Green ammonia cracking for transport

Decarbonization of energy generation and the transportation sector is crucial to help combat climate change. A convenient way to do this is using hydrogen and/or ammonia, which do not contain carbon. 'Green' ammonia is ammonia produced via the Haber-Bosch process with hydrogen and nitrogen as input feed reactants. Hydrogen is produced from water electrolysis and nitrogen from air separation, both with renewable electricity [1].

Ammonia is dispatchable and has a high energy density and high hydrogen gravimetric content, allowing for easier and cheaper storage and transportation than hydrogen. Ammonia can then be transported and subsequently cracked back to hydrogen where and when it is needed [2]. Moreover, hydrogen is beginning to be widely used in proton exchange membrane fuel cells in transport vehicles or for electricity generation [1].

Thus, ammonia can be used an energy storage vector, allowing for on-demand dispatchable renewable energy and for transport. The impact of which is far reaching in green transport fuels and renewable energy industries, given ammonia's already extensive storage and distribution networks [2] since ammonia is widely used in fertilisers [1].

The aim of the project is to provide a techno-economic analysis of green ammonia cracking for transport. The transport options investigated will be aviation, ships, heavy goods vehicles, passenger vehicles, buses and trains, which all have potential for using hydrogen as a fuel [3].
It is aimed to determine the most efficient and cost effective option from green ammonia cracking. The geographical location of the ammonia input, distance from the cracker to the location of fuelling, distance the vehicle (ship, plane, car etc.) must travel, and centralised/decentralised systems will be investigated on an economic and technical basis, and optimised.

Ammonia cracking requires energy inputs and the conversion of the cracking reaction is not complete, on a large scale (>100 tons per day), it has not been proven commercially or industrially yet [2]. Moreover, ammonia crackers have previously been modelled as steam methane reformers [4] and only very recently in more representative cracking conditions, since ammonia crackers can't yet be straightforwardly modelled in chemical process simulators (such as Aspen PlusTM) [2]. Thus, investigating the technical and economic viability of green ammonia cracking for large scale transport applications will help provide answers to existing research gaps.

This project falls within the EPSRC energy research area, specifically in 'Hydrogen and alternative energy vectors' and 'Energy Storage'.



[1] "Ammonia: zero-carbon fertiliser, fuel and energy store." The Royal Society, London, UK, pp. 1-40, 2020.
[2] C. Makhloufi and N. Kezibri, "Large-scale decomposition of green ammonia for pure hydrogen production," Int. J. Hydrogen Energy, vol. 46, no. 70, pp. 34777-34787, 2021.
[3] "Hydrogen Transport - Fuelling The Future." ARUP, London, UK, pp. 1-12, 2021.
[4] Z. Cesaro, M. Ives, R. Nayak-Luke, M. Mason, and R. Bañares-Alcántara, "Ammonia to power: Forecasting the levelized cost of electricity from green ammonia in large-scale power plants," Appl. Energy, vol. 282, p. 116009, 2021.