BIMCO co-sponsors proposal to focus CII on fuel consumption while ships are under way

The proposal, submitted to the 85th session of the Marine Environment Protection Committee (MEPC 85), is co-sponsored by the Bahamas, Liberia, BIMCO, the International Chamber of Shipping (ICS), INTERTANKO, INTERCARGO and the International Bunker Industry Association (IBIA). 

Under the current CII regulations, all fuel consumption contributes to a ship's attained CII, including fuel consumed while a ship is not under way, eg, at anchorage or moored in a port. However, the transport work used in the CII calculation is linked to the distance the ship travels. This means that fuel consumed during periods when a ship is not progressing on its voyage will worsen its CII rating. 

This can have very different consequences depending on how and where a ship operates. Ships engaged in short sea trades generally make more port calls than ships on long-haul trades. Congestion can leave ships waiting at anchor for prolonged periods, while the duration of port stays can depend on the efficiency and limitations of ports and terminals. These differences affect CII ratings without having any link to a ship’s capability. The rating becomes a trade rating rather than a ship rating. 

For BIMCO, the objective is not to disregard emissions that occur while ships are in ports or waiting at anchorages. These emissions remain important and should continue to be captured through the IMO Data Collection System (DCS), providing a complete picture of the sector's fuel consumption and emissions. 

Instead, the question is whether the CII rating can provide a more meaningful measure of a ship's operational energy efficiency and create the right incentives to reduce emissions. 

More granular IMO data provides an opportunity to improve CII 

The proposal builds on several steps already agreed at the IMO to improve the data available through the IMO DCS. 

At MEPC 81 in 2024, the IMO adopted amendments to MARPOL Annex VI that significantly increased the level of detail ships must report to the IMO DCS. This included a new requirement to report fuel consumption while ships are not under way, broken down by fuel and consumer type. The amendments entered into force on 1 August 2025.  

The IMO subsequently established common definitions to ensure consistent reporting to the IMO DCS. At MEPC 83 in 2025, “under way” was defined, using existing definitions in the IMO Compendium on facilitation and electronic business (IMO Compendium), as the period between full ahead on passage and the end of sea passage. “Not under way” consequently covers the period between the end of sea passage and full ahead on passage. Canal passages are also treated as not under way because they can involve frequent manoeuvring, acceleration and deceleration. 

At MEPC 84 in 2026, the IMO further clarified how distance travelled should be reported in the Ship Energy Efficiency Management Plan (SEEMP) guidelines. 

Together, these decisions mean that the IMO will have a more detailed global data set that distinguishes fuel consumption while ships are under way from fuel consumption while they are not under way. The DCS data for the calendar year 2026 will therefore provide a new basis for considering how the distinction could be reflected in the CII regulations. 

Using the new data to reassess CII 

The proposal invites the IMO to use the enhanced 2026 data to reassess and recalibrate the CII reference lines, focusing on fuel consumption while ships are under way. 

This is an important step. The existing CII reference lines were developed using data that included all reported fuel consumption. Simply excluding fuel consumed while ships are not under way without recalibrating the reference lines would therefore not provide a consistent basis for establishing CII ratings. 

The submission does not predetermine what revised reference lines should look like. Instead, BIMCO and the other co-sponsors call for a comprehensive data analysis before revised reference lines are developed. 

The analysis would assess changes in attained CII values across different ship types and size segments and the resulting distribution of A to E ratings. It should also identify whether changes could result in unintended market distortions or unequal treatment of comparable ships of the same type and trade. 

Considering correction factors and voyage adjustments 

The proposal also recognises that focusing CII on fuel consumption while ships are under way could affect existing correction factors and voyage adjustments. 

Some corrections linked to port operations may no longer be needed if fuel consumed while ships are not under way is excluded from the calculation. Other correction factors may need to be amended to account for the different operational characteristics of ships, trades and operating profiles. 

Any recalibration should improve fairness and better reflect actual efficiency while under way. It should also be practical and verifiable, avoid unintended consequences and not increase the administrative burden for shipowners and ship managers. 

Improving efficiency across the shipping value chain 

Separating fuel consumption while not under way from a ship's CII rating should not reduce the incentive to address emissions associated with waiting and port calls. 

Reducing these emissions requires co-operation across the shipping value chain. Better port call optimisation, including just-in-time arrival, can convert unnecessary waiting time into sailing time, allowing ships to optimise speed and reduce fuel consumption. This is an area BIMCO has worked on for many years, including through its contractual solutions supporting just-in-time arrival, virtual arrival and port call data exchange. 

The proposal therefore stresses the importance of encouraging ports and terminals to optimise port calls. The decision to implement such measures can typically only be taken by a port or terminal operator, but the measures can improve the efficiency of ship operations both while under way through speed optimisation and while not under way through reduced time at anchor. 

What happens next? 

MEPC 85 will consider the proposal as part of phase 2 of the review of the IMO's short-term GHG reduction measure. 

The IMO started phase 2 at MEPC 84 and has already recognised the merits of further exploring alternative CII metrics, including the possibility of limiting CII calculations to fuel consumption while ships are under way. 

BIMCO will continue to support a review of the CII regulations based on robust data and practical solutions that can help the CII better reflect a ship’s actual operational efficiency.