The Bahamas, Liberia and several industry organisations have proposed revising the IMO’s Carbon Intensity Indicator (CII) reference lines to focus on fuel consumption while ships are sailing at sea.
In document submitted to the IMO's Marine Environment Protection Committee (MEPC), the co-sponsors argue that fuel consumed when ships are not sailing can materially affect CII ratings and may not accurately reflect operational efficiency.
The CII measures a ship's annual carbon intensity based on its CO2 emissions relative to its transport work, assigning it a rating from A to E. It forms part of the IMO's short-term greenhouse gas reduction measures.
The co-sponsors argue that fuel consumed when ships are not sailing, including during port stays and canal passages, can materially affect ratings and may not accurately reflect operational efficiency at sea.
Enhanced IMO data collection system (DCS) reporting requirements, which distinguish between fuel consumption while ships are under way and not under way, became mandatory in January 2026. The first dataset will be submitted to the IMO database in 2027.
The proposal calls for using 2026 data to reassess CII reference lines, which were originally developed using total reported fuel consumption.
It also recommends reviewing existing correction factors and voyage adjustments, particularly those relating to port operations, if fuel consumed when ships are not under way is excluded from calculations.
The co-sponsors have called for an assessment of the impact on different ship types, size segments and CII ratings before revised reference lines are adopted.
