The International Bunker Industry Association (IBIA) has submitted document MEPC 85/6/4 to the IMO, urging a change to the Carbon Intensity Indicator (CII) calculation for conventional bunker vessels so that it applies only when vessels are “under way.” IBIA argues that bunker vessels are inherently constrained by short voyages and in-port manoeuvring, while recent data-reporting changes under MARPOL Annex VI now make it possible to separately account for under-way operations. The association says the approach could help address CII impacts arising from operational factors beyond ship operators’ control.
London, UK | September 11, 2026 – The International Bunker Industry Association (IBIA) has asked the International Maritime Organization (IMO) to change how the Carbon Intensity Indicator (CII) is calculated for conventional bunker vessels, proposing that the calculation should apply only when a vessel is “under way.”
In submission MEPC 85/6/4, prepared by IBIA Representative Dr. Edmund Hughes, the association argues that the operational characteristics of bunker vessels, particularly their short voyages and frequent in-port manoeuvring, can create challenges under the existing CII framework. IBIA says recent changes to IMO data-reporting requirements now make it possible to distinguish between a vessel’s “under way” and “not under way” operations when calculating its carbon intensity.
The proposal will be considered in the context of the IMO’s ongoing review of short-term greenhouse gas (GHG) reduction measures.
IMO CII Framework Under Review
At MEPC 83, the IMO adopted resolution MEPC.400(83), amending the 2021 Guidelines on operational carbon intensity reduction factors relative to reference lines, known as the CII reduction factors guidelines (G3).
The amended guidelines establish the methodology for determining annual operational carbon intensity reduction factors and set the applicable reduction factors for 2023 to 2030 under regulation 28 of MARPOL Annex VI. The amendments adopted at MEPC 83 also introduced CII reduction factors for the 2027–2030 period.
MEPC 83 also agreed on a work plan for phase 2 of the review of short-term GHG reduction measures, covering the period from spring 2026 to spring 2028. The second phase includes work to enhance the Ship Energy Efficiency Management Plan (SEEMP) framework, further develop CII metrics and ensure consistency between the IMO’s carbon-intensity and energy-efficiency framework and the IMO Net-Zero Framework.
Defining “Under Way” Operations
The regulatory framework has also become more detailed in distinguishing between periods when a vessel is “under way” and when it is “not under way.” At MEPC 83, amendments to the 2024 SEEMP development guidelines were adopted through resolution MEPC.401(83). The amendments clarify that “under way” refers to the period between full ahead on passage (FAOP) and end of sea passage (EOSP).
The period between EOSP and the vessel’s next FAOP is therefore considered “not under way.”
Following MEPC 84, the IMO Secretariat issued the consolidated amended guidelines through MEPC.1/Circ.925. Paragraph 7.6 further specifies that canal passages, from begin canal passage (EV08) to end canal passage (EV09), should be considered “not under way” because of frequent manoeuvring, acceleration and deceleration.
Separately, MEPC 81 adopted resolution MEPC.385(81), amending appendix IX of MARPOL Annex VI to require ships to collect and report fuel oil consumption while the vessel is “not under way,” categorized by fuel oil type.
Challenges for Conventional Bunker Vessels
IBIA’s latest submission builds on concerns previously raised during the IMO’s review of the CII framework.
At MEPC 81, shipping-industry stakeholders highlighted challenges associated with applying the existing CII requirements across different vessel types. During those discussions, some delegations expressed the expectation that the CII review would lead to a fairer system, while also warning that unresolved issues could result in unintended consequences for the decarbonization process.
The concerns included the potential for ships to be penalized for operational factors beyond their control, including short voyages and extended port waiting times, according to the report of MEPC 81.
MEPC 81 subsequently noted the concerns regarding shortcomings and unintended consequences associated with the CII mechanism and the general agreement that these issues should be considered as part of the CII review process.
IBIA had previously addressed the issue specifically in document MEPC 82/6/9, arguing that bunker vessels are inherently constrained by the operational duties they perform for the wider shipping industry. The association highlighted their predominantly short voyages and in-port manoeuvring.
At that stage, IBIA requested that the CII Guidelines (G5) be amended to introduce a specific correction factor for bunker vessels, similar to correction factors considered for other ship types. The proposal was supported by analyses referenced in documents ISWG-GHG 8/3/1 and MEPC 81/INF.28.
However, as with other proposed correction factors considered during phase 1 of the review, further consideration was deferred to phase 2 of the review at MEPC 83.
IBIA Says Existing Data Can Support a New Approach
According to IBIA, subsequent amendments to the SEEMP guidelines and MARPOL Annex VI have changed the data available for assessing vessel operations. The association points to requirements for recording distance travelled and operating hours separately during “under way” and “not under way” periods, together with fuel oil consumption for the respective operational periods.
IBIA argues that this increased level of data granularity means that it is now possible to calculate CII using distance travelled and fuel oil consumption recorded while a bunker vessel is “under way.” The association says this approach would better reflect the operational role of conventional bunker vessels, whose activities include short voyages and significant periods of in-port manoeuvring.
IBIA’s Proposal to MEPC 85
In paragraph 11 of submission MEPC 85/6/4, IBIA asks the Marine Environment Protection Committee to consider that: “the calculation of CII for a conventional bunker vessel should be when that vessel is ‘under way’ only.”
IBIA has therefore invited the Committee to consider the operational concerns outlined in the submission, together with the changes to IMO data-reporting requirements, and to take action as appropriate. The proposal forms part of the wider IMO review of the CII framework and short-term GHG reduction measures.
MEPC 85/6/4: Submitted by Dr. Edmund Hughes, IBIA Representative to the IMO.
About the International Bunker Industry Association (IBIA)
Established in 1993, IBIA serves as the recognized global voice of the marine energy value chain. Representing a diverse cross-section of fuel suppliers, traders, shipowners, brokers, surveyors, port authorities, and maritime experts spanning more than 70 countries, the association champions transparency, operational quality, and high safety standards. Alongside advocating at the IMO, IBIA continues to guide the maritime sector through both operational challenges and its broader transition toward sustainable, low- and zero-carbon marine fuels.
Source: IBIA