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IMO MEPC 81: negotiations on new GHG reduction requirements continue

The 81st session of the IMO’s Marine Environment Protection Committee (MEPC 81) continued its negotiation of GHG fuel intensity requirements, potentially in combination with a GHG pricing mechanism. Other important decisions include the reporting of transport work and more granular fuel consumption data in the data collection system, and approval of proposals to designate the Canadian Arctic and the Norwegian Sea as NOx, SOx and PM Emission Control Areas.

IMO MEPC 81: negotiations on new GHG reduction requirements continueRelevant for ship owners and managers, equipment manufacturers and fuel suppliers.

Meeting highlights

  • Adopted amendments to the Ballast Water Management Convention, the MARPOL Protocol I, and MARPOL Annex VI
  • Progressed the development of new greenhouse gas (GHG) reduction measures to achieve the ambitions of the GHG Strategy
  • Agreed to develop a working plan for a regulatory framework for on-board carbon capture systems
  • Approved proposals to designate the Canadian Arctic and the Norwegian Sea as Emission Control Areas for nitrogen oxides (NOx), sulphur oxides (SOx) and particulate matter (PM)

Adoption of amendments to mandatory instruments

Amendments to the Ballast Water Management Convention were adopted concerning the use of electronic record books. Electronic ballast water record books will be subject to approval by the flag administration. Additionally, the ship must obtain a declaration confirming that the electronic record book installed on board meets the requirements.

The amendments will enter into force on 1 October 2025.

Amendments to Article V of MARPOL Protocol I were adopted requiring that the loss of freight containers be reported in accordance with the amended SOLAS Regulations 31 and 32 of Chapter V concerning danger messages. The SOLAS amendments are expected to be adopted at MSC 108 in May 2024.

The amendments will enter into force on 1 January 2026, aligned with the expected entry into force date of the SOLAS amendments.

Amendments to MARPOL Annex VI were adopted as follows:

Amendments to Regulation 2 introducing a definition of gas fuel and specifying what information shall be included in the bunker deliver note in case of a low-flashpoint fuel or a gas fuel.

Amendments to Regulation 13.2.2 (NOx) stating that the replacement of a steam system with a marine diesel engine will now be categorized as installing a replacement engine. Consequently, if it is not feasible to install a NOx Tier III certified replacement engine, the flag administration may approve the installation of a Tier II certified replacement engine instead. Correspondingly, the associated guidelines have been revised, and a template has been introduced for flag administrations to report to the IMO when accepting Tier II replacement engines for installation.

Amendments to Regulation 27 enabling the IMO to selectively share data from the data collection system (DCS) with analytical consultancies and research entities on an ad-hoc basis, subject to strict confidentiality rules. Additionally, a company can grant public access to their non-anonymized fuel oil consumption reports.

Amendments to Appendix IX of MARPOL Annex VI, requiring additional data to be submitted through the DCS. This includes data on transport work and detailing fuel oil consumption per consumer type such as main engine(s), auxiliary engine(s), boiler and others, and on whether the ship is underway or not. Additionally, it was agreed to invite for early application of the amendments from 1 January 2025.

The amendments will enter into force on 1 August 2025.

Harmful aquatic organisms in ballast water

Experience-building phase

MEPC 81 concluded a list of provisions and instruments for the review of the Ballast Water Management Convention (BWMC). The topics considered for revision include:

  • development of new guidance and updates to type approval of ballast water management systems
  • additions to the ballast water management plan and the International Ballast Water Management Certificate
  • biological compliance testing for ships at intermediate and renewal surveys
  • including items considered of importance to achieve reliable D-2 compliance into the mandatory sections of the BWMC

The Correspondence Group was re-established and tasked to draft amendments to the BWMC and associated instruments.

Ships operating in challenging water quality

MEPC 81 adopted a resolution concerning interim guidance on the
application of the BWMC to ships operating in challenging waterquality conditions. The guidance includes:

  • steps to identify when a system is inoperable owing to challenging water quality (CWQ); and
  • actions to avoid bypass of the system;
  • steps to recover from bypass, including steps to return to compliance with the D-2 discharge standard; and
  • planning, record-keeping, and communication principles.

The guidance also includes sections intended to guide flag administrations, port states and BWM system manufacturers in providing appropriate support and oversight to ships before, during and after CWQ operations.

Type approval of ballast water management systems (BWMS)

A proposal to include guidance for the type approval process for modifications of already type approved BWMS was discussed. Due to time constraints, the guidance was not completed, and work will continue at the next MEPC.

Temporary storage of treated sewage and/or grey water in the ballast tanks

A circular on guidance for the temporary storage of treated sewage and/or grey water in ballast water tanks was adopted. The proposed amendment to Regulation B-1 regarding the temporary storage of treated sewage and/or grey water was not included at this point but will be considered under the BWMC review.

Air pollution

MEPC 81 discussed the effectiveness of the NOx Tier III standards and the potential extension/revision of the NOx requirements, in particular in ports for low load operation, and invited for proposals for a new work programme output.

MEPC 81 approved a circular providing guidelines for the sampling of fuel oil for determination of compliance with MARPOL Annex VI and SOLAS Chapter II-2.

Revisions of the procedures for exhaust gas cleaning systems (EGCS) regarding the use of nitrate concentration data for EGCS of similar design – as an alternative to the sampling, analysis and quantification requirements – were discussed, but no changes were made at this stage.

MEPC 81 clarified that the Engine Internation Air Pollution Prevention (EIAPP) certificate needs to be re-issued at a change of flag of a ship.

Energy efficiency

Use of ShaPoLi/EPL systems in the EEXI framework

To ensure a consistent and uniform approach to the immediate availability of power, including the power reserve, when using overridable shaft/engine power limitation (ShaPoLi/EPL), MEPC 81 revised the ShaPoLi/EPL guidelines. The revisions are based on provisions set out in IACS Recommendation 172 for systems which do not physically limit shaft or engine power and where the override of shaft power limitation can be indicated by giving an alarm. In this context, manual shaft power limitation systems can inhibit the initiation of the exceedance alarm for up to 5 minutes.

Review of the Carbon Intensity Indicator (CII)

MEPC 81 did not agree on a resolution stating that the CII rating system is currently within an experience building phase and that key elements of the system should be considered interim. Although recognizing that there are shortcomings in the CII framework, it was agreed that the CII is not a provisional measure and that such a resolution would undermine the CII. The concerns raised should be considered as part of the upcoming CII review.

Revision of the Data Collection System (DCS)

MEPC 81 adopted revised guidelines on SEEMP related to reporting fuel oil consumption per consumer type and transport work. This supports the adopted amendments to MARPOL Annex VI mandating the reporting of additional data elements through the DCS.

Carriage of biofuel blends

A proposal to allow for carriage of blends of up to 30% biofuel on bunker barges certified according to MARPOL Annex I was forwarded to the ESPH (Evaluation of Safety and Pollution Hazards of Chemicals) Working Group for further consideration.

Unified Interpretations

MEPC 81 agreed on Unified Interpretations to MARPOL Annex VI

  • the definition of heavy load carriers and
  • the application of the required EEDI to LNG carriers, cruise passenger ships, ro-ro passenger ships, ro-ro cargo ships (vehicle carrier) and ro-ro cargo ships, delivered on or after 1 September 2019.

Reduction of GHG emissions

Mid and long-term measures to reduce GHG emissions

To ensure shipping achieves the ambitions of the 2023 IMO GHG Strategy, the MEPC 80 decided to implement a basket of measures consisting of two parts:

  • A technical element, which will be a goal-based marine fuel standard regulating the phased reduction of marine fuel GHG intensity
  • An economic element, which will be GHG emissions pricing mechanism, linked directly to the GHG intensity mechanism or as a stand-alone mechanism

The measures are scheduled to be adopted in 2025 and enter into force around mid-2027.

At MEPC 81, several regulatory proposals were on the table. While there was no agreement on the package of measures, there was convergence between member states, along with agreement on an overarching structure for the needed regulatory amendments, the “IMO net-zero framework”, in MARPOL Annex VI. This is intended to form the basis for refined proposals, including possible legal language, to be discussed at MEPC 82 in October 2024.

MEPC 81 also agreed to organise the expert workshop on the further development of the basket of mid-term measures, intended to facilitate the understanding of the preliminary findings of the comprehensive impact assessment, which are expected to be available by mid-summer.

Life cycle GHG/carbon intensity for marine fuels

MEPC 81 adopted amendments to the “Guidelines on Life Cycle GHG Intensity of Marine Fuels” (LCA Guidelines), which set out methods for calculating well-to-wake and tank-to-wake GHG emissions for all fuels and other energy carriers (e.g. electricity) used on board a ship. The amendments included the quantification of parameters related to biofuel production, the evaluation of GHG intensity of electricity and the actual tank-to-wake methodologies for actual/onboard emission factors, amongst others.

The LCA Guidelines do not include any provisions for application nor requirements; they are intended to support the GHG Fuel Intensity regulation under development. A GESAMP Working Group was established to consider new default fuel pathway values, certification of actual well-to-tank and tank-to-well emission factors, and more general methodological LCA issues. A Correspondence Group was established to address other social and economic sustainability topics and aspects of marine fuels, for possible later inclusion in the LCA

MEPC 81 considered how to develop a framework for the measurement and verification of tank to-wake emissions of methane (CH4) and nitrous oxide (N2O) in the context of the LCA Guidelines. A separate Correspondence Group was established to further progress the matter.

On-board carbon capture

MEPC 81 discussed the issue of on-board carbon capture and established a Correspondence Group to further discuss the matter and develop a working plan on the development of a regulatory framework for the use of on-board carbon capture systems.

Marine plastic litter

A circular on recommendations for the carriage of plastic pellets by sea in freight containers was approved as the first step in a two-stage approach aimed at reducing the environmental risks associated with the carriage of plastic pellets in packaged form. MEPC 82 in October 2024 will review the action plan to address marine plastic litter from ships.

Identification and protection of Emission Control Areas (ECAs)

MEPC 81 approved proposals to designate the Canadian Arctic and the Norwegian Sea as ECAs for nitrogen oxides (NOx), sulphur oxides (SOx) and particulate matter (PM).

For the Canadian Arctic, assuming adoption at MEPC 82, the requirements take effect as follows:

  • The 0.10% fuel sulphur content requirement takes effect from 1
    March 2027.
  • Tier III NOx requirements will apply to ships constructed on or after 1 January 2025, although the requirements will enter into force at the earliest on 1 March 2026.

For the Norwegian Sea, also assuming adoption at MEPC 82, the requirements take effect as follows:

  • The 0.10% fuel sulphur content requirement takes effect from 1 March 2027.
  • Tier III NOx requirements will apply to ships contracted on or after 1 March 2026; or, in the absence of a contract, keel-laid on or after 1 September 2026; or delivered on or after 1 March 2030.

Provisional list of resolutions and circulars

Please note that the list and document references below are provisional:

Resolution MEPC.383(81)

Amendments to the international convention for the control and management of ship’s ballast water and sediments, 2004 (use of electronic record books)

Resolution MEPC.384(81)

Amendments to Protocol I of MARPOL concerning reporting procedures for the loss of containers

Resolution MEPC.385(81)

Amendments to MARPOL Annex VI concerning low-flashpoint fuels and other fuel oil related issues, marine diesel engine replacing steam system, accessibility of data and inclusion of data on transport work and enhanced granularity in the IMO ship fuel consumption database

Resolution MEPC.386(81)

2024 guidelines as required by Regulation 13.2.2 of MARPOL Annex VI in respect of non-identical replacement engines not required to meet the Tier III limit

Resolution MEPC.387(81)

Interim guidance on the application of the BWM Convention to ships operating in challenging water quality conditions

Resolution MEPC.388(81)

Amendments to the 2022 guidelines for the development of a ship energy efficiency management plan (SEEMP) (Resolution MEPC.346(78))

Resolution MEPC.389(81)

Amendments to the 2022 guidelines for Administration verification of ship fuel oil consumption data and operational carbon intensity (Resolution MEPC.348(78))

Resolution MEPC.390(81)

Amendments to the 2021 guidelines on the shaft/engine power limitation system to comply with the EEXI requirements and use of a power reserve (Resolution MEPC.335(76)), as amended by Resolution MEPC.375(80)

Resolution MEPC.391(81)

2024 guidelines on life cycle GHG intensity of marine fuels (2024 LCA Guidelines)


Guidance for the temporary storage of treated sewage and/or grey water in ballast water tanks


Draft procedure for reporting to the Organization uses of a power reserve


Recommendations for the carriage of plastic pellets by sea in freight containers


Formats for mandatory reports under Article 12 of the Hong Kong Convention


DNV recommends that our customers take into account the work on new GHG reduction ambitions when considering energy efficiency, alternative fuels and other GHG reduction options for their existing fleet and newbuilds, and note the requirements with expected entry into force around mid-2027.

Companies operating in the Canadian Arctic and Norwegian Sea are advised to note the establishment of ECAs and the attendant effective dates of the requirements.

We also recommend signing up for our dedicated MEPC 81 summary webinar, taking place on 3 April 2024.


For more information about decarbonizing shipping and about the relevant DNV services relating to GHG emissions, visit:


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    DATE - Direct Access to Technical Experts via My Services on Veracity.
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    Use our office locator to find the nearest DNV office.

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