Scientists from the University of Manchester have published research that explores the potential of green ammonia as an alternative fuel option for the shipping industry.
The paper “Green ammonia adoption in shipping: Opportunities and challenges across the fuel supply chain” highlights that green ammonia benefits from the existing experience of storing and transporting ammonia in the global fertilizer sector, along with recent moves toward incorporating dual-fuel engines in the shipping fleet.
However, the findings reveal a wide range of challenges that undermine its viability and adoption as a genuinely green alternative, particularly within the timelines established by the Paris Agreement to limit global warming to 1.5°C by 2050.
Challenges in transitioning to low-carbon fuels
To effectively align with the Paris Agreement, the international shipping sector must overcome challenges associated with being first movers in transitioning to low-carbon fuels. The industry is currently in an exploratory phase that, while potentially fostering technological innovation, also presents obstacles due to increasingly shorter timelines for compliance.
The anticipated escalation of compliance costs and the lack of relevant supply-side infrastructure further complicate the situation. Additionally, there remains uncertainty about the release of nitrous oxide (N2O)—a potent greenhouse gas—from ammonia combustion in real-world conditions, raising questions about its environmental credentials.
Moreover, ammonia’s significant toxicity necessitates the implementation of new safety regulations to protect mariners and the marine environment. The absence of clear policy drivers and the competing demand for green ammonia and hydrogen from other sectors contribute to perceived economic risks, which impede its adoption.
This situation delays the necessary development of supply chain infrastructure, particularly concerning port storage, handling, and transportation, and creates hesitation in investing in ships designed for alternative fuels.
Need for a broader focus on emission reduction strategies
Although some vessels are being built or retrofitted with dual-fuel engines to be “alternative fuel ready,” there is currently no significant shift towards using lower-carbon alternatives at a meaningful scale. If this trend continues, it could delay the transition and increase the shipping sector’s climate contribution instead of mitigating it. The paper argues that effective policymaking must simultaneously address all elements of the supply chain to overcome these highlighted barriers.
Furthermore, many challenges faced in adopting green ammonia are likely to be encountered when considering other alternative fuels, particularly those that are more energy and resource-intensive to produce, which would in turn lead to higher production, storage, and transportation costs.
This dynamic suggests a pressing need for the shipping industry to implement additional emission mitigation measures in parallel, such as slow steaming, wind propulsion, route optimization, and the myriad ship efficiency improvements already available.
These strategies could reduce fuel consumption and help mitigate financial risks. Importantly, unlike the available fuel options today, these measures have a greater potential to deliver near-term emission reductions in alignment with the International Maritime Organization’s (IMO) 2030 and 2040 targets.
