What is EEXI and how does it affect you?

From January 2023, the revised MARPOL Annex VI will enter into force and all existing ships of 400 GT and above must comply with IMO’s Energy Efficiency Existing Ship Index, requirements relating to CO2 emissions per cargo ton and mile.

Datum Electronics Ltd has developed a shaft power limitation (SHaPoLi) Shaft Power System, providing the necessary features and functionality to comply with the MARPOL Annex VI (prevention or air pollution from ships) MEPC.335(76) EEXI regulations.

 Learn about EEXI and how it affects vessel owners.  Datum’s SHaPoLi shaft power acquisition module ensures your vessel complies with IMO’s energy efficiency existing ship index.

Voyage reports are automatically produced in support of the regulatory port authority documentation requirements, providing the most convenient way to evidence EEXI compliance.

In exceptional circumstances where the Ships Master or OICNW need to override the EEXI power limiter (for events such as Adverse Weather, Ice-Infected Waters, Rescue Operations, Avoidance of Pirates and Engine Maintenance), Datums EEXI Shaft Power Acquisition Module logs the exact time and reason for the power exceedance.

How it works

Datums EEXI Shaft Power Acquisition Module continuously monitors, records and displays the instantaneous power being developed at the propulsion shaft when the vessels engine shaft is connected to Datums Shaft Power Meter.


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Ensure compliance with EEXI requirements.

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A standardised and cost-effective solution.

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Non-intrusive and quick retrospective installation.

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Integrate with Existing Datum Shaft Power Meters and Datum Hawk systems.

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Does not limit operational flexibility for vessels with multiple shaft lines or multiple engines per shaft.

Fast solution delivery to assist you in meeting your ESG and socio-economic goals, reducing carbon footprint.


  • What is EEXI?

    The Energy Efficiency eXisting ship Index (EEXI) is a new IMO regulation that aims to reduce CO2 emissions of existing vessels by setting minimum requirements for technical efficiency. EEXI comes into force on 1 January 2023.

  • When will the EEXI enter into force?

    The EEXI was  adopted at MEPC 76 in June 2021 and will enter into force on 1 January 2023.

  • What will be the improvement measures for my vessel?

    Different improvement measures are possible, e.g. Engine power limitation, Shaft power limitation, Engine derating, Propulsion optimization, Energy-saving devices, Please get in contact with DNV’s maritime advisory for a ship-specific evaluation.

  • Do I have a time frame for being compliant? Such as the next annual survey?

    The EEXI Technical File must be approved and the International Energy Efficiency Certificate re-issued by your flag administration or Recognized Organization at the first annual survey after 1 January 2023 at the latest.

  • Which vessels does the EEXI apply to?

    The EEXI must be calculated for all cargo and cruise vessels above 400 GT falling under MARPOL Annex VI. In case of non-conventional propulsion (such as diesel-electric), please see MARPOL Annex VI for further clarification. In case of a major conversion, the EEXI must be recalculated. A required EEXI is applicable for all cargo and cruise vessels above a certain size threshold, depending on the ship type.

  • Will EEXI requirements change in the near future?

    There will be an IMO review of the data in 2026.

  • Can I use any class to approve/verify the EEXI or do I need to use the vessel’s class?

    The approval of the EEXI Technical File and the issuance of the IEEC has to be performed by the respective classification society.

  • What is the required EEXI which my vessels have to fulfil?

    The required EEXI is based on the EEDI reference lines, with the below listed reduction factors applied. This is in most cases equal to the required EEDI in Phase 2 or Phase 3.

  • What documents are to be submitted for class approval?

    You need to submit an EEXI Technical File to your classification society. DNV’s maritime advisory offers support by preparing such documents for you.

  • Will this approval have an impact on statutory certificates?

    Yes, after approval of the EEXI Technical File by the ship’s classification society, the IEE Certificate will be re-issued

  • What is the timeline for the re-issuance of the IEE Certificate?

    The IEE Certificate is re-issued with the first annual survey after 1 January 2023.

  • Is an EPL the only way to improve the EEXI?

    No – Shaft power limitation, Propulsion optimization and Energy-saving can be realised with the installation of Datum Electronics Shaft Power Meter and EEXI Control Panel Interface (Bridge mounted)

  • Are there certain rules or requirements by flag states or class when limiting the engine?

    Classification societies may have certain rules in place for engine limitation (e.g. if Ice class is applicable to your vessel). Please check with your respective classification society individually.

  • What about Ice-classed vessels which have certain requirements regarding minimum speed in ice?

    All requirements regarding the applicable Ice class have to be considered. If it is not possible to fulfil both, Ice class and EEXI requirements, additional measures have to be considered.

  • How about engines which are already derated? Can this engine be limited to an even lower level?

    You could further limit your engine output, for instance for a second time, if necessary to fulfil the requirements by installing Datum Electronics Shaft Power Meter and EEXI Control Panel Interface. Unlike rigid engine limiters, Datum’s EEXI system allows the vessel Master to retain full control of the engine output (for instances where safety is paramount, as defined by SOLAS), whilst still providing the essential data to support the regulatory needs.

  • Would an installation of a diesel-electric engine exempt my vessel from EEXI?

    Yes, except if it is an LNG carrier or cruise passenger ship.

  • What kind of document/proof is required after the EPL has been carried out?

    The following documents should be submitted: EPL Report (by engine manufacturer) Survey statement by class surveyor after EPL installation, EPL Management Plan

  • May EPL lead to other operational issues such as increased vibration?

    Yes. In most cases, limiting the power range goes along with a limitation of the operational revolution range. The new operational revolution rate may cause resonance conditions, resulting in increased structural or machinery vibrations. Higher vibration levels may lead to crew discomfort, structural damages and machinery failure. If power limitation is realized by deactivating cylinders, this will completely change the engine’s dynamics, requiring a new assessment of shaft torsional vibrations and of shipboard vibration due to changed firing frequency, as well as of modified excitation forces and moments. Please contact us again to assess the specific risk for your vessel.

  • What is required to verify the performance improvement of an ESD?

    It is recommended to carry out a model test to predict the performance improvement of the ESD before installation. This model test result will then be used for the calculation of the attained EEXI. The decision about the installation of an ESD should be based on a model test or CFD prediction.

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