The required EEXI reduction factor table and when an EEDI value can stand in (MARPOL Annex VI Regulation 25)

EEXI is an index that comes from a ship’s design and specification, not from operating results. So it is not a value refreshed each year the way CII is; it is calculated once and verified. The practical questions are when that once is, what the verification rests on, and whether an existing EEDI value can be used.

Ships that have undergone a major conversion are inside the scope

Regulation 23 has the attained EEXI calculated for each ship and for each ship which has undergone a major conversion, within the ship type categories the Annex lists.

That major conversion is written as its own item shows what kind of index this is. It is not a value settled once and for all; where the ship’s specification changes, it is calculated again.

Verification rests on the technical file

The attained EEXI shall be specific to each ship and shall indicate the estimated performance of the ship in terms of energy efficiency, and be accompanied by the EEXI technical file which contains the information necessary for the calculation of the attained EEXI and which shows the process of the calculation. The attained EEXI shall be verified, based on the EEXI technical file, either by the Administration or by any organization duly authorized by it.

Two things have to be in the technical file: the information necessary for the calculation, and the process of the calculation. A document carrying only the result does not meet the requirement.

The verifier is the Administration or an organization duly authorized by it, and what the verification rests on is that technical file.

There are conditions for using an EEDI value as the EEXI

3 Notwithstanding paragraph 1 of this regulation, for each ship to which regulation 22 of this Annex applies, the attained EEDI verified by the Administration or by any organization duly authorized by it in accordance with regulation 22.1 of this Annex may be taken as the attained EEXI if the value of the attained EEDI is equal to or less than that of the required EEXI as required by regulation 25 of this Annex. In this case, the attained EEXI shall be verified based on the EEDI technical file.

Two conditions. The ship is one to which regulation 22 applies, and the verified attained EEDI is equal to or less than the required EEXI. Where both hold, that EEDI value may be taken as the attained EEXI, and the verification then rests on the EEDI technical file.

The required EEXI applies a reduction factor to the reference line value

The required EEXI is the EEDI reference line value with a reduction factor applied, and the attained EEXI has to be at or below it. The reduction factor is given as a percentage and set by Table 3 by ship type and size band. The EEDI reference line value itself is calculated as regulation 24 provides.

Ship type	Size	Reduction factor
Bulk carrier	200,000 DWT and above	15
Bulk carrier	20,000 and above but less than 200,000 DWT	20
Bulk carrier	10,000 and above but less than 20,000 DWT	0-20
Gas carrier	15,000 DWT and above	30
Gas carrier	10,000 and above but less than 15,000 DWT	20
Gas carrier	2,000 and above but less than 10,000 DWT	0-20
Tanker	200,000 DWT and above	15
Tanker	20,000 and above but less than 200,000 DWT	20
Tanker	4,000 and above but less than 20,000 DWT	0-20
Containership	200,000 DWT and above	50
Containership	120,000 and above but less than 200,000 DWT	45
Containership	80,000 and above but less than 120,000 DWT	35
Containership	40,000 and above but less than 80,000 DWT	30
Containership	15,000 and above but less than 40,000 DWT	20
Containership	10,000 and above but less than 15,000 DWT	0-20
General cargo ship	15,000 DWT and above	30
General cargo ship	3,000 and above but less than 15,000 DWT	0-30
Refrigerated cargo carrier	5,000 DWT and above	15
Refrigerated cargo carrier	3,000 and above but less than 5,000 DWT	0-15
Combination carrier	20,000 DWT and above	20
Combination carrier	4,000 and above but less than 20,000 DWT	0-20
LNG carrier	10,000 DWT and above	30
Ro-ro cargo ship (vehicle carrier)	10,000 DWT and above	15
Ro-ro cargo ship	2,000 DWT and above	5
Ro-ro cargo ship	1,000 and above but less than 2,000 DWT	0-5
Ro-ro passenger ship	1,000 DWT and above	5
Ro-ro passenger ship	250 and above but less than 1,000 DWT	0-5
Cruise passenger ship having non-conventional propulsion	85,000 GT and above	30
Cruise passenger ship having non-conventional propulsion	25,000 and above but less than 85,000 GT	0-30

Values shown as a range are interpolated

• 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.

A cell carrying two values joined is a range, not a factor in itself. The factor is interpolated linearly between them according to ship size, with the lower value applied to the smaller ship. So two ships of the same type in the same band come out with different factors when their DWT differs.

That the size basis for cruise passenger ships differs from the rest is also there to read in the table. The other types are in deadweight tonnage; this one is in gross tonnage.

This regulation carries a review date as well

Regulation 25 paragraph 3 has the Organization complete a review by 1 January 2026 assessing the effectiveness of the regulation. That is the same date as the CII review in regulation 28. The design-side index and the operation-side index come up for review in the same year.

Worth confirming

The passages above come from pages 35 and 40 of the 2021 revised MARPOL Annex VI (MEPC.328(76)). The table above reproduces Table 3; the EEDI reference line value and the interpolated result have to be calculated from that ship’s particulars. Which row of the table the ship falls in, whether it has undergone a major conversion, and whether the technical file shows the calculation process are where the actual judgement starts.