EEXI – Energy Efficiency Existing Ship Index

The most common method is assumed to be Engine Power Limitation (EPL) by re-setting the fuel index by limiting the fuel rack using either mechanical stop or setting the control system in combination with an approved override functionality as defined in the IMO guidelines (EPL). Permanent modifications of engines, for example by permanent cut-out of one turbo charger, is another alternative; switchable blinds are not considered to be accepted as a permanent means in this context. Another method could be to install energy saving devices like rotating sails, bulbous bow or propeller fins. Please get in touch with DNV Maritime Advisory services for a ship-specific evaluation.

Yes, engines could be limited a second time, if necessary to fulfil the requirements.

For permanent power limitations notations it must be evaluated if the notation complies with the new power settings. If EPL with approved override functionality is applied, notations are not affected.

No, the EPL only has to be activated by the first periodical survey in 2023 at the latest.

Yes, the manouvering charts/posters need to be updated to reflect the manouvering capabilities of the vessel with the power limitations installed. Vessels with overridable power limitation therefore need to be provided with two sets of manouvering charts/-posters in the wheelhouse: one covering the vessel capabilities in un-limiting mode and one covering the vessel capabilities in limiting mode.

Power limitations done by limiting the engine fuel index and limiting shaft power by the installation of a shaft torque meter in combination with an approved override functionality are considered non-permanent within the context of the EEXI, meaning P_ME=83% MCR_Lim. In order to consider a power limitation as permanent within the context of the EEXI, the power limitation needs to involve design modifications such as engine modifications or propeller retrofits. This will give P_ME=75% MCR_Derated. Engine power limitations by fuel index limitation only, without an approved override functionality, are also considered permanent and must be tamper-free.

There is no mandatory requirement to retrofit a new control system from the bridge. If applicable, this needs to be covered in the OMM.

Indeed, for determining the reference speed in the EEXI calculation, the IMO has agreed that numerical calculations can be applied to replace model tests. It is also possible to use original model tests or sea trials and to evaluate improvements by propeller retrofit or ESD installation by CFD calculation.

The numerical calculations are to be performed according to quality and the technical standards ITTC 7.5-03-01-04 (as stated in the industry guideline for EEDI calculation and verification) and must be well documented in a submitted report.

The principles to be considered are:

• Standardized and evaluated solution algorithm
• Turbulence modelling, meaning consideration of the ship in self propulsion condition with free sinkage and trim
• Consistent mesh generation with standardized resolution in relevant areas (propeller/hull/wake)