Hydrogen has long been seen as a promising fuel for maritime decarbonisation. In fuel cells, it offers zero tank-to-wake emissions, making it a promising candidate for the sector’s long-term energy transition. But turning this potential into reality is not straightforward. Hydrogen supply infrastructure is limited, storage technically demanding, and regulations evolving. For many operators, the challenge is how to begin deploying hydrogen technologies safely today while preparing for broader adoption in the future.
LR issued its Fuel for Thought: Hydrogen report in January, examining the global hydrogen market, technology readiness, and operational realities shaping adoption in shipping. LR recognises the challenges surrounding hydrogen use and the emerging opportunities for onboard hydrogen generation, whether as a transitional measure or a long‑term solution. Guidance Notes for Onboard Hydrogen Generation give practical, structured recommendations for safely integrating onboard hydrogen generation systems. Together, these documents combine strategic insight and technical guidance to accelerate the safe, responsible uptake of hydrogen and fuel cell technology in maritime operations.
Practical constraints
LR’s Fuel for Thought: Hydrogen shows hydrogen adoption to be limited by a combination of undeveloped infrastructure, and technical and economic factors. Less than one percent of global hydrogen production comes from low-emissions sources, and storing liquid hydrogen at least –253°C constrains vessel design and limits the fuel’s immediate applicability.
These realities constrain initial projects to short-sea and fixed-route operations, where predictable refuelling, policy support, and access to renewable energy enable operators can overcome storage and supply challenges. Examples include Norwegian hydrogen ferries and Swiss passenger vessels, where policy incentives and regional infrastructure support early adoption.
LR’s report findings show that the industry needs transitional solutions to advance operational experience and to develop supply chains before large-scale bunkering infrastructure becomes widely available.
Onboard hydrogen generation
One of the most effective transitional solutions is onboard hydrogen generation. By producing hydrogen from alternative fuels such as methanol or ammonia directly onboard, vessels can use fuel cells without depending on extensive hydrogen bunkering or large storage tanks.
Hydrogen introduces a combination of hazards that require careful management. Its wide flammability range, low ignition energy, and low density pose specific risks in confined shipboard environments. Onboard generation adds complexity: vessels will carry both the primary fuel and the resulting hydrogen, each with different dispersion and ignition characteristics.
The report finds onboard generation as a potential bridge strategy for shipowners to develop operational experience, build hydrogen-ready architectures, yet sustain flexibility for future fuel pathways. Onboard generation from other fuel sources also introduces the possibility of longer-term operations, using carbon-neutral fuels such as green methanol, to enable near-zero or net-zero emissions without waiting for large-scale hydrogen production to mature.
Recognising this potential, LR developed and issued the maritime industry’s first dedicated Guidance Notes for Onboard Hydrogen Generation in February. These Guidance Notes were developed from LR’s established Rules and Regulations for the Classification of Ships using Gases or other Low-flashpoint Fuels and the Rules for fuel cell power installations, complemented by the extensive practical experience gained through numerous practical projects. The notes give practical, risk-based guidance to support designers, yards, operators, and flag administrations in the safe integration of onboard hydrogen generators.
Regulatory clarity
Regulatory frameworks have not yet caught up with advancing hydrogen technologies. Interim International Maritime Organization (IMO) guidelines for hydrogen as a fuel are progressing. But there are currently no prescriptive requirements for onboard hydrogen generation, and this uncertainty risks discouraging early adopters.
LR’s Guidance Notes fill this gap, enabling projects to proceed safely and confidently. LR’s experience, established safety frameworks, and international regulations give hydrogen stakeholders a pathway to demonstrate that novel hydrogen systems meet an equivalent level of safety to established marine fuel installations.
This approach accelerates deployment and mitigates the risks of fragmented interpretations, inconsistent approvals, and should reduce regulatory delays so hydrogen technologies scale safely beyond pilot projects.
Structured assurance framework
To manage both hydrogen and the primary fuel onboard, LR’s Guidance Notes recommend risk-based methodologies to identify hazards, design systems, and assure operations. Risk-based approaches encourage a structured cross-system analysis for clearly defined hazardous zones, the design of ventilation, gas detection, and verification procedures. LR’s ShipRight Risk-Based Certification is the framework for evaluating novel systems, to make sure evidence supports any safety claim.
This structured approach maintaining safety while allows innovation and gives shipowners, designers, and regulators the confidence to adopt hydrogen solutions without waiting for prescriptive rules.
LR applied this same methodology to a range of real-world projects including multi-megawatt fuel cell power installations on liquid-hydrogen (LH₂) cruise ship concepts, hybrid LH₂-powered superyachts, gaseous-hydrogen ferries, and harbour craft such as tugs. Each project gives wider insights into system integration, operational challenges, and safety performance.
LR’s Guidance Notes distil these early experiences into practical guidance, so new projects benefit from lessons learned. Over time, this will reduce uncertainty, streamline approvals, and lower industry costs across the industry from standardised hydrogen system designs.
The maritime transition to zero-carbon energy will be gradual, combining multiple fuels, technologies, and operational strategies. Hydrogen has a central role, but its successful adoption depends on credible safety frameworks, regulatory clarity, and practical guidance.
By combining strategic insight with structured, risk-based guidance, LR enables the industry to move from ambition to action. Onboard hydrogen generation is a pragmatic route to early deployment, giving operators a way to gain experience, and designers to develop hydrogen-ready solutions aligned to long-term decarbonisation goals.
As early projects mature, the lessons learned will help shape future standards, reduce uncertainty and support wider adoption across vessel types and operating profiles.
