Lloyd’s Register (LR) has published the maritime industry’s first dedicated guidance notes for onboard hydrogen generation systems, addressing a regulatory gap as shipowners explore alternatives to hydrogen bunkering infrastructure.

The guidance notes, designated LR-GN-061, provide technical requirements for the design, installation and integration of hydrogen generators that produce the fuel onboard from sources including LNG, methanol and ammonia.

According to LR, onboard hydrogen generation has attracted interest from shipowners, shipyards and technology developers as a way to avoid dependence on hydrogen supply chains and bunkering infrastructure, which remain limited. The approach also eliminates the need for compressed or liquefied hydrogen storage systems, which can be space-intensive and complex.

However, the technology presents safety challenges due to the presence of two gases or low-flashpoint fuels onboard, and the absence of mature international regulations covering the systems.

The guidance notes draw on LR’s existing rules for fuel cells and low-flashpoint fuels to provide a risk-based framework for plan approval and project delivery for both newbuilds and retrofits.

Thomas Bayer, lead specialist for fuel cell technology at LR’s technical directorate, 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.”

The guidance notes align safety principles with existing class requirements to provide a basis for engagement with flag administrations and other stakeholders. LR said the document is expected to reduce technical and regulatory uncertainty for projects under development and help shorten approval timelines.

The publication follows LR’s recent report examining hydrogen’s role in maritime decarbonisation, which assessed the fuel’s advantages alongside safety, infrastructure and cost challenges currently restricting adoption.

The guidance notes are available through LR’s website.