Ammonia-fuelled ships moved from demonstrators to commercial service in 2026 when Exmar's 46,000 m3 LPG/ammonia carrier Antwerpen was delivered with a WinGD X52DF-A engine. Two-stroke tests show N2O below 3-5 ppm at about 5% pilot fuel, but the orderbook is tiny, the IMO safety framework is interim and green ammonia costs USD 600-1,000/t.
What it is and how it works
Ammonia carries no carbon, so burning it emits no CO2 at the funnel, but it is toxic, hard to ignite and can form nitrous oxide (N2O), a potent greenhouse gas. Marine ammonia engines are therefore dual-fuel designs that inject ammonia alongside a pilot of diesel or fuel oil. WinGD reported full-load X-DF-A tests with N2O below 3 ppm and ammonia slip below 10 ppm without exhaust aftertreatment, with pilot fuel at 5% of consumption and thermal efficiency matching diesel; Everllence describes N2O from its ME-LGIA test engines as typically well below 5 ppm, per the Ammonia Energy Association. J-ENG's 7UEC50LSJA completed official tests in August 2025 with N2O of about 3 ppm and more than 90% GHG reduction at 95% ammonia energy share. These are maker-reported results.
Four-strokes behave differently: IHI engines show untreated N2O of about 20 ppm, nearly fully removable by catalyst, and Wärtsilä reports up to 90% GHG reduction including aftertreatment, per the Ammonia Energy Association. Wärtsilä's upgraded 25 Ammonia, rated 315-345 kW per cylinder for a 1.9-3.1 MW range, is scheduled for commercial deliveries in 2028, and HD Hyundai's HiMSEN H32CDF-LA (max 5.4 MW) obtained approval from seven class societies in October 2025.
Why it matters now
2026 is the year ammonia reached an ocean-going newbuild, yet the regulatory and commercial scaffolding is unfinished. The IMO interim guidelines MSC.1/Circ.1687, approved at MSC 109 in December 2024, set a goal-based framework covering design, bunkering, toxicity mitigation and crew protection, as summarised by UK P&I, with alarm thresholds of 25 ppm for a local alert, 110 ppm for a global alert and 220 ppm for shutdown. DNV considers binding IGF Code amendments unlikely before 2032, so first projects rely on interim guidance, class rules and alternative design approval, according to ClassNK.
Fuel is the second constraint. Green ammonia reached USD 860/t CFR Germany in Q1 2026, the highest recorded European price, per the Ammonia Observatory, and production cost estimates put green at USD 600-1,000/t against USD 300-500/t for grey, per Energy-Solutions.co. Singapore ammonia bunkering remains at feasibility-study stage while methanol licences have been issued since January 2026.
Key players and products
WinGD (X-DF-A), Everllence (formerly MAN Energy Solutions, ME-LGIA) and J-ENG supply two-strokes; Wärtsilä and HD Hyundai supply four-strokes. On the owner side, Exmar took delivery of Antwerpen in June 2026, Eastern Pacific Shipping named the 93,000 m3 VLAC Terra Clove with the first commercial Everllence ME-LGIA in October 2026, and Fortescue, CMB.TECH, Trafigura, NYK and Yara hold the remaining first-mover projects.
Demonstrators came first. Fortescue's converted PSV Green Pioneer, with two of four Cummins engines running ammonia-diesel under DNV technology qualification, ran a seven-week trial in Singapore in March 2024, per MPA Singapore, and underwent the UK's first port-state inspection of an ammonia-fuelled ship in 2025. NYK's tug Sakigake, with IHI engines, confirmed GHG reductions consistently above 90% over three months in Tokyo Bay.
Figures that matter
| Metric | Value | Source type | Source |
|---|---|---|---|
| Ammonia-fuelled vessel orders | 5 through October 2025; 4 in H1 2026 | aggregator | DNV via MarineLink and Argus |
| Ammonia-capable fleet at end-2025 | 3 vessels | aggregator | DNV via Manifold Times |
| WinGD X-DF-A engine orders | about 40 | vendor | WinGD via DieselNet |
| X-DF-A full-load test emissions | N2O below 3 ppm; NH3 slip below 10 ppm; 5% pilot | vendor | WinGD |
| IMO interim guideline alarm thresholds | 25 / 110 / 220 ppm | regulatory | MSC.1/Circ.1687 via Energy-Solutions.co |
| Green ammonia price, Q1 2026 | USD 860/t CFR Germany | aggregator | Ammonia Observatory |
| Production cost, green vs grey | USD 600-1,000/t vs USD 300-500/t | aggregator | Energy-Solutions.co |
Developments 2023-2026
- October 2023: Exmar orders two 46,000 m3 LPG/ammonia carriers at Hyundai Mipo with X52DF-A engines.
- March 2024: Fortescue Green Pioneer completes the first ammonia fuel trial in the Port of Singapore.
- December 2024: IMO approves interim guidelines for ships using ammonia as fuel at MSC 109.
- 2025: Everllence runs the ME-LGIA at 100% load in January; J-ENG completes official tests in August; WinGD installs the first X52DF-A on the Exmar vessel.
- April 2026: The first commercial 6G60ME-LGIA passes its factory acceptance test in South Korea.
- June 2026: Antwerpen is delivered as the world's first ocean-going ammonia-fuelled vessel, first of four; WinGD approves its first X72DF-A for a 210,000 dwt bulker; Fortescue signs with CMB.TECH for up to 12 ammonia-capable bulkers and charters a Bocimar Newcastlemax with an X72DF ammonia engine for end-2026.
- October 2026: EPS names the VLAC Terra Clove at HD Hyundai Heavy Industries Ulsan. Yara Eyde's delivery remains unconfirmed between mid-2026 and 2027.
Outlook
The beachhead is gas carriers and bulkers whose owners already handle ammonia as cargo. Engine-level emissions look solved for two-strokes, but the toxicity-driven safety case, the lack of a binding IGF chapter and the green-grey price spread remain the gating factors, and ordering of four to five ships a year will not change until a global carbon price arrives.
