Green ammonia adoption in shipping: Opportunities and challenges across the fuel supply chain

The IMO’s 2023 revised targets increase pressure on shipping and trading organisations to urgently cut energy consumption and transition away from fossil fuels. Although there are several alternative fuel options for shipping, ammonia is a prominent contender. Green ammonia is produced from renewable hydrogen with no direct CO₂ emissions when combusted, making it an important option to interrogate. This research uses a mixed methods approach, including analysing shipping stakeholders’ perspectives, to consider the full range of factors relating to its deployment and use. Challenges to its adoption include low fleet renewal as a result of uncertainties around being first movers, managing NO_x and N₂O emissions if used in a combustion engine and lack of economic incentives. Nevertheless, green ammonia’s storage advantages over hydrogen, established experience of ammonia handling for the fertiliser industry and its direct emission free application in fuel cells, underpin interest in its development. The study emphasizes though that the on-ground realities of transitioning away from fossil fuels require significant developments across the entire fuel supply chain. This extends beyond considerations around ammonia’s technological viability and encompass changes needed to onboard and portside infrastructure, incentives to accelerate retrofit and fleet renewal, and recognition of risks posed by first-movers in the sector. Furthermore, with short timeliness associated with Paris targets, and anticipated rising costs of new fuel infrastructure, there is an imperative to implement mitigation policy that focuses on urgently reducing reliance on liquid fuels, while alternative fuel deployment is established at scale.