Japan-based classification society ClassNK has released updated guidance on EU environmental regulations, publishing the “FAQs on the EU-ETS for Shipping (3rd Edition)” and “FAQs on the FuelEU Maritime (5th Edition)”.
The updates explain procedures for applying newly introduced actual methane slip emission factors when LNG is used as fuel.
The European Commission expanded the EU Emissions Trading System to maritime in 2023, with application from 1 January 2024. Meanwhile, FuelEU Maritime entered into force in October 2023 and has applied since 1 January 2025.
Both frameworks cover ships above 5,000 gross tonnage calling at EU ports.
Under the rules, LNG-fuelled vessels may use measured methane slip values instead of default emission factors. Depending on engine type, measured values may be lower, potentially reducing calculated greenhouse gas emissions under both EU-ETS and FuelEU Maritime.
The new FAQs clarify how to apply measured Tank-to-Wake methane slip emission factors in line with European Commission guidelines issued in October 2025.
ClassNK said it will continue supporting industry stakeholders through its “ClassNK Transition Support Services”.
