Bahamas and Liberia seek CII overhaul to focus ship ratings on fuel used at sea

The Bahamas, Liberia and five shipping industry organisations have proposed recalibrating the International Maritime Organization’s (IMO) Carbon Intensity Indicator (CII) reference lines to focus on fuel consumed while vessels are under way. Submitted for consideration at the Marine Environment Protection Committee’s 85th session (MEPC 85), the proposal seeks to reduce the influence of port stays and waiting time on ship efficiency ratings.

The submission, numbered MEPC 85/6/11, brings together the two flag states, shipping association BIMCO, the International Chamber of Shipping, tanker owners’ association INTERTANKO, dry cargo shipowners’ association INTERCARGO and the International Bunker Industry Association. It remains a proposal, with no revised reference lines adopted.

Why are shipping organisations seeking changes?

BIMCO argues that the current framework can reflect trading conditions rather than a vessel’s operational efficiency. Fuel consumed at anchor or alongside contributes to emissions, while the distance component of the calculation does not increase during those periods.

This affects ships differently. Short-sea services typically involve more frequent port calls, while congestion and terminal limitations can prolong waiting times. The co-sponsors want the assessment to distinguish these circumstances more clearly from performance during sea passages.

How would the CII reference lines change?

The proposal recommends analysing enhanced fuel-consumption data for 2026 before recalibrating the benchmarks. That dataset will reach the IMO database in 2027.

The co-sponsors also seek an assessment of how changes would affect different ship types, size categories and the distribution of ratings. Existing correction factors and voyage adjustments, particularly those associated with port operations, would need review if consumption outside sea passages were excluded.

The present reference lines use ships’ operational carbon-intensity performance in 2019. Separate benchmarks apply to different vessel types, incorporating capacity so that comparisons are made between comparable ships. They were established using data submitted through the IMO’s fuel-consumption reporting system.

BIMCO cautions that removing selected fuel consumption without adjusting those benchmarks would create an inconsistent comparison. It also stresses that emissions during port stays and anchorage should remain recorded, even if their treatment within CII ratings changes.

What additional fuel data is available?

More detailed reporting under the IMO Data Collection System (DCS) became mandatory for the 2026 reporting period, following voluntary implementation from 2025.

The additional information includes fuel consumption by main engines, auxiliary engines and boilers, consumption while a vessel is not under way, transport work and shore-power use. These fields provide a more detailed account of how energy is consumed across ship operations.

Under the established reporting process, annual information first goes to the flag state for verification. The flag state subsequently transfers the data to the IMO database by 30 June. The organisation uses aggregated information to prepare reports for its environmental committee.

What does the review mean for shipowners?

CII reporting began in 2023, with the first annual ratings issued in 2024. The framework applies to covered vessels of 5,000 gross tonnage and above and assigns ratings from A to E, with A representing the strongest performance.

A vessel rated D for three consecutive years, or E for one year, must submit a corrective action plan explaining how it will achieve C or better. The calculation methodology therefore has practical implications for fleet management and compliance planning.

The proposed recalibration sits within the second phase of the IMO’s review of its short-term greenhouse gas reduction measures. That phase runs from spring 2026 to spring 2028 and includes further development of efficiency metrics and the Ship Energy Efficiency Management Plan framework. Existing requirements continue while the review proceeds.