ENERGY EFFICIENCY DESIGN INDEX FOR EXISTING SHIPS (EEXI)

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11 months ago

Under the Greenhouse Gas Strategy towards 2050, IMO has set new goals in MEPC 80 to reduce
carbon intensity by

20% reduction in emission by 2030 (compared to 2008 level).
70% reduction in emission by 2040 (compared to 2008 level) and
Net Zero emission by 2050.

Different measures were considered and widely discussed, and IMO has decided to introduce a
combination of technical and operational measures.

Whereas the EEXI is the technical measure, just looking at the design of the ship in comparable
way as the EEDI does for new buildings.
SEEMP Update and CII rating are the operational measures to reduce the GHG (Green House
Gases).

During MEPC 76 in June 2021, IMO adopted amendments to MARPOL Annex VI, introducing an
Energy Efficiency Design Index for existing ships (EEXI).

EEXI (Energy Efficiency Existing Ship Index) regulations has started from 1st January 2023 after the
amendments to MARPOL ANNEX VI entered into force on 1st November 2022. The EEXI
regulations will apply to existing vessels as a short-term measure to reduce GHG emissions. The
application of EEXI regulations differs depending on the ship, so please read the following
instructions carefully and take all necessary measures.

Ships to which the regulation applies will be required to calculate the EEXI value of each individual
ship (i.e. attained EEXI) and the value shall be equal to or less than the allowable maximum value
(i.e. required EEXI). Furthermore, if attained EEXI cannot meet the required EEXI, the ship should
implement countermeasures, such as Engine Power Limitation (EPL), Shaft Power Limitation
(SHaPoLi), retrofitting energy saving devices (ESD), etc.

The EEXI regulation evaluates the energy efficiency of existing ships as described above. EEXI is
expressed in units [g/ton-mile] and refers to the calculated CO2 emissions (g) from the transport of 1
ton of cargo for 1 nautical mile.

The EEXI limit value (called required EEXI) differ depending on ship type and size, and if the EEXI
calculated for an individual ship (called Attained EEXI) exceeds the required EEXI, improvement
measures must be taken to lower the EEXI value.

Applicability:

The EEXI regulations apply to all vessels of 400GT and above, falling under the ship type categories
subject to compliance with EEDI regulations.

EEXI does not apply to:

Category A ships (ships designed for operation in polar waters in at least medium first-year ice)
as defined in the Polar Code, and
Ships having non-conventional propulsion except for cruise ships (non-conventional propulsion)
and LNG carriers (conventional and non- conventional propulsion).

Timeline of EEXI:
Enforcement of EEXI regulations has begun from January 1, 2023.
The EEXI verification shall take place at the following timing:

Ships delivered before 1 January 2023	First annual, intermediate or renewal survey of the International Air Pollution Certificate (IAPP Certificate), whichever is the first, on or after 1 January 2023
Ships delivered on or after 1 January 2023	Initial survey of the International Energy Efficiency Certificate (IEE Certificate)

ATTAINED EEXI – REGULATION 20A

The attained EEXI will be ship-specific i.e., it will be calculated for each individual vessel and verified
by the Flag Administration or any organization authorized by it (e.g. Classification Societies). These
calculations will be included in each vessel’s EEXI technical file along with any supporting technical
data and information used in the calculation process.

For all vessels that have been verified for EEDI and issued an International Energy Efficiency
Certificate (IEEC), the attained EEDI will be equal to the attained EEXI, provided that the attained
EEDI meets the regulatory limits established by the newly introduced required EEXI regulation 21A.

When a ship’s Attained EEDI does not meet the Required EEXI, the following technical modification options may be considered for compliance

Engine Power Limitation (EPL) or Shaft Power Limitation (SHaPoLi)
Retrofit of Energy Saving Devices (ESD),
Use of alternative fuels, like, Methanol, LNG, etc.

For such cases, the Attained EEXI calculation shall be calculated and verified based on the guidelines adopted by the IMO RESOLUTION MEPC.308(73) and MEPC 333(76).

REQUIRED EEXI – REGULATION 21A
Regulation 21A provides the requirement and guidelines for calculating the required EEXI and verifying that a vessel’s attained EEXI is lower than the required EEXI.

The Required EEXI would be the regulatory limit for EEXI and its calculation will be in line with the EEDI reference line values using reduction factors specific to EEXI, as shown in below table.

Reduction factors (in Percentage) for the EEXI relative to the EEDI reference line

(*) reduction factor to be linearly interpolated between the two values dependent upon ship size. The
lower value of the reduction factor is to be applied to the smaller ship size.

EEXI SURVEY AND CERTIFICATION

For the verification of a vessel’s attained EEXI, an application for a survey would be submitted
to the verifier together with an EEXI Technical File containing the necessary information for the
verification and supporting background documents.
Upon final verification, each vessel’s attained EEXI and required EEXI values will be indicated
on the vessel’s IEEC issued by the Flag Administration.

For cases where the attained EEDI of the ship satisfies the required EEXI, a confirmation of compliance with EEXI regulations and subsequent update of the IEEC would be sufficient.

Engine Power Limitation (EPL) based on EEXI regulations

Engine Power Limitation (EPL) is a system to improve a ship’s energy efficiency by limiting the ship’s
engine power and is the simplest and most practical measure.

Type of EPL method: EPL is generally divided into the following 3 methods, and adoption of the
method -1 or 2 is strongly recommended for safety.

S.no	Methods	Applicable type of Engine	Outline of methods
1	Engine Power Limitation Method	a) Electronically controlled engines b) Electronical governor control engines	The engine remote control system calculates the actual power of the engine and controls the power under MCR .
2	Fuel Index Limitation Method	a) Electronically controlled engines b) Electronical governor control engines c) Mechanical governor control engines	Limiter value of Fuel Index is set on the engine remote control system based on MCR , and the power is controlled under MCR .
3	Mechanical Stopper Method	a) Electronical governor control engines b) Mechanical governor control engines	Limiter is set in the mechanical governor based on the MCR and the power is limited in the MCR.

If power restriction by the EPL affects the actual service (i.e. service speed cannot be maintained due to the power limitation), the improvement will be made by a method other than the EPL. In this case, individual measures will be required for individual ships (for example, improvement of fuel consumption rate of main engine by installation of energy-saving equipment).

Shaft Power Limitation (SHaPoLi) based on EEXI regulations

Shaft Power Limitation (SHaPoLi) is a method which limits vessel’s fuel consumption by restricting the output power of propeller shaft(s). A shaft torque and speed measurement system are used to provide a real-time, high accuracy input values based on which shaft power is regulated.

EPL / SHaPoLi Override function switch for emergency case:
The EPL / SHaPoLi, which remains in place at all times during normal operation, can be manually overridden to allow for situations where a power reserve above the normal limit is required for the purpose of safely securing the ship. Any such override must be immediately recorded in OMM and
informed to the relevant classification societies. Few type of installation (in Electronic controlled engines) includes automatic logging to fulfil this obligation.

General requirement for EPL / SHaPoLi system.

The SHaPoLi / EPL system (or each subsystem) should be tamper-proof.
The system should be non-permanent and should be over-ridable by ship’s master or Officer InCharge of Navigation Watch (OICNW) to enable the use of power reverse (Power reserve means shaft / engine power above the limited power which cannot be used in normal operation unless in the case when SHaPoLi / EPL is unlimited for the purpose of securing the ship safety).
For systems that use a password / PIN to control access to the power reserve override, the necessary password / PIN should always be available when override is required.
The control unit of the SHaPoLi / EPL system on electronically controlled engines must convey information clearly and conspicuously under two specific circumstances:

Exceeding Power Limits: It should inform when the ship’s shaft or engine power surpasses
the specified limits as detailed in the Onboard Management Manual (OMM) for SHaPoLi /
EPL.
System Malfunction: It should also provide notification in the event of any malfunction within
the system.

For EPL for the mechanically controlled engine, the sealing device must meet one of the following requirements:

Visibly indicate removal of the sealing when the ship’s engine power exceeds the limited engine power or in the event of system malfunction or
Be equipped with other systems like an alert-monitoring system which can indicate when the ship’s engine power exceeds the limited engine power or in case of system malfunction.

The SHaPoLi / EPL system designed for electronically controlled engines is required to display the following operational data:

In the case of SHaPoLi, it should continuously record shaft rotational speed, shaft torque, and shaft power. In instances involving multiple shaft configurations, the total shaft power should also be consistently recorded in unrestricted mode.
For EPL, it must feature a fuel index sealing system or a power limitation system that can effectively indicate and record instances when the unlimited mode is being utilized.

Technical requirements for SHaPoLi / EPL system.

The EPL / SHaPoLi system should consist of the following main arrangements:

SHaPoLi:

Sensors for measuring the torque and rotational speed delivered to the propeller(s) of the
ship. The system includes the amplifier and the analogue to the digital converter.
A data recording and processing device for tracking and calculation of the data.
A control unit for calculation and limitation of the power transmitted by the shaft to the
propeller(s).

EPL (For the mechanically controlled engine):

A sealing device which can physically lock the fuel index by using a mechanical stop screw
sealed by wire or
An equivalent device with governor limit setting so that the ship’s crew cannot release the
EPL without permission from the ship’s master or OICNW, as shown in below figure.

EPL (For electronically controlled engine):

It should have fuel index limiter which can electronically lock the fuel index or
Direct limitation of the power in the engine’s control system so that the ship’s crew cannot
release the EPL without permission from the ship’s master or OICNW.

Where technically achievable and practical, the SHaPoLi / EPL system should be operable from the ship’s bridge, eliminating the need for ship’s personnel to be present in the machinery space.

Use of a power reserve by un-limiting the SHaPoLi / EPL

The use of a power reserve is allowed only for following conditions:
a) For the purpose of securing the safety of a ship.
b) Saving life at sea during operation in adverse weather condition and Ice-infested waters.
c) Participation in search and rescue operations.
d) Avoidance of pirates and
e) Engine maintenance.

Any use of power reserve should be recorded in OMM by chief engineer and countersigned by
master. The record should include the following:

a) Ship type
b) IMO number
c) Ship size in DWT and/or GT, as applicable
d) Ship’s limited shaft / engine power and ship’s maximum unlimited shaft / engine power.
e) Position of the ship and timestamp when the power reserve was used.
f) Reason for using the power reserve.
g) Beaufort number and wave height or ice condition in case of using the power reserve under adverse weather condition.
h) Supporting evidence (e.g. expected weather condition) in case of using the power reserve for avoidance action.
i) Records from the SHaPoLi / EPL system for the electronically controlled engine during the power reserve was used; and .
j) Position of the ship and timestamp when the power limit was reactivated or replaced.

When an EPL / SHaPoLi override is activated but the power reserve remains unused, this occurrence should be documented in both the bridge and engine-room logbooks. The engineroom logbook
should specifically note the power usage during the period when the override was activated.

EPL / SHaPoLi system should be reset as soon as possible, with all pertinent reset details being recorded in OMM and both bridge & engine-room logbooks. If it is determined (by third party inspectors like PSC, FSI etc.) that such overriding situations are not properly reported or documented, then the reactivation of SHaPoLi / EPL should have to be immediately conducted in the presence of the Administration or the RO at the port.

When an EPL/SHaPoLi override is activated and power reserve has been utilized, the ship must promptly inform its Administration or Recognized Organization (RO) responsible for certificate issuance, along with the competent authority at the intended destination port.

Once the risk is mitigated, EPL / SHaPoLi system must be reactivated at the earliest. The confirmation of reactivation should be supported with evidence like engine power log (print out or photo), photo of mechanical sealing with date and time etc. and such evidence must be filed in the OMM. These evidence are subject to verification by administration at the earliest opportunity.

Any defect of the SHaPoLi / EPL system should be reported to the Administration or RO responsible for issuing the relevant certificate.

Onboard Management Manual (OMM) for SHaPoLi / EPL

The SHaPoLi / EPL system should be accompanied by the OMM for SHaPoLi / EPL that should be permanently on board the ship for inspection.
The OMM for SHaPoLi / EPL should be verified by the Administration or the RO after a survey verifying the ship’s attained EEXI.
OMM for SHaPoLi should include the following, as a minimum:

A technical description of the main system and auxiliary system.

Identification of key components of the system by manufacturer, model/type, serial number and other details as necessary.
Description of a verification procedure demonstrating that the system is in compliance with the technical description.
The maximum shaft power for which the unit is designed.
Service, maintenance and calibration requirements of sensors according to sensor manufacturer and a description how to monitor the appropriateness of the calibration intervals, if applicable.
The SHaPoLi record book for the recording of service, maintenance, and calibration of the system.
The description how the shaft power can be limited and unlimited and how this is displayed by the control unit.
The description of how the controller limits the power delivered to the propeller shaft.
The identification of responsibilities.
Procedures for notification of the use of power reserve and the detections of malfunctions of the system.
Time required for un-limiting / overriding the SHaPoLi and
Procedures for survey of the SHaPoLi system by the Administration/RO.

OMM for EPL should include the following, as a minimum:

Rated installed power (MCR) or motor output (MPP) and engine speed (NMCR).
Limited installed power (MCRlim) or motor output (MPPlim) and engine speed (NMCR,lim).
Technical description of the EPL system.
Method for sealing the EPL (mechanically controlled engine).
Method for locking and monitoring the EPL (electronically controlled engine).
Procedures and methods for releasing the EPL.
Time required for unlimiting the EPL.
Procedures for survey of the EPL system by the Administration/RO.
Procedure for the report on release of the EPL.
Administrator or person-in-charge of the EPL system.