carrier because of its better safety, physical, and environmental properties. However, to achieve the global climate target, green ammonia production must be incremented by four times (688 MT) from the current level. Hence, understanding of advanced green NH₃ production and storage technologies, along with the factors that influence them becomes necessary. It also aids in identifying the factors hindering green H₂ and NH₃ production, which can be resolved by promoting research. At the same time, drafting policies that encourage green H₂ and NH₃ production can abet in overcoming the bottleneck faced by the industry. Presently, green ammonia production can be made feasible only when the renewable electricity cost is less than $20/MWh and carbon price of $150/t of CO₂ emissions is levied. Approximately 80 % of the energy consumed during NH₃ is spent on H₂ generation; therefore, it is necessary to enact policies that promote green H₂ production globally. Producing green H₂ can aid in mitigating ∼90 % of the greenhouse gases emitted during NH₃ manufacturing thereby facilitating to reduce the carbon footprint of H₂ carrier and decarbonize NH₃ industry.