Renewable ammonia as an alternative fuel for the shipping industry

Decarbonization of the maritime transportation fuels is a primary objective of the shipping industry. Ammonia is an attractive option because of its relatively low greenhouse gas (GHG) emissions, high energy density, competitive cost, and ubiquitous infrastructure for manufacturing, storage, and distribution. The environmental benefits are enhanced when the manufacture of ammonia is assisted by renewable energy and feedstocks. This paper evaluates the potential usage of ammonia, especially renewable ammonia, as a maritime transportation fuel. The assessment covers manufacturing approaches, energy and feedstock sources, economics, and environmental impact based on well-to-tank and tank-to-propeller bases. Comparison is also made with conventional fuels that are currently used in the shipping industry. Finally, the paper discusses future directions and impact of technological advances on the potential use of renewable ammonia as a transportation fuel.