EEXI

What is EEXI?

The Energy Efficiency Existing Ship Index (EEXI) is an International Maritime Organization (IMO) framework to improve energy efficiency and reduce the fuel consumption of shipping vessels in service.

The EEXI came into effect on January 1, 2023. Existing ships were required to comply by that date and do not need recertification except in case of extensive retrofitting, modifications, or conversion.

Newbuild ships instead must comply with the Energy Efficiency Design Index (EEDI), which uses the same calculation method as the EEXI to report on ship energy efficiency.

To determine a vessel’s energy efficiency, the EEXI considers:

The engine and auxiliary engine power
The transport capacity
The given reference speed

Emissions are calculated for the EEXI using:

The installed power of the main and auxiliary engines
The engine’s specific fuel oil consumption
A conversion factor of the fuel’s mass into CO2 mass

All EEXI calculations must be conducted in accordance with International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI. Calculation requirements for the EEXI are based on those used for the Energy Efficiency Design Index (EEDI).

HOW DO I CALCULATE ATTAINED EXXI?

To comply with the EEXI, ships must assess their energy efficiency index, known as “attained EEXI.” Attained EEXI is then compared with required EEXI, a performance level set by the IMO regulations. Required EEXI values are determined based on fleet statistics per ship type, cargo capacity, and propulsion method.

All ships in service had to individually calculate and receive approval of attained EEXI by their first annual, intermediate or renewal International Air Pollution Prevention (IAPP) survey of 2023. Today, re-calculating EEXI is only necessary in case of extensive retrofitting, modifications, or conversion. Instead of the EEXI, newbuild ships must calculate their compliance with the Energy Efficiency Design Index (EEDI).

How do I achieve EEXI compliance?

After January 1, 2023, vessels in service attained EEXI and related technical files were verified on a one-time basis during their annual, intermediate or renewal International Air Pollution Prevention (IAPP) survey. Today, achieving EEXI compliance is only necessary in case of extensive retrofitting, modifications, or conversion. Instead of the EEXI, newbuild ships must comply with the Energy Efficiency Design Index (EEDI).

EEXI-compliant ships are issued an International Energy Efficiency Certificate (IEEC). Non-compliant ships must find ways to comply with the required EEXI values. Technical changes such as Engine Power Limitation (EPL) and Shaft Power Limitation (SHaPoLi) can reduce the calculated emissions. Ships with particularly poor EEXI performance require retrofitting, energy-saving devices, propeller modifications or green solutions like wind-assisted propulsion.

Sebastien

Crouzet

International Statutory Affairs Manager

Bureau Veritas M&O

"Few things set shipowners on edge quite like the phrase ‘required calculations’. When the EEXI was announced, Bureau Veritas immediately started developing a digital calculation tool. Designed with users in mind, VeriSTAR Green does the heavy lifting, helping shipowners report on emissions, calculate EEXI and achieve regulatory compliance."

Bureau Veritas’ EEXI services

Bureau Veritas Marine & Offshore supports shipowners, operators and managers in performing EEXI assessments and gain approval for their preliminary technical files. We help shipowners identify the technical measures needed to improve their vessels’ energy efficiency and limit emissions. Our experts ensure that ships meeting EEXI requirements receive the requisite IEEC.

Get the help you need from our experts

Our services are complemented by VeriSTAR Green, a web platform designed to make following EEXI regulations easier. This platform helps users easily and efficiently perform EEXI calculations. Shipowners can calculate both attained and required EEXI values, comparing the two and measuring their fleets’ environmental impact. VeriSTAR Green also gives users digital access to Bureau Veritas experts who can verify their emissions calculations. They can also reach technical advisory services to improve performance from independent experts from BV Solutions M&O.

EEXI FAQs

What is the difference between EEXI and EEDI?

The Energy Efficiency Design Index (EEDI) is a design index applicable to newbuilds, while the Energy Efficiency Existing Ship Index (EEXI) applies to existing vessels. Both the EEDI and EEXI use the same calculation method to report on ship energy efficiency. Approximately 70% of EEDI-compliant ships are expected to achieve EEXI compliance without alteration.

To Which ships does EEXI apply?

Energy Efficiency Existing Ship Index (EEXI) provisions apply to all ships over 400 Gigatonnes that are categorized in the International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI regulations listed below and subject to MARPOL Annex VI chapter 4. As required EEXI values are determined by ship type, operators will need to assess ship energy efficiency against vessel type requirements.

MARPOL Annex VI regulation	Ship type
2.2.5	Bulk carrier
2.2.7	Combination carrier
2.2.9	Containership
2.2.11	Cruise passenger ship
2.2.14	Gas carrier
2.2.15	General cargo ship
2.2.16	LNG carrier
2.2.22	Refrigerated cargo carrier
2.2.26	Ro-ro cargo ship
2.2.27	Ro-ro cargo ship (vehicle carrier)
2.2.28	Ro-ro passenger ship
2.2.29	Tanker

What is VREF in EEXI?

A required element in calculating Energy Efficiency Existing Ship Index (EEXI) is a vessel’s reference speed (VREF) at a certain draft. EEXI calculation guidelines enable shipowners to determine VREF using an approximate formula for their ship type and installed power. Shipowners can also use more precise methods, such as sea trials, towing tank tests or computational fluid dynamics assessments.
Is EEXI evaluated annually?

Existing ships are only required to gain Energy Efficiency Existing Ship Index (EEXI) approval once over the course of their in-service lifetime. Only in the case of extensive retrofitting, modifications, or conversion will EEXI need to be reevaluated and reapproved.
How can I improve my vessel to achieve EEXI compliance?

Shipowners can turn to Engine Power Limitation (EPL) or Shaft Power Limitation (SHaPoLi) as short-term solutions for reducing emissions. Owners can also make permanent modifications to engines, such as cutting out turbo chargers, or installing energy-saving devices like wake-equalizing ducts, bulbous bows or propeller fins.
Is EEXI compliance going to be expensive?

The majority of vessels will face limited capital expenditures (CAPEX) to meet Energy Efficiency Existing Ship Index (EEXI) requirements, as most ships will not undergo modification. EEXI may affect operational expenditures (OPEX) for some vessels, as the crew undertakes additional training and the ship makes speed adjustments. However, for ships undergoing retrofitting to achieve compliance, CAPEX may be significant. Shipowners will evaluate and decide the most cost-effective options on a case-by-case basis.