Techno-economic prospects of ammonia as a carbon-free alternative to liquefied natural gas

The high energy density of hydrocarbon fuels makes them highly practical for use in transportation and international energy trade. As the global decarbonization effort gathers momentum, hydrogen is often portrayed as the successor of hydrocarbon fuels. However, hydrogen is much harder to transport and store, losing the key benefits that the fuels it is meant to displace offer. Ammonia is a promising alternative to hydrogen, preserving the most important benefits of today's fuels, largely because it can be liquefied relatively easily. The present work looked specifically at the potential of ammonia to compete with liquified natural gas (LNG) as a vector for global energy trade. Dedicated bottom-up techno-economic assessments and benchmarking showed that large-scale deployment of advanced ammonia production based on membrane-assisted autothermal reforming can compete with LNG at moderate CO₂ prices around 96 $/tonne. If the captured CO₂ can be used productively for enhanced oil/gas recovery from nearby wells, the breakeven CO₂ price can drop below 70 $/tonne. However, commercially available ammonia production processes built at smaller scales will require CO₂ prices well over 200 $/tonne to compete. Thus, policy incentives will be required to create demand among suitable early adopters (e.g., international shipping), incentivising investment in development and large-scale deployment of ammonia production as an alternative to natural gas liquefaction.