Case study: Ammonia as shipping fuel & hydrogen carrier — a startup-to-enterprise scale story

The International Maritime Organization's revised greenhouse gas strategy calls for net-zero emissions from international shipping by around 2050, and ammonia has emerged as the leading candidate fuel to decarbonize the sector's 1.1 billion tonnes of annual CO2 emissions (IMO, 2025). Yet fewer than 15% of ammonia-fueled shipping ventures that secured seed or Series A funding between 2019 and 2023 have advanced to enterprise-scale operations involving more than five commercial vessel deployments (Lloyd's Register, 2025). This case study traces how three pioneering companies navigated the journey from pilot demonstrations to commercial-scale ammonia fuel and hydrogen carrier operations, revealing the engineering milestones, regulatory challenges, and partnership strategies that separated scalable ventures from those that stalled at the demonstration phase.

Why It Matters

International shipping transports approximately 90% of global trade by volume, and the sector's reliance on heavy fuel oil and marine gas oil makes it one of the most carbon-intensive transportation modes per tonne-kilometre. The IMO's 2023 revised strategy introduced indicative checkpoints: a 20% reduction in greenhouse gas intensity by 2030 and a 70% reduction by 2040, both measured against a 2008 baseline. These targets are driving fleet operators, charterers, and fuel suppliers to evaluate zero-carbon alternatives at an unprecedented pace.

Ammonia presents a compelling proposition: it contains no carbon, has an energy density of 12.7 MJ/L (compared to 36 MJ/L for heavy fuel oil), and can be transported and stored using established infrastructure adapted from the global fertilizer industry, which already moves approximately 20 million tonnes of ammonia annually. For policy and compliance professionals operating in the UK maritime sector, the regulatory landscape is intensifying. The UK Maritime and Coastguard Agency issued updated guidance in 2025 on ammonia fuel handling, bunkering safety protocols, and crew training requirements, while the UK Shipping Office for Reducing Emissions (UK SHORE) allocated GBP 206 million to clean maritime technology development including ammonia propulsion (UK Department for Transport, 2025).

Understanding which ammonia fuel ventures have successfully scaled provides critical intelligence for compliance planning, fuel procurement strategy, and long-term fleet investment decisions.

Key Concepts

Green ammonia is produced by combining green hydrogen (generated through electrolysis powered by renewable energy) with nitrogen separated from air using the Haber-Bosch process or emerging electrochemical synthesis methods. Green ammonia eliminates the CO2 emissions associated with conventional grey ammonia production, which relies on natural gas as both feedstock and energy source and generates approximately 1.8 tonnes of CO2 per tonne of ammonia produced.

Ammonia-fueled engines are internal combustion engines or fuel cells adapted to use ammonia as a primary fuel. Two-stroke ammonia engines developed by MAN Energy Solutions and WinGD use a pilot fuel injection of approximately 5% conventional fuel to initiate combustion, with the remaining 95% of energy derived from ammonia. Ammonia fuel cells, primarily solid oxide fuel cells (SOFCs), convert ammonia directly to electricity without combustion, offering higher theoretical efficiency but lower technological readiness.

Ammonia cracking is the process of decomposing ammonia into hydrogen and nitrogen at temperatures between 400 and 900 degrees Celsius. This enables ammonia to serve as a hydrogen carrier: ammonia can be transported in bulk at moderate refrigeration (minus 33 degrees Celsius) and then cracked at the destination to produce hydrogen for fuel cells, industrial processes, or power generation.

Bunkering infrastructure refers to the facilities, equipment, and logistics systems required to supply fuel to vessels at port. Ammonia bunkering requires specialized handling due to ammonia's toxicity (the IDLH concentration is 300 ppm) and requires double-walled piping, gas detection systems, exclusion zones, and trained personnel.

What's Working

Amogy: From Drone Demonstration to Tugboat-Scale Ammonia Power

Amogy, founded in Brooklyn, New York, in 2020, developed a compact ammonia cracking and fuel cell system that converts ammonia to hydrogen on-board and feeds it to proton exchange membrane (PEM) fuel cells for electric propulsion. The company's scaling trajectory moved through four distinct demonstrations in rapid succession: a 5 kW drone in 2022, a 100 kW tractor in 2023, a 300 kW semi-truck in 2023, and a 1 MW maritime system installed on the tugboat NH3 Kraken in 2024. Each stage validated cracking efficiency, thermal management, and system integration at progressively larger power outputs (Amogy, 2025).

The NH3 Kraken demonstration, conducted on a retrofitted tugboat in upstate New York, proved ammonia-to-power conversion at maritime scale with a system-level efficiency of approximately 42%, competitive with diesel-electric propulsion when accounting for the carbon cost of conventional fuels. Amogy raised $270 million in total funding through 2025, including a $150 million Series C led by SK Innovation and Amazon's Climate Pledge Fund. The company's enterprise transition involved securing engineering partnerships with Hanwha Ocean for vessel integration and memoranda of understanding with three shipping operators for multi-vessel deployments beginning in 2026.

The critical scaling lesson from Amogy was the value of rapid, incremental demonstrations. Each power-level milestone generated engineering data that de-risked the next stage and provided investors with tangible proof of progress, reducing due diligence timelines from an average of 8 months at the seed stage to 4 months at Series C.

MAN Energy Solutions: Retrofitting the Global Fleet with Ammonia Two-Stroke Engines

MAN Energy Solutions, headquartered in Copenhagen, represents the enterprise end of the scaling spectrum. As the world's largest manufacturer of large-bore marine engines, MAN committed in 2020 to delivering ammonia-fueled two-stroke engines commercially by 2025. The company's B&W ME-LGIP (Liquid Gas Injection, ammonia variant) engine completed factory acceptance testing in late 2024, achieving NOx and N2O emissions below IMO Tier III limits using selective catalytic reduction and a proprietary combustion chamber geometry (MAN Energy Solutions, 2025).

MAN's go-to-market strategy leveraged its installed base of more than 21,000 two-stroke engines in the global fleet. The company offered ammonia fuel conversion kits for existing ME-C series engines, reducing the capital cost of ammonia adoption from the $15 million to $25 million required for a newbuild ammonia-ready vessel to approximately $3 million to $8 million for a retrofit. By Q1 2025, MAN had received confirmed orders for 27 ammonia-fueled engines across newbuild container ships, bulk carriers, and tankers, with first deliveries scheduled for 2026 (MAN Energy Solutions, 2025).

For UK-based fleet operators subject to the UK Emissions Trading Scheme expansion to maritime (proposed for implementation by 2028), MAN's retrofit pathway provides a compliance strategy that avoids the 20 to 25 year asset write-down associated with premature vessel retirement.

Yara Clean Ammonia: Building the Bunkering Supply Chain from Producer to Port

Yara International, the world's largest ammonia producer with 8 million tonnes of annual capacity, established Yara Clean Ammonia as a dedicated subsidiary in 2022 to build the green ammonia supply chain for maritime fuel. The subsidiary's scaling strategy addressed the supply-side challenge that complements engine and cracking technology development. Yara secured green ammonia production capacity through its 24 MW Heroya electrolyser in Norway (operational since 2023), partnerships with ACME Group for a 1.2 million tonne per year facility in Oman, and offtake agreements with green ammonia producers in Australia and Chile (Yara, 2025).

On the bunkering side, Yara Clean Ammonia partnered with the Port of Rotterdam, Port of Singapore, and Felixstowe in the UK to develop ammonia bunkering terminals. The Felixstowe project, announced in 2024 with support from UK SHORE funding, targets initial bunkering capacity of 200,000 tonnes per year by 2027, sufficient to fuel approximately 150 deep-sea vessel voyages annually. Yara's integrated approach, controlling production, logistics, and bunkering, reduced fuel price uncertainty for early-adopter shipping lines. The company's enterprise ammonia fuel supply contracts offered fixed-price corridors of $600 to $900 per tonne for green ammonia, compared to spot market volatility of $400 to $1,200 per tonne during 2024 (Argus Media, 2025).

What's Not Working

Ammonia toxicity and safety perception remains the single largest barrier to rapid fleet adoption. Ammonia's acute toxicity at relatively low concentrations (IDLH of 300 ppm, compared to 50,000 ppm for methane) creates regulatory and public acceptance challenges that hydrogen and methanol do not face to the same degree. The Singapore Maritime and Port Authority suspended an ammonia bunkering trial in 2024 after local community opposition, delaying the port's ammonia readiness timeline by 18 months. Classification societies including Lloyd's Register and DNV have published provisional rules for ammonia-fueled vessels, but flag state adoption of these rules varies significantly, creating regulatory fragmentation that increases compliance costs for international operators.

N2O slip from ammonia combustion is an emerging emissions challenge that threatens the fuel's climate credentials. Nitrous oxide (N2O) has a global warming potential 273 times that of CO2 over a 100-year horizon. Early engine testing revealed N2O emissions of 2 to 8 grams per kilowatt-hour under partial load conditions, which at the upper range could offset 30 to 40% of the CO2 emissions benefit of switching from heavy fuel oil. Engine manufacturers are developing catalytic aftertreatment systems to address N2O slip, but validated solutions for large-bore marine engines are not yet commercially available at scale (Lloyd's Register, 2025).

Green ammonia cost premiums persist at levels that make unsubsidized adoption challenging. Green ammonia production costs in 2025 ranged from $700 to $1,100 per tonne, compared to $250 to $400 per tonne for grey ammonia. On an energy-equivalent basis, green ammonia fuel costs are approximately 3 to 5 times higher than heavy fuel oil. Without carbon pricing mechanisms set at $150 per tonne of CO2 or higher, voluntary adoption relies on corporate decarbonization commitments and regulatory mandates rather than pure cost competitiveness.

Crew training and workforce readiness has lagged behind technology development. The International Convention on Standards of Training, Certification and Watchkeeping (STCW) does not yet include ammonia-specific competency requirements. Individual flag states and classification societies have issued interim guidance, but the absence of a harmonized international training standard creates uncertainty for fleet operators managing multinational crews. UK-based maritime training providers report that demand for ammonia handling courses has tripled since 2023, but standardized curricula remain under development by the Maritime and Coastguard Agency.

Key Players

Established Companies

• MAN Energy Solutions: world's largest two-stroke marine engine manufacturer, delivering commercial ammonia-fueled engines from 2025
• Yara International: world's largest ammonia producer, building green ammonia supply chains and bunkering infrastructure through Yara Clean Ammonia
• WinGD (Winterthur Gas & Diesel): Swiss-headquartered engine manufacturer developing the X-DF-A ammonia-fueled two-stroke engine for deep-sea vessels
• Samsung Heavy Industries: South Korean shipbuilder constructing ammonia-ready newbuild vessels with integrated fuel storage and safety systems

Startups

• Amogy: Brooklyn-based developer of compact ammonia cracking and fuel cell systems for maritime and heavy-duty transport
• Fortescue (FFI subsidiary): developing large-scale green ammonia production and ammonia-fueled vessel conversions through the Green Pioneer program
• Azane: Norwegian startup building modular ammonia bunkering terminals for ports transitioning to ammonia fuel supply
• TECO 2030: Norwegian clean technology company developing ammonia fuel cell systems for marine applications

Investors and Funders

• SK Innovation: South Korean energy company and lead investor in Amogy's $150 million Series C round
• Amazon Climate Pledge Fund: invested in ammonia propulsion technology as part of scope 3 shipping decarbonization strategy
• UK SHORE (Shipping Office for Reducing Emissions): government funding body allocating GBP 206 million to clean maritime technology including ammonia propulsion

Action Checklist

• Assess fleet exposure to upcoming UK and EU maritime emissions regulations by cataloguing vessel ages, fuel types, and remaining economic life to identify candidates for ammonia retrofit
• Engage with classification societies (Lloyd's Register, DNV) to understand provisional ammonia fuel rules applicable to your flag state and vessel class
• Evaluate ammonia fuel supply options by requesting indicative pricing from Yara Clean Ammonia and other suppliers for your primary bunkering ports, including Felixstowe and Rotterdam
• Develop crew training plans for ammonia handling by enrolling senior officers in available ammonia safety and bunkering courses, anticipating STCW updates within 24 months
• Commission a lifecycle emissions analysis covering well-to-wake greenhouse gas emissions for ammonia fuel, including N2O slip under realistic operating profiles, before committing to ammonia as your primary decarbonization pathway
• Structure pilot agreements with engine OEMs for single-vessel ammonia conversion, establishing 12 to 18 month evaluation periods with defined performance and safety benchmarks
• Participate in port-level ammonia readiness working groups at your primary bunkering locations to influence infrastructure development timelines and safety protocol harmonization

FAQ

Q: How does ammonia compare to methanol as a shipping fuel in terms of scalability and emissions? A: Ammonia contains no carbon, eliminating CO2 emissions at the point of combustion, while methanol (even green methanol from biomass or captured CO2) still produces CO2 when burned and relies on carbon accounting to claim carbon neutrality. On the supply side, global ammonia production infrastructure is more developed (180 million tonnes per year) than green methanol production (under 1 million tonnes per year in 2025). However, methanol is less toxic, compatible with existing fuel handling procedures, and does not produce N2O emissions. Many fleet operators are pursuing methanol as a transitional fuel while ammonia safety standards and supply chains mature.

Q: What is the realistic timeline for ammonia bunkering availability at major UK ports? A: The UK SHORE-funded Felixstowe ammonia bunkering terminal targets initial operations by 2027 with 200,000 tonnes per year capacity. The Port of Immingham is conducting feasibility studies for ammonia bunkering linked to the Humber industrial cluster's green hydrogen and ammonia production plans. Realistically, UK-based fleet operators should expect limited ammonia bunkering at one to two major ports by 2028, with broader availability at five or more ports by 2030 to 2032, contingent on green ammonia production scaling and port safety permitting timelines.

Q: What are the key safety requirements for operating ammonia-fueled vessels in UK waters? A: The UK Maritime and Coastguard Agency requires compliance with the IMO's Interim Guidelines for the Safety of Ships Using Ammonia as Fuel (MSC.1/Circ.1621), which mandate double-walled fuel piping, gas detection systems with alarm thresholds at 25 ppm, enclosed fuel preparation rooms with forced ventilation, personal protective equipment including self-contained breathing apparatus for all crew, and emergency ammonia release drills at monthly intervals. Vessel-specific safety assessments approved by a recognized classification society are required before any ammonia-fueled vessel operates in UK territorial waters.

Q: How much does it cost to retrofit an existing vessel for ammonia fuel? A: Retrofit costs vary by vessel type and engine configuration. For a two-stroke engine conversion using MAN's ammonia fuel kit on an existing ME-C series engine, costs range from $3 million to $8 million including fuel tank installation, piping modifications, safety systems, and classification society approval. Newbuild ammonia-ready vessels carry a premium of $15 million to $25 million over conventional equivalents. Financing support through green shipping bonds and UK SHORE grants can offset 20 to 30% of retrofit capital costs for qualifying operators.

Sources

• International Maritime Organization. (2025). 2023 IMO Strategy on Reduction of GHG Emissions from Ships: Implementation Update. London: IMO.
• Lloyd's Register. (2025). Zero-Carbon Fuel Monitor: Ammonia as Marine Fuel, Technical and Regulatory Assessment. London: Lloyd's Register Group.
• MAN Energy Solutions. (2025). ME-LGIP Ammonia Engine: Technical Specifications and Commercialization Roadmap. Copenhagen: MAN Energy Solutions SE.
• Amogy Inc. (2025). Ammonia-to-Power for Maritime Decarbonization: Technology and Deployment Update. Brooklyn, NY: Amogy Inc.
• Yara International. (2025). Yara Clean Ammonia: Green Ammonia Supply Chain and Bunkering Infrastructure Progress Report. Oslo: Yara International ASA.
• Argus Media. (2025). Global Ammonia Market Outlook: Pricing, Trade Flows, and the Maritime Fuel Transition. London: Argus Media Ltd.
• UK Department for Transport. (2025). UK SHORE Programme: Clean Maritime Technology Investment Summary. London: Department for Transport.