MEPC.1/Circ.896

 14 December 2021

 

2021 GUIDANCE ON TREATMENT OF INNOVATIVE ENERGY EFFICIENCY TECHNOLOGIES FOR CALCULATION AND VERIFICATION OF THE ATTAINED EEDI AND EEXI

 

1          The Marine Environment Protection Committee, at its seventy-seventh session (22 to 26 November 2021), approved the 2021 Guidance on treatment of innovative energy efficiency technologies for calculation and verification of the attained EEDI and EEXI, as set out in the annex.

 

2          Member Governments are invited to bring the annexed Guidance to the attention of their Administrations, industry, relevant shipping organizations, shipping companies and other stakeholders concerned.

 

3          The Committee agreed to keep this Guidance under review in light of experience gained in its application.

 

4          This circular supersedes MEPC.1/Circ.815.

 

ANNEX

 

2021 GUIDANCE ON TREATMENT OF INNOVATIVE ENERGY EFFICIENCY TECHNOLOGIES FOR CALCULATION AND VERIFICATION OF THE ATTAINED EEDI AND EEXI

 

TABLE OF CONTENTS

 

1          GENERAL

 

2          DEFINITIONS

 

3          CATEGORIZING OF INNOVATIVE ENERGY EFFICIENCY TECHNOLOGIES

 

4          CALCULATION AND VERIFICATION OF EFFECTS OF INNOVATIVE ENERGY EFFICIENCY TECHNOLOGIES

 

ANNEX 1       Guidance on calculation and verification of effects of Category (B) innovative technologies

 

1          Air lubrication system (Category (B-1))

 

2          Wind assisted propulsion system (Category (B-2))

 

Appendix 1       Method of wind tunnel model test

 

Appendix 2       Global wind probability matrix W_k

 

ANNEX 2       Guidance on calculation and verification of effects of Category (C) innovative technologies

 

1          Waste heat recovery system for generation of electricity (Category (C-1))

 

2          Photovoltaic power generation system (Category (C-2))

 

1          General

 

1.1       The purpose of this guidance is to assist manufacturers, shipbuilders, shipowners, verifiers and other interested parties relating to Energy Efficiency Design Index (EEDI) and Energy Efficiency Existing Ship Index (EEXI) of ships to treat innovative energy efficiency technologies for calculation and verification of the attained EEDI, in accordance with regulations 5, 6, 7, 8, 9 and 20 of Annex VI to MARPOL. Although the term EEDI only is used through the whole guidance, it applies to both the EEDI and the EEXI calculations, as applicable.

 

1.2       There are EEDI Calculation Guidelines and EEDI Survey Guidelines. This guidance does not intend to supersede those guidelines but provides the methodology of calculation, survey and certification of innovative energy efficiency technologies, which are not covered by those guidelines. In the case that there are inconsistencies between this guidance and these guidelines, those guidelines should take precedence.

 

1.3       This guidance might not provide sufficient measures of calculation and verification for ships with diesel-electric propulsion, turbine propulsion and hybrid propulsion systems on the grounds that the attained EEDI Formula shown in EEDI Calculation Guidelines may not be able to apply to such propulsion systems.

 

1.4       The guidance should be reviewed for the inclusion of new innovative technologies not yet covered by the guidance.

 

1.5       The guidance also should be reviewed, after accumulating the experiences of each innovative technology, in order to make it more robust and effective, using the feedback from actual operating data. Therefore, it is advisable that the effect of each innovative technology in actual operating conditions should be monitored and collected for future improvement of this guidance document.

 

2          Definitions

 

2.1       EEDI Calculation Guidelines means 2018 guidelines on the method of calculation of the attained energy efficiency design index (EEDI) for new ships (resolution MEPC.308(73), as amended).

 

2.2       EEDI Survey Guidelines means 2014 guidelines on survey and certification of the energy efficiency design index (EEDI) (resolution MEPC.254(67), as amended by resolution MEPC.261(68) and resolution MEPC.309(73)).

 

2.3       P_p is the propulsion power and is defined as ΣP_ME (In case where shaft motor(s) are installed, ΣP_ME + ΣP_PTI(i),shaft, as shown in paragraph 2.2.5.3 of EEDI Calculation Guidelines).

 

2.4       In addition to the above, definitions of the words in this guidance are the same as those of MARPOL Annex VI, EEDI Calculation Guidelines and EEDI Survey Guidelines.

 

3          Categorizing of Innovative Energy Efficiency Technologies

 

3.1       Innovative energy efficiency technologies are allocated to category (A), (B) and (C), depending on their characteristics and effects to the EEDI formula. Furthermore, innovative energy efficiency technologies of category (B) and (C) are categorized to two sub-categories (category (B-1) and (B-2), and (C-1) and (C-2), respectively).

 

Category (A): Technologies that shift the power curve, which results in the change of combination of P_P and V_ref : e.g. when V_ref is kept constant, P_P will be reduced and when P_P is kept constant, V_ref will be increased.

 

Category (B): Technologies that reduce the propulsion power, P_P, at V_ref, but do not generate electricity. The saved energy is counted as P_eff.

 

Category (B-1): Technologies which can be used at any time during the operation and thus the availability factor (f_eff) should be treated as 1.00.

 

Category (B-2): Technologies which can be used at their full output only under limited condition. The setting of availability factor (f_eff) should be less than 1.00.

 

Category (C): Technologies that generate electricity. The saved energy is counted as P_AEeff.

 

Category (C-1): Technologies which can be used at any time during the operation and thus the availability factor (f_eff) should be treated as 1.00.

 

Category (C-2): Technologies which can be used at their full output only under limited condition. The setting of availability factor (f_eff) should be less than 1.00.

 

 

 

4          Calculation and Verification of effects of Innovative Energy Efficiency Technologies

 

4.1       General

 

4.1.1    The evaluation of the benefit of any innovative technology is to be carried out in conjunction with the hull form and propulsion system with which it is intended to be used. Results of model tests or sea trials of the innovative technology in conjunction with different hull forms or propulsion systems may not be applicable.

 

4.2       Category (A) technology

 

4.2.1    Innovative energy efficiency technologies in category (A) affect P_P and/or V_ref and their effects cannot be measured in isolation. Therefore, these effects should not be calculated nor certified in isolation in this guidance but should be treated as a part of vessel in EEDI Calculation Guidelines and EEDI Survey Guidelines.

 

4.3       Category (B) technology

 

4.3.1    The effects of innovative energy technologies in category (B) are expressed as P_eff which would be multiplied by C_FME and SFC_ME (in the case of P_PTI(i) >0, the average weighted value of (SFC_ME · C_FME) and (SFC_AE · C_FAE)) and f_eff, and then be deducted from the EEDI formula. In the case of category (B-1) technology, f_eff is 1.00.

 

4.3.2    Guidance on calculation and verification of effects of Category (B) innovative technologies is given in annex 1.

 

4.4       Category (C) technology

 

4.4.1    The effects of innovative energy technologies in category (C) are expressed as P_AEeff which would be multiplied by C_FAE, SFC_AE and f_eff, and then be deducted from the EEDI formula. In the case of category (C-1) technology, f_eff is 1.00.

 

4.4.2    Guidance on calculation and verification of effects of Category (C) innovative technologies is given in annex 2.

 

4.5       Average weighted value in the case of P_PTI(i) > 0

 

4.5.1    In the case of P_PTI(i) > 0, both Category (B) and Category (C) technologies might deduct the value of P_PTI(i). In such case, following values are to be used for average weighted value in calculating Σ(f_eff(i) · P_eff(i) · C_F. SFC) in attained EEDI formula:

 

For shaft power(s):

(ΣP_PTI(i),shaft - ·ΣP_{AEeff·ηGEN·ηPTI(i)}) / (ΣP_ME(i) + ΣP_PTI(i),shaft - ·ΣP_{AEeff·ηGEN·ηPTI(i)}),

where, if (ΣP_PTI(i),shaft - ·ΣP_{AEeff·ηGEN·ηPTI(i)}) is taken negative value, the value (ΣP_PTI(i),shaft - ·ΣP_AEeff·η_GEN·η_PTI(i)) should be fixed to zero; and

 

For main engine(s):

ΣP_ME(i) / (ΣP_ME(i) + ΣP_PTI(i),shaft - ·ΣP_{AEeff·ηGEN·ηPTI(i)}),

where, if ΣP_PTI(i),shaft - ·ΣP_{AEeff·ηGEN·ηPTI(i)} is taken negative value, the value (ΣP_PTI(i),shaft - ·ΣP_AEeff·η_GEN·η_PTI(i)) should be fixed to zero.

 

ANNEX 1¹

 

GUIDANCE ON CALCULATION AND VERIFICATION OF EFFECTS OF CATEGORY (B) INNOVATIVE TECHNOLOGIES

_______________

¹     All examples in this chapter are used solely to illustrate the proposed methods of calculation and verification.

 

1          AIR LUBRICATION SYSTEM (CATEGORY (B-1))

 

1.1       Summary of innovative energy efficient technology

 

1.1.1    An air lubrication system is one of the innovative energy efficiency technologies. Ship frictional resistance can be reduced by covering the ship surface with air bubbles, which is injected from the fore part of the ship bottom by using blowers, etc.

 

 

Figure 1 - Schematic illustration of an air lubrication system

 

1.2       Method of calculation

 

1.2.1    Power reduction due to air lubrication system

 

1.2.1.1  Power reduction factor P_eff due to an air lubrication system as an innovative energy efficiency technology is calculated by the following formula. The first and second terms of the right hand side represent the reduction of propulsion power by the air lubrication system and the additional power necessary for running the system, respectively. For this system, f_eff is 1.0 in EEDI formula.

 

                                                                                                (1)

 

*   In the case of P_PTI(i) > 0, the average weighted value of (SFC_ME · C_FME) and (SFC_AE · C_FAE)

 

1.2.1.2  P_eff is the effective power reduction in kW due to the air lubrication system at the 75% t of the rated installed power (MCR). In case that shaft generators are installed, P_eff should be calculated at the 75% MCR having after deducted any installed shaft generators in accordance with paragraph 2.2.5 of EEDI Calculation Guidelines. P_eff should be calculated both in the fully loaded and the sea trial conditions.

 

1.2.1.3  P_PeffAL is the reduction of propulsion power due to the air lubrication system in kW. P_PeffAL should be calculated both in the condition corresponding to the Capacity as defined in EEDI Calculation Guidelines (hereinafter referred to as "fully loaded condition") and the sea trial condition, taking the following items into account:

 

.1       area of ship surface covered with air;

.2       thickness of air layer;

.3       reduction rate of frictional resistance due to the coverage of air layer;

.4       change of propulsion efficiency due to the interaction with air bubbles (self-propulsion factors and propeller open water characteristics); and 

.5       change of resistance due to additional device, if equipped.

1.2.1.4  P_AEeffAL is additional auxiliary power in kW necessary for running the air lubrication system in the fully loaded condition. P_AEeffAL should be calculated as 75% of the rated output of blowers based on the manufacturer's test report. For a system where the calculated value above is significantly different from the output used at normal operation in the fully loaded condition, the P_AEeffAL value may be estimated by an alternative method. In this case, the calculation process should be submitted to a verifier.

 

1.2.2    Points to keep in mind in calculation of attained EEDI with air lubrication system

 

1.2.2.1  V_ref in paragraph 2.2.2 of EEDI Calculation Guidelines should be calculated in the condition that the air lubrication system is OFF to avoid the double count of the effect of this system.

 

1.2.2.2  In accordance with EEDI Calculation Guidelines, the EEDI value for ships for the air lubrication system ON should be calculated in the fully loaded condition.

 

1.3       Method of verification

 

1.3.1    General

 

1.3.1.1  Attained EEDI for a ship with an innovative energy efficient technology should be verified in accordance with EEDI Survey Guidelines. Additional information on the application of air lubrication system, which is not given in the EEDI Survey Guidelines, is contained below.

 

1.3.2    Preliminary verification at the design stage

 

1.3.2.1  In addition to paragraph 4.2.2 of EEDI Survey Guidelines, the EEDI Technical File, which is to be developed by a shipowner or shipbuilder, should include:

 

.1       outline of the air lubrication system;

.2       P_PeffAL : the reduction of propulsion power due to the air lubrication system at the ship speed of V_ref both in the fully loaded and the sea trial conditions;

.3       EDR_full : the reduction rate of propulsion power in the fully loaded condition due to the air lubrication system. EDR_full is calculated by dividing P_MEeffAL by P_ME in EEDI Calculation Guidelines in the fully loaded condition (see figure 2);

.4       EDR_trial : the reduction rate of propulsion power in a sea trial condition due to the air lubrication system. EDR_trial is calculated by dividing P_MEeffAL by P_ME in EEDI Calculation Guidelines in sea trial condition (see figure 2);

 

  

Figure 2 - Calculation of the reduction rate of propulsion power (EDR_full and EDR_trial) due to air lubrication system

 

.5       P_AEeffAL : additional power necessary for running the air lubrication system; and

.6       the calculated value of the EEDI for the air lubrication system ON in the fully loaded condition. 

1.3.2.2  In addition with paragraph 4.2.7 of the EEDI Survey Guidelines, additional information that the verifier may request the shipbuilder to provide directly to it includes:

 

.1       the detailed calculation process of the reduction of propulsion power due to the air lubrication system: P_PeffAL; and

.2       the detailed calculation process of the additional power necessary for running the air lubrication system: P_AEeffAL. 

1.3.3    Final verification of the attained EEDI at sea trial

 

1.3.3.1  Final verification of the EEDI of ships due to the air lubrication system should be conducted at the sea trial. The procedure of final verification should be basically in accordance with paragraph 4.3 of the EEDI Survey Guidelines.

 

1.3.3.2  Prior to the sea trial, the following documents should be submitted to the verifier; a description of the test procedure that includes the measurement methods to be used at the sea trial of the ship with the air lubrication system.

 

1.3.3.3  The verifier should attend the sea trial and confirm the items described in paragraph 4.3.3 of the EEDI Survey Guidelines to be measured at the sea trial for the air lubrication system ON and OFF.

 

1.3.3.4  The main engine output at the sea trial for the air lubrication system ON and OFF should be set so that the range of the developed power curve includes the ship speed of V_ref.

 

1.3.3.5  The following procedure should be conducted based on the power curve developed for air lubrication system OFF.

 

.1       ship speed at 75% MCR of main engine in the fully loaded condition, V_ref, should be calculated. In case that shaft generators are installed, V_ref should be calculated at 75% MCR having after deducted any installed shaft generators in accordance with paragraph 2.2.5 of EEDI Calculation Guidelines; and

.2       in case that V_ref obtained above is different from that estimated at the design stage, the reduction rate of main engine should be recalculated at new V_ref both in the fully loaded and the sea trial conditions. 

1.3.3.6  The shipbuilder should develop power curves for the air lubrication system ON based on the measured ship speed and output of the main engine at the sea trial. The following calculations should be conducted.

 

.1       the actual reduction rate of propulsion power ADR_trial at the ship speed of V_ref at the sea trial; and

.2       if the sea trial is not conducted in the fully loaded condition, the reduction rate of propulsion power in this condition should be calculated by the following formula:

 

Figure 3 - Calculation of the actual reduction rate of propulsion power (ADR_full and ADR_trial) due to air lubrication system

 

1.3.3.7  The reduction of propulsion power due to the air lubrication system P_MEeffAL in the fully loaded and the sea trial conditions should be calculated as follows:

 

P_{PeffAL _ Full} = ADR_Full · P_P                                                                       (3)

 

P_{PeffAL _Trial} = ADR_Trial · P_P                                                                      (4)

 

1.3.3.8  The shipowner or the shipbuilder should revise the EEDI Technical File, as necessary, by taking the result of the sea trial into account. Such revision should include the following contents:

 

.1       V_ref , in case that it is different from that estimated at the design stage;

.2       the reduction of propulsion power P_PeffAL at the ship speed of V_ref in the fully loaded and the sea trial conditions for the air lubrication system ON;

.3       the reduction rate of propulsion power due to air lubrication system (ADR_full and ADR_trial) in the fully loaded and the sea trial conditions; and

.4       the calculated value of the EEDI for the air lubrication system ON in the fully loaded condition. 

 

2          WIND ASSISTED PROPULSION SYSTEM (CATEGORY B-2)

 

2.1       Summary of innovative energy efficient technology

 

2.1.1    Wind assisted propulsion systems (WAPS) belong to innovative mechanical energy efficient technologies which reduce the CO₂ emissions of ships. There are different types of wind propulsion