This article provides general information, not legal, regulatory or financial advice. Requirements depend on the applicable contract, authority and jurisdiction.
How ships complied
The Energy Efficiency Existing Ship Index applied a design-based efficiency standard to the existing fleet, extending to ships already in service the logic that EEDI applied to newbuildings. Unlike CII, it is a one-time requirement assessed against the ship as designed — not against how it is operated.
Compliance was required by the first annual, intermediate or renewal survey on or after 1 January 2023, with the International Energy Efficiency Certificate reissued accordingly. For most of the world fleet, EEXI is therefore a closed chapter. Its consequences are not.
| Method | What it does | Prevalence |
|---|---|---|
| Engine Power Limitation (EPL) | Mechanically or electronically limits maximum engine power | The dominant solution |
| Shaft Power Limitation (ShaPoLi) | Limits shaft power with monitoring and override | Common on larger tonnage |
| Energy saving devices | Ducts, fins, pre-swirl stators, rotors | Supplementary |
| Propeller optimisation | Re-pitch or replacement | Selective |
| Hull modification | Bulbous bow retrofit | Rare, capital-intensive |
| Alternative fuels | Changes the index calculation | Limited at retrofit stage |
The chart is an indicative distribution, not an audited count — but the shape is not disputed. Power limitation was the pragmatic answer because it is cheap, quick and verifiable, and because most ships were already operating below their design power in a slow-steaming market.
What power limitation actually means in service
Under EPL or ShaPoLi the ship carries an Onboard Management Manual describing the limitation, the monitoring arrangement and — critically — the conditions under which the limitation may be overridden.
| Aspect | Practical consequence |
|---|---|
| Maximum available power reduced | Lower maximum speed |
| Reserve power for heavy weather | Available only through the documented override |
| Override use | Must be recorded, reported and justified |
| Sealing and verification | Class verifies the arrangement; tampering is a serious matter |
| Charterparty speed warranties | Must reflect the limited condition |
The heavy weather override is the point crews and managers must understand precisely. Power limitation is not intended to compromise safety: the manual provides for restoration of power where necessary for the safety of the ship. But it must be used correctly and recorded, and the crew must know how — before the weather arrives, not during it.
The commercial residue
Speed warranties. A vessel with EPL cannot deliver its pre-limitation maximum speed. Charterparty descriptions and performance warranties must be updated, and disputes arise where they were not.
Sale and purchase. The limitation and its documentation form part of the vessel's technical description. Buyers check whether limitation is reversible and at what cost.
Interaction with CII. EEXI is a design measure; CII is operational. Compliance with EEXI does not confer a good CII rating. A ship can hold a valid IEE Certificate and still be rated E, because the two measure different things.
What managers should still be doing
- Verify the documentation is current. Onboard Management Manual, IEE Certificate, technical file, and the class verification record.
- Train the crew on override procedure. Including who authorises, how it is recorded and what is reported.
- Audit override use. Frequent overrides suggest either an inappropriate limitation level or a trading pattern the limitation does not suit.
- Align charterparty descriptions with the limited condition.
- Consider the limitation at retrofit planning. Where energy saving devices are added later, the EEXI calculation may allow a less restrictive limitation.
- Treat it as the floor, not the ceiling. EEXI set a minimum design standard; CII, EU ETS and FuelEU are where the ongoing cost lives.
The wider lesson
EEXI is instructive because it shows how the industry responds to a technical mandate: with the cheapest verifiable solution that satisfies the letter of the requirement. Power limitation delivered compliance without delivering much emissions reduction, because most ships were not using that power anyway.
Regulators drew the same conclusion, which is part of why the emphasis moved to operational measures (CII) and to fuel intensity and pricing (FuelEU, EU ETS, and the IMO Net-Zero Framework). Owners planning for the next decade should assume that design-only compliance strategies will not be sufficient again.
EEXI is established under MARPOL Annex VI; consult IMO guidelines, your class society and flag administration for authoritative requirements. The compliance-method chart is an indicative model. Reviewed by the Zeaclub Editorial Team, 24 August 2026.
Frequently asked questions
Is EEXI a one-time requirement?
Yes. It is assessed once against the ship's design, with the International Energy Efficiency Certificate reissued at the relevant survey. CII, by contrast, is assessed annually on actual operation.
Does engine power limitation reduce safety?
It is not intended to. The arrangements provide for power to be restored where necessary for the safety of the ship, subject to recording and reporting. Crew training on the override procedure is essential.
Can EPL be removed?
Only by achieving compliance another way — for example through energy saving devices or propulsion improvements that change the index calculation, with class verification.
Does passing EEXI mean a good CII rating?
No. They measure different things: EEXI is design efficiency, CII is operational carbon intensity. Many EEXI-compliant ships hold poor CII ratings.