- Shipping faces unique challenges in decarbonization, but hydrogen and ammonia are emerging as leading low-emission fuel options.
- Pilot projects, regulatory frameworks, and technology developments are laying the groundwork for wider adoption, though no oceangoing vessels yet operate solely on these fuels.
- Safety risks, regulatory uncertainty, and crew training remain key hurdles, requiring coordinated industry-wide efforts to enable scaling.
The energy transition is advancing rapidly across sectors, but shipping has proven harder to decarbonize. Between 2015 and 2024, electric vehicle sales grew from less than 1% to 22% of new cars, while solar’s share of global power generation increased sixfold. In contrast, ships — capital-intensive assets designed to last decades and subject to strict safety rules — cannot switch fuels as easily. For shipowners, adopting new fuel technologies is less a short-term upgrade than a long-term strategic commitment shaped by regulation, infrastructure, and financial risk, according to Hanhwa.
Why Hydrogen and Ammonia Matter Now
The International Maritime Organization (IMO) has set ambitious emissions targets: reducing greenhouse gases 20% by 2030, 70% by 2040, and achieving net-zero by 2050 compared with 2008 levels. These milestones cannot be met through efficiency gains alone, making lower-emission fuels essential. Hydrogen and ammonia stand out because both enable carbon-free tank-to-wake operations with minimal air pollutants. Their relevance is increasing under tightening emissions rules, growing investor pressure, and the need to future-proof fleets against rising compliance costs.
Early Steps Toward Adoption
Hydrogen and ammonia are beginning to enter shipping through dual-fuel vessel designs, giving operators flexibility as infrastructure develops. Hydrogen is being trialed on smaller vessels such as ferries and tugs, often using fuel cells, while ammonia is under evaluation for larger ships including bulk carriers and gas carriers. Although adoption remains at an early stage, momentum is growing as regulatory frameworks evolve and engine manufacturers advance hydrogen- and ammonia-compatible designs. Dozens of ammonia-fueled vessels are under construction or certified as “ammonia-ready,” and class societies like DNV are introducing interim rules to streamline approval. In March 2025, Hanwha Aerospace, for instance, secured approval in principle from DNV for its marine hydrogen fuel cell system — highlighting the progress being made.
Managing Safety Risks
Hydrogen and ammonia pose distinct safety challenges at sea, requiring specialized containment, vessel adaptations, and trained crews. Hydrogen, with its high flammability, low ignition threshold, and storage needs at either cryogenic temperatures or high pressure, demands advanced safety systems to manage risks like leakage, boil-off gas, and fire hazards. Ammonia, by contrast, is less flammable but highly toxic and corrosive, requiring ventilation systems, strict bunkering protocols, resistant materials, and carefully designed evacuation routes. In both cases, the maritime context — limited space, complex operations, and short response times — makes safety standards and crew preparedness paramount.
What Will Drive Widespread Adoption
For hydrogen and ammonia to scale, the industry needs regulatory certainty, technological maturity, vessel integration, and skilled workforce development, underpinned by cross-sector collaboration. One of the biggest hurdles is regulation: neither fuel is yet included in the IMO’s International Code of Safety for Ships Using Gases or Other Low-flashpoint Fuels (IGF Code). Until at least 2028, projects must rely on a risk-based Alternative Design Approval process, requiring proof of equivalent safety. Interim class rules, such as those issued by DNV, are helping to bridge the gap. Beyond regulation, ship design will need to evolve to accommodate larger fuel tanks and advanced safety systems, while seafarers will require new training tailored to the unique risks of these fuels. Until global standards are in place, custom programs developed with flag states and class societies will remain critical.
Although no oceangoing vessels yet operate solely on hydrogen or ammonia, the foundations for adoption are steadily forming. Pilot projects, interim regulations, and advancing engine technologies point to a path forward, but overcoming safety, design, and regulatory challenges will demand close collaboration across the maritime value chain. With pressure mounting to meet IMO’s climate targets, hydrogen and ammonia are poised to play a central role in the sector’s long-term decarbonization strategy.
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Source: Hanhwa
