Lloyd’s Register (LR) has published the maritime industry’s first dedicated Guidance Notes for onboard hydrogen generation, providing long-awaited clarity on the safe design and integration of hydrogen generator technologies on ships.

The new Guidance Notes respond directly to growing interest from shipowners, yards and technology developers in producing hydrogen onboard using alternative fuels such as LNG, methanol and ammonia.

While hydrogen is widely seen as a key fuel for decarbonization, limited supply and availability of complex bunkering infrastructure significantly slow adoption in shipping. In addition, onboard storage may also pose challenges due to space demands and system complexity, adding further barriers to implementation.

Onboard hydrogen generation offers a practical bridge to the future of zero-emission shipping. By producing hydrogen directly on board, shipowners can avoid the need for space-demanding and complex compressed or liquefied hydrogen storage systems and eliminate dependence on the future development of widespread hydrogen supply chains and bunkering infrastructure. At the same time, they position themselves for compliance with tightening emission requirements and future decarbonization regulations.

However, onboard hydrogen generation also presents safety and regulatory challenges due to the presence of two gases or low-flashpoint fuels and the absence of mature international regulations. Drawing on established LR Rules for fuel cells and low-flashpoint fuels, the Guidance Notes provide a clear, risk-based framework that reduces uncertainty, supports plan approval and accelerates project delivery for newbuilds and retrofits.

The Guidance Notes set out practical requirements for the design, safety and onboard installation of hydrogen generators, recognizing the challenges of adapting land-based technologies for the marine environment. By aligning safety principles with existing class requirements, they offer a consistent and credible basis for engagement with flag Administrations and other stakeholders.

For shipowners, yards and technology providers, the Guidance Notes are expected to reduce technical and regulatory uncertainty for projects currently under development, helping to shorten approval timelines and de-risk investment decisions in hydrogen-based solutions.

Thomas Bayer, Lead Specialist Fuel Cell Technology, Technical Directorate, Lloyd’s Register, said, “Clear guidance is essential for emerging technologies. The industry cannot afford to stand still while formal regulations are developed; our Guidance Notes provide the clarity needed to move projects from concept to delivery.

“By publishing dedicated guidance ahead of formal international standards, LR reinforces its position as a trusted advisor on emerging technologies and a leader in supporting the maritime industry’s transition to low- and zero-carbon energy.”