EEXI and Engine Power Limitation (EPL)
A technical index calculated only once, but that permanently constrains the maximum available power: the most common route to compliance is limiting the engine, not modifying it.
Operational Explanation
The Energy Efficiency Existing Ship Index (EEXI) is a technical index, calculated only once, that measures the design energy efficiency of an existing ship, conceptually similar to the EEDI required for new construction. In force since 2023, it requires every ship to pass verification against a reference value specific to its type and size.
By far the most common measure for achieving EEXI compliance is Engine Power Limitation (EPL): limiting the maximum available power of the main engine, which directly reduces the calculated index value by lowering the maximum attainable speed and theoretical energy consumption, without requiring invasive technical work on the engine itself.
Regulatory Reference
MARPOL Annex VI, Chapter 4 (Regulation 23): EEXI is verified only once, typically at the first useful periodic survey following entry into force (2023), with issuance of the updated International Energy Efficiency Certificate.
Scope of Application
Existing ships subject to MARPOL Annex VI Chapter 4, according to the applicable size and type thresholds (generally cargo and passenger ships above a minimum tonnage).
Procedure / How to Complete It
- Calculate the ship's EEXI according to the formula applicable to its type and size, comparing it against the required reference value.
- If the calculated EEXI exceeds the required value, assess the available compliance measures: EPL, engine derating, or technical efficiency measures (e.g. energy-saving devices).
- If EPL is chosen, install the approved limitation device (sealable and verifiable), documenting the maximum permitted power.
- Verify that the limiter cannot easily be bypassed or removed without authorization and a new verification.
- Obtain verification and endorsement of the updated International Energy Efficiency (IEE) Certificate from the Classification Society.
Practical Example
Application example: a cargo ship with a calculated EEXI above the required limit, brought into compliance via EPL limiting maximum available power to 82% of the original rated power, with the limitation device sealed and verified by the surveyor.
Real Cases
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Exclusive reliance on EPL without considering the operational impact on maximum available speed | Reduced commercial flexibility of the ship not fully assessed in advance | Assess the operational impact of EPL together with the commercial department before choosing this measure |
| Limitation device not adequately sealed or verifiable | Risk of unauthorized bypass, resulting in silent non-compliance | Always install a certified limitation device that is sealable and verifiable by the surveyor |
| EEXI treated as an isolated obligation, disconnected from the long-term CII strategy | EEXI compliance alone does not guarantee a good CII rating in subsequent years, given the increasing severity of the required reduction factors | Integrate the EEXI/EPL strategy with medium/long-term CII/SEEMP planning |
PSC Observations
Operational Tips
- Always assess the operational impact of EPL with the commercial department before adopting it as a compliance measure.
- Make sure the limitation device is certified, sealable and verifiable, not an improvised solution.
- Do not treat EEXI as an isolated obligation: always link it to the long-term CII strategy.
Checklist
- EEXI calculated according to the applicable formula and compared against the reference value
- Chosen compliance measure (EPL or other) also assessed for operational impact
- Limitation device, if used, certified and sealable
- IEE Certificate updated and verified by the Classification Society
- EEXI strategy integrated with long-term CII/SEEMP planning