Progress last year toward the development of ammonia as a maritime fuel of the future was significant. There was a notable increase in orders for ammonia-fueled vessels in 2024, compared with 2023. Moreover, several engine manufacturers, including MAN Energy, Win GD, and Wärtsilä, made progress announcements.

In December, the International Maritime Organization (IMO) approved interim guidelines at a meeting of its Maritime Safety Committee (MSC) which, for the first time, set international safety procedures for the use of ammonia as a marine fuel. Ammonia is not currently covered by the International Code of Safety for Ships Using Gases or Other Low-flashpoint Fuels (IGF Code), so the latest IMO guidance is a significant step forward.

The IMO interim guidance advised several areas including restricting hazardous and toxic spaces, minimising ammonia releases, advising mitigation systems, ensuring sufficient ventilation of fuel tanks and the provisions of safe havens on board.

However, the guidelines are non-mandatory and will likely see several revisions over the coming years. The IMO will review them again in either 2026 or 2027.

Of interest, ammonia cargo can be used as a fuel on gas carriers as of 1 July 2026, following the MSC’s agreed amendment to existing policy.

The impact of legislation

Renewable and alternative fuels such as low-carbon ammonia received a boost from legislation in 2024 and will continue to do so in 2025. The EU Emissions Trading System (ETS) was extended in 2024 to cover maritime, meaning that emissions on voyages and port calls within the European Union/European Economic Area must now be covered by the required EU Allowances (EUAs). The phase-in period runs to the end of 2025, with 100% of 2026 emissions (carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4)) to be covered by allowances in 2027.

From January 2025, FuelEU Maritime comes into force, setting requirements for the annual average greenhouse gas intensity of energy used by ships within the EU/EEA, based on a well-to-wake accounting system. It starts with a 2% reduction target in 2025 (versus a 2020 baseline), increasing to an 80% reduction by 2050.

Both pieces of legislation, which are independent of each other, add a cost burden to conventional, CO2-emitting fuels. FuelEU Maritime will give alternative, low-carbon fuels a greater value by also factoring in the production process. However, ETS Maritime will likely be more impactful than FuelEU through the 2020s because of the latter’s gradual phasing-in process.

Some old challenges remain

Despite the clear progress being made, some old challenges remain. Safety concerns persist because ammonia is toxic. This has led to pushback from the public as well as parts of the maritime sector, creating additional crewing considerations.

Its lower energy density compared with traditional marine fuels prompts questions about efficiency, while the expected higher cost of low-carbon ammonia versus conventional fuels on a comparative basis, remains a lingering concern. Although sulfur and carbon free at point of combustion, ammonia does emit nitrogen oxides (NOx) and N2O, the latter of which is measured under both the ETS maritime extension, as of 2026, and FuelEU regulations. However, there is established technology available to mitigate these emissions.

Looking ahead to 2025 and beyond

Orders for ammonia-fueled vessels will continue to rise in 2025. However, there is still uncertainty about what will be the leading fuel or fuels of the future. No one fuel is projected to dominate, not least because regulations are expected to continue to change.

As a result, dual-fuel technology demand has grown as buyers opt for functionality and flexibility. Liquefied natural gas (LNG) dual fuel was the most prominent choice in 2024, said attendees at a recent shipping industry gathering.

Ammonia’s potential as a marine fuel is backed by Chemical Market Analytics by OPIS’s detailed market analysis and forecasting, in the new Global Ammonia Service launching in January 2025. 

Author 
Carl Roache, Executive Director, Ammonia and Urea
Chemical Market Analytics by OPIS

Carl Roache is the Executive Director of Ammonia and Urea at Chemical Market Analytics. He joined the company in 2024 and leads analysis and pricing globally from London, UK. Before joining CMA, Mr. Roache was EuroChem’s global business development manager for NPK fertilizers, based in Dubai, UAE. From here, he coordinated global NP/NPK sales from the company’s 1.2mn t/yr Antwerp plant. Before this, he was EuroChem’s Asia NPK business development lead, based in Singapore. Mr Roache has also worked for price reporting agencies within the fertilizer sector in the UK and Asia, including spells as global nitrogen and potash lead (ICIS) and Europe and Asia regional editorships (Argus Media).