What is EEXI? Energy Efficiency Existing Ship Index

EEXI in one paragraph

The Energy Efficiency Existing Ship Index extends the new-build EEDI logic backwards across the in-service fleet. The IMO adopted it on 17 June 2021 as part of the revised MARPOL Annex VI in Resolution MEPC.328(76), and it took effect on 1 November 2022. Every cargo and passenger ship of 400 GT and above on international voyages has to demonstrate an attained EEXI at or below a required EEXI value at its first periodical, intermediate, or renewal IAPP survey on or after 1 January 2023. Pass it once and the design check is closed for the life of the ship, unless a major conversion changes the inputs. That single-survey character is the thing that most separates EEXI from the Carbon Intensity Indicator, which has to be earned again every calendar year.

EEXI is a technical, design-based metric measured in grams of CO2 per tonne-nautical mile. It does not measure what a ship actually burns. It estimates the CO2 a ship would emit per unit of transport work at a defined reference condition, using engine power, specific fuel consumption, the carbon factor of the fuel, the ship’s capacity, & a reference speed. Because the formula rewards a slower reference speed, the cheapest path to compliance for most owners is to cap installed power so the reference speed drops. The legal hook for that cap, the override mechanism, and the onboard paperwork all sit in Resolution MEPC.335(76). You can sanity-check the numbers with our EEXI Attained calculator and the EPL calculator before a class society ever sees the file.

Legal basis and scope

EEXI lives in Chapter 4 of the revised MARPOL Annex VI. Regulation 23 sets out the attained EEXI obligation; Regulation 25 sets the required EEXI and the ship-type reduction factors. The instrument is Resolution MEPC.328(76), the 2021 revised Annex VI, which the Marine Environment Protection Committee adopted at its 76th session in June 2021. It entered into force on 1 November 2022 under the tacit-acceptance procedure, & the compliance deadline for individual ships is the first annual, intermediate, or renewal survey of the International Air Pollution Prevention (IAPP) Certificate on or after 1 January 2023.

The scope is wide but not universal. EEXI applies to ships of 400 GT and above that fall under Annex VI and are engaged on international voyages. Both the attained-value calculation and the required-value target are defined by ship type: bulk carrier, gas carrier, tanker, container ship, general cargo, refrigerated cargo carrier, combination carrier, LNG carrier, ro-ro cargo (vehicle carrier), ro-ro cargo, ro-ro passenger, cruise passenger with non-conventional propulsion. A ship that doesn’t fit one of those defined types, or that uses propulsion the EEDI baseline never modeled, can fall outside the numerical EEXI requirement even while remaining inside Annex VI for everything else, such as the SEEMP and CII obligations.

Diesel-electric, turbine, & hybrid propulsion ships were brought into the framework with specific calculation provisions rather than left out, because the original EEDI reference lines were built around mechanically driven ships with conventional two-stroke or four-stroke main engines. The calculation guideline handles those cases explicitly. Ships that pre-date the EEDI era still owe an EEXI; the index reaches vessels delivered long before 2013, which is the whole point of an existing-ship measure.

A useful way to hold the three Annex VI efficiency instruments apart: EEDI is the design gate every new ship passes at delivery; EEXI is the one-time design gate the existing fleet passed in 2023; CII is the operational scorecard the trading fleet earns every year. EEDI and EEXI use the same arithmetic family. CII uses an entirely different one based on reported fuel and distance.

Diesel-electric, turbine, and dual-fuel cases

The original EEDI reference lines assumed a mechanically driven ship: a two-stroke or four-stroke main engine turning a fixed-pitch propeller through a shaft. Diesel-electric ships, where prime movers generate electricity that drives propulsion motors, don’t map onto that arrangement directly, so the calculation guideline in Resolution MEPC.333(76) sets out how to define the equivalent main-engine power and specific fuel consumption for them. Steam and gas turbine propulsion, common on older LNG carriers and a few cruise ships, gets the same treatment, with the turbine fuel rate standing in for the diesel specific fuel consumption. Dual-fuel engines are handled by computing the attained value for the fuel the ship is certified to use for compliance, with the carbon factor of that fuel; an LNG-burning dual-fuel ship books the 2.750 factor for the gas mode it intends to run. These provisions are why pre-EEDI ships of every propulsion type still owe a defined attained EEXI rather than being left outside the numbers.

The attained EEXI calculation

The attained EEXI is the number you compute for the specific ship. It re-uses the EEDI numerator and denominator, with one decisive change in the reference condition. The numerator is the CO2 mass rate at the reference load: main-engine power times its carbon factor times its specific fuel consumption, plus the auxiliary-engine contribution, with credits subtracted for innovative energy-efficiency technology and for any shaft motor. The denominator is the transport work: deadweight capacity times the reference speed.

The reference power points are fixed by the calculation guideline in Resolution MEPC.333(76). Main-engine power is taken at 83% of the maximum continuous rating, or 83% of the limited MCR where the engine has been derated through an Engine Power Limitation. Auxiliary power is estimated from a formula tied to total propulsion power. The reference speed $V_{ref}$ is the speed the ship makes, in deep water under the reference loading condition, at 75% of that same MCR figure. That is the lever. Because the resistance a hull pushes through rises with roughly the square of speed and the power to drive it rises with roughly the cube, a small reduction in available MCR drops $V_{ref}$ enough to move the whole ratio.

The carbon factor $C_F$ converts fuel mass to CO2 mass. For heavy fuel oil it is 3.114 tonnes of CO2 per tonne of fuel; for marine diesel and gas oil it is 3.206; for LNG it is 2.750. Switching the assumed fuel changes $C_F$ and therefore the attained value directly, which is why an LNG-capable ship books a structurally lower EEXI from the same hull and engine. The specific fuel consumption is the test-bed value at the relevant load, corrected per ISO conditions and taken from the engine’s NOx Technical File where one exists.

The result is an estimate, not a measurement. It assumes calm-water performance at a single loading point and a single fuel. It says nothing about how the ship is actually operated, the routes it runs, the weather it meets, or the cargo it lifts. That distinction is the heart of the EEXI versus CII question that comes up in nearly every owner conversation.

Capacity and the denominator

Capacity in the denominator is not the same number for every ship type, and getting it wrong is one of the more common file errors. For most cargo ships it is deadweight at the summer load line. For container ships it is 70% of deadweight, a convention carried over from EEDI to reflect that boxes cube out before they weigh out, so a container ship rarely sails at full deadweight. For passenger and ro-ro passenger ships it is gross tonnage, because those ships earn transport work from people and lane-metres rather than cargo mass. Picking the wrong capacity basis shifts the attained value by the full ratio of the two numbers, which on a container ship is a 30% error in either direction.

The reference loading condition pairs with the capacity definition. The speed-power curve has to be taken at the loading the capacity figure assumes, in deep, calm water, with the hull and propeller clean. A curve taken light or in a model basin still has to be corrected to that reference condition before it feeds $V_{ref}$. The technical file documents which curve was used and how it was corrected, because the surveyor verifies the chain from the curve to the declared reference speed.

Innovative-technology and shaft-motor credits

The numerator carries two credit terms that lower the attained value. The first credits innovative energy-efficiency technology, split into categories by how the saving is realized: a category that cuts main-engine power, a category that supplies electrical power, and a category that does both. Waste-heat recovery, wind-assist rotors and sails, solar arrays feeding the auxiliary load, and air-lubrication systems each book a credit sized to the power they save or supply, verified by trial or by a recognized calculation method. The second term credits a shaft motor or shaft generator running as a motor, which shares propulsion load with the main engine. Each credit has to be substantiated; an unproven saving claimed in the file is the kind of thing a recognized organization sends back.

A worked sense of the numbers

Take a Panamax bulk carrier of about 82,000 tonnes deadweight with a single two-stroke main engine rated at 9,500 kW MCR. At 75% MCR the as-built ship makes around 14.2 knots. Run through the EEDI arithmetic at heavy fuel, with a typical specific fuel consumption near 175 g/kWh and the auxiliary estimate, the attained value lands a few percent above the required EEXI for a bulk carrier of that size. Apply an Engine Power Limitation to 75% of the original MCR, so the new limited MCR is about 7,100 kW, and recompute: the 83% and 75% power points both drop, $V_{ref}$ falls to roughly 13.4 knots, and because the speed term sits in the denominator while the limited power sits in the numerator, the ratio crosses below the required value. The ship complies with no hull work and no fuel change, having capped a power band it spent most of its life below. The EEXI Attained calculator reproduces this kind of before-and-after in seconds; the EPL calculator returns the power fraction needed to close a given gap.

The required EEXI and reduction factors

The required EEXI is the target. It is the EEDI reference line value for the ship’s type and size, discounted by a one-off reduction factor.

The reference line itself is the parameter set $a \cdot b^{-c}$ adopted for EEDI, where $b$ is the ship’s deadweight (capacity) and the coefficients $a$ and $c$ are tabulated by ship type. Resolution MEPC.328(76) carries the EEXI-specific reference parameters and reduction factors in the Regulation 25 tables. The reduction factor X is applied once and does not tighten over time the way the EEDI phase factors do.

The reduction factor scales with how much room a type was judged to have. The headline figures: bulk carriers, gas carriers, tankers, & container ships above the larger size thresholds carry reduction factors in the 15% to 50% band depending on size, with the largest container ships and the largest bulkers and tankers at the high end. General cargo ships sit lower. Ro-ro cargo and ro-ro passenger ships, where the EEDI reference line is already loose and the design margins thin, carry the smallest reductions. LNG carriers and cruise ships with non-conventional propulsion have their own factors set against their own reference lines. The exact figure for any ship comes from the Regulation 25 table read at that ship’s deadweight, which the EEXI Required calculator resolves for you once you enter the type and capacity.

Compliance is a single inequality: attained EEXI at or below required EEXI. The gap between a ship’s as-built attained value and its required value is the design debt the owner has to close, on paper, by the first survey window. For a large slice of the existing fleet, ships delivered between roughly 2009 and 2015 that were already reasonably efficient, that gap was 5% to 15%. For older or faster designs it ran wider.

How the reference line works

The reference line is the same curve EEDI used, fitted to a sample of ships built around 1999 to 2009 so that a value on the line represents the average efficiency of that earlier fleet for a given type and size. It takes the form $a \cdot DWT^{-c}$, where the negative exponent means larger ships sit lower on the line per tonne-mile, because a bigger hull moves more cargo for proportionally less power. A small bulker and a Capesize face different absolute required EEXI values from the same percentage reduction factor, because the reference line already places them at different starting points. The required EEXI for any ship is therefore two lookups and one multiplication: read the line at the ship’s deadweight, read the reduction factor for the type and size band, and apply it. The EEXI Required calculator does both lookups against the Regulation 25 tables.

The reduction factor is where the regulatory judgment sits. A type with a loose reference line and thin design margins, ro-ro and ro-pax, was given a small factor because the IMO judged there was little headroom to take. A type with a tight reference line and historically generous installed power, large containerships and large tankers, was given a larger factor because the modeling said the efficiency was there to be recovered. The factor does not change after adoption; unlike EEDI, EEXI has no Phase 2 or Phase 3 step-down.

The two compliance routes

There are two families of response, and most owners chose the cheaper one.

The technical route reduces the attained value through hardware or fuel. Engine derating, applied as an Engine Power Limitation or a Shaft Power Limitation, cuts the reference power and the reference speed in one move and is by far the most common single action. Waste-heat recovery systems feed shaft or electrical power back and book a numerator credit, which suits container ships with long, steady sea legs. Propulsion-improvement devices, the pre-swirl stators, rudder bulbs, Mewis-type ducts, and bulbous-bow reshaping, shave 2% to 6% off required power and feed the gain into both EEXI and the ongoing CII. A fuel switch changes $C_F$: moving a dual-fuel ship to LNG cuts the carbon factor from 3.114 to 2.750, a 12% drop in that term, and addresses FuelEU Maritime and CII at the same time.

The other route is to accept the limitation and declare it. An owner who already runs a bulker or tanker at 65% to 70% MCR in practice loses little real capability by capping the engine at that level, so an EPL or ShaPoLi declaration with no other change is the whole compliance package. It costs the installation of a limiter or a torque-measurement system plus the class attendance, and nothing in fuel terms, because it caps a power band the ship rarely used. That is why power limitation, not retrofitting, became the dominant EEXI response across the dry-bulk and tanker fleets.

The choice turns on the trade. A ship that needs reserve power for weather routing, schedule recovery, or fixed-window port calls pays a real operational price for a tight EPL. A ship in a slow, steady trade pays almost nothing. The reserve-power question is the one genuine controversy in the EEXI design, & it sits in the Limitations section below.

A point worth keeping straight: power limitation changes the maximum the ship can develop, not the efficiency at any given speed. The hull pushes through the same water with the same resistance at 12 knots whether the engine is capped at 65% MCR or free to 100%. An EPL doesn’t make the ship more efficient; it removes the top of the speed range. Hardware measures, a pre-swirl stator or a fuel switch, change the efficiency at every speed and so move both EEXI and CII. That is the whole reason the two routes diverge in their effect on real emissions.

Engine Power Limitation versus Shaft Power Limitation

Both EPL and ShaPoLi cap the power the ship can develop so the reference speed used in the attained EEXI falls to a compliant level. They differ in where the cap is applied and how it is enforced.

An Engine Power Limitation caps the main-engine output, usually by limiting the fuel index or scavenge-air settings in the engine control system so the engine cannot exceed the declared limited MCR. It is set, sealed, and recorded. The limited MCR becomes the new ceiling for the EEXI calculation and for the certificate.

A Shaft Power Limitation caps power at the shaft instead. It uses torque and rpm instrumentation on the propeller shaft, multiplies the two to get shaft power, and trips or alarms when the limit is reached. ShaPoLi is mechanically less invasive than an EPL because it doesn’t touch the engine’s own control settings, so it suits ships whose engine has no OEM-approved EPL kit, or owners who want to retain the engine’s full unrestricted capability behind a software gate. Resolution MEPC.335(76) governs both systems, sets the documentation requirements, and defines the override.

The override and the overridable distinction

The override is the feature that makes power limitation acceptable to flag states and class societies on safety grounds. Resolution MEPC.335(76) allows the limit to be exceeded to secure the safety of the ship or to save life at sea: heavy weather, ice, search and rescue, evasive action. There are two declared system types. An overridable system lets the master release the limit when needed; the release is automatically logged, time-stamped, and reported to the flag administration, and the seal is broken and then re-sealed at the next survey. A non-overridable system has no release path and is treated as a hard mechanical or electronic cap, which a few owners prefer because it removes any question about whether the limit is real.

The override log is the audit trail. Every release of an overridable EPL or ShaPoLi has to be recorded with the reason, the duration, and the power reached, and reported so the administration can see the limit isn’t being defeated as a matter of routine. A pattern of overrides outside genuine safety conditions is a non-compliance, not a loophole. That reporting obligation is what keeps the declared limited MCR honest against the installed MCR.

In practice the log entry records the date and time of release, the duration the limit was exceeded, the maximum power reached, and the reason in the master’s words, with the flag administration notified per the procedure in the Onboard Management Manual. A port-state control officer who finds frequent releases with thin justifications can treat the limitation as effectively defeated, which puts the attained EEXI the certificate rests on in doubt. The seal, the log, and the manual are checked together: a sealed limiter with an empty log and an intact seal is the normal state, and a broken seal with no corresponding logged release is the finding nobody wants.

The Onboard Management Manual

A ship with an EPL or ShaPoLi has to carry an Onboard Management Manual for the power-limitation system, also required by Resolution MEPC.335(76). The manual describes the system, the set-point, the override procedure, the recording and reporting steps, & the responsibilities of the crew. It is the operational counterpart to the technical file: the technical file proves the limit was set correctly, the manual tells the crew how to live with it and how to use the override without breaking the regime. Class surveyors check both at the EEXI survey and verify the seal or the software state at later annual surveys.

Survey, certification, and the EEXI Technical File

EEXI compliance is documented in an EEXI Technical File, prepared by the owner or a recognized organization and verified by the Administration or the class society acting on its behalf. The file carries the ship particulars, the engine and auxiliary data, the speed-power curve, the reference speed, the attained EEXI calculation, the required EEXI target, and where a limitation is used, the limited MCR and the EPL or ShaPoLi details. The survey and certification process is set by Resolution MEPC.334(76).

The verification is a one-time survey, conducted at or before the first annual, intermediate, or renewal IAPP survey on or after 1 January 2023. The surveyor checks the technical file, witnesses or verifies the power-limitation set-point and seal where one exists, and confirms the attained value meets the required value. On a pass, the ship’s International Energy Efficiency Certificate (IEE Certificate), the same certificate that already carried the EEDI endorsement for newer ships, is amended to record EEXI compliance. There is no separate EEXI certificate; the IEE Certificate is the single document that now carries both the design indices and, by reference, the SEEMP that drives CII.

After that survey the EEXI design check is closed. There is no annual EEXI recalculation. What the annual surveys do verify, for a ship using power limitation, is that the EPL or ShaPoLi seal is intact and the override log is being kept, because a defeated limiter would invalidate the attained value the certificate rests on. A major conversion that changes engine power, capacity, or the speed-power relationship reopens the calculation and requires a fresh EEXI verification, because the inputs the original file was built on no longer hold.

Who verifies, and the document chain

The Administration is the flag state, and in practice it delegates the EEXI verification to a recognized organization, almost always the ship’s classification society acting under authorization. The verifier checks that the technical file is internally consistent, that the speed-power curve supports the declared reference speed, that the specific fuel consumption matches the NOx Technical File where one exists, and that any innovative-technology or shaft-motor credit is substantiated. For a power-limited ship the verifier also confirms the limiter is installed and set to the declared limited MCR, witnesses or accepts evidence of the seal, and checks the Onboard Management Manual is aboard. The IEE Certificate endorsement is the visible output; the technical file is the evidence behind it, and a port-state control officer can ask to see both. A technical file that doesn’t reconcile, a missing override log, or a broken seal with no logged release are the findings that turn up at inspection.

The certificate ties back to the wider Annex VI document set. The IEE Certificate sits alongside the IAPP Certificate, the NOx Technical File, the Bunker Delivery Notes, and the SEEMP, which now carries Part II for the Data Collection System and Part III for the CII plan. EEXI is the design entry in that file; the SEEMP and the reported fuel data are the operational entries that feed CII. A ship can hold a clean EEXI endorsement and still draw a D or E carbon-intensity rating, because the two are measuring different things on the same hull.

The one-time check versus the annual CII cycle

The structural difference between EEXI and CII is worth stating plainly, because it drives how owners spend money. EEXI is a design parameter: compute it, prove it, certify it, done. A ship can satisfy EEXI on paper through an EPL declaration without ever burning a litre less fuel, because the index measures a modeled reference condition, not real consumption. That is not a flaw in the ship’s behavior; it is what a design index measures.

CII is the opposite. The Carbon Intensity Indicator, also in the 2021 Annex VI package, takes the fuel a ship actually reported under the IMO Data Collection System and the distance it actually sailed, computes the operational carbon intensity, and grades the ship A to E against a line that tightens every year through at least 2030. A D rating for three consecutive years, or a single E, triggers a corrective action plan in the SEEMP. You can’t satisfy CII with paperwork; you have to burn less or sail more productively. EEXI is the floor the design has to clear once; CII is the treadmill the operation runs on for the life of the ship.

The two interact. The same physical measures that improve EEXI, slower steaming, propulsion-improvement devices, waste-heat recovery, a cleaner fuel, also improve CII. An owner who closes the EEXI gap with a pure EPL declaration has done nothing for CII and still faces the annual grade. An owner who closes it with a hydrodynamic retrofit or a fuel switch has bought down both at once. That asymmetry is why the cheapest EEXI route and the smartest fleet-decarbonization route are often not the same route.

Interaction with EEDI, CII, EU ETS, and FuelEU

EEXI sits inside a stack of overlapping efficiency and carbon regimes, and the inputs cross over. EEDI and EEXI share the calculation family, so a ship that already holds an EEDI value close to or below its EEXI target needs little or no further action; the EEXI gate was sized so that ships meeting EEDI Phase 2 or Phase 3 would generally clear it. Older ships built before EEDI applied carry no design index at all and are where the EEXI gap was widest.

CII reads the operational outcome and runs annually. The European measures add a financial and a fuel-quality layer on top.

The fuel data both systems read comes from the same source. The IMO Data Collection System has required ships above 5,000 GT to report annual fuel oil consumption, by fuel type, and distance and hours under way since calendar year 2019, with the data verified by the Administration and submitted to the IMO Ship Fuel Oil Consumption Database. CII is computed from that exact dataset, which is why an owner can’t massage the CII grade after the fact: the numbers are already filed. EEXI, by contrast, never touches reported consumption; it reads a modeled reference condition. So a ship reports real fuel for CII every year while its EEXI sits frozen on a 2023 calculation that assumed a single calm-water point. The two regimes coexist on one hull without sharing a single measured value. The EU Emissions Trading System brought shipping into its scope from 1 January 2024, phasing in surrendered allowances for CO2 emitted on voyages touching the EEA, which puts a direct price on the fuel an EPL-limited ship still burns. FuelEU Maritime, applying from 1 January 2025, sets a declining limit on the greenhouse-gas intensity of the energy a ship uses in EEA-related voyages, which rewards exactly the fuel switches that also lower the EEXI carbon factor. A ship that met EEXI through an LNG or methanol conversion is positioned for FuelEU; a ship that met it through a sealed EPL is not. The regimes don’t share a single number, but they push the same hardware and fuel decisions, which is why owners increasingly model EEXI, CII, EU ETS exposure, and FuelEU together rather than one at a time.

Charter-party consequences

An EPL or ShaPoLi caps the maximum speed the ship can warrant. A vessel that previously warranted 14.5 knots at 80% MCR on a charter may only reach 13 knots once the engine is sealed at 65% MCR. That changes the performance warranty, the speed-and-consumption table, and any under-performance claim built on the old figures. BIMCO published an EEXI Transition Clause to handle the handover: it sets out how warranted speeds, performance claims, and under-performance damages adjust once the limitation is declared, so the cap doesn’t expose the owner to claims under a warranty the ship can no longer physically meet. Charters fixed after the EEXI survey increasingly state the limited MCR directly rather than a bare speed warranty, which removes the ambiguity at the source.

Limitations

EEXI is a design check, not an operational one, and that defines what it can and can’t do. The attained value is computed at a single reference loading condition, a single reference speed point, and a single assumed fuel, in calm deep water. It says nothing about real voyages, real weather, real cargo factors, or real fuel actually burned. A ship can hold a compliant EEXI and still operate inefficiently in service; the index was never built to catch that, which is the role CII fills.

Compliance can be satisfied on paper. Because the cheapest route is an Engine Power Limitation or Shaft Power Limitation that caps a power band many ships rarely used, an owner can pass EEXI without reducing actual fuel burn at all. The index therefore does not, by itself, cut emissions for ships that already operated below their installed power. Its real-world effect is to remove the option of running fast, not to force a ship that ran moderately to run slower still.

The limitation is overridable. An overridable EPL or ShaPoLi can be released for safety, and while every release is logged and reported under Resolution MEPC.335(76), the cap is a declared restriction rather than a permanent physical change to the engine. The enforcement rests on seals, software state, and the override log being checked at survey, not on the engine being incapable of more.

The reserve-power debate is unresolved. Critics argue that aggressive power limitation strips margin a ship needs for heavy weather, schedule recovery, or evasive maneuvering, and that a tightly capped ship is less safe in adverse conditions. The override mechanism is the IMO’s answer, but it depends on the master releasing power in time and on the system being genuinely available, and a non-overridable installation has no release at all. The trade-off between a tight EEXI margin and operational reserve is a live engineering and safety judgment, not a settled question.

It is a one-off, not a trajectory. EEXI applies its reduction factor once and then sits frozen for the life of the ship, where EEDI tightens by phase for new builds and CII tightens annually. An existing ship that just cleared EEXI in 2023 faces no further EEXI pressure, even as the rest of the regulatory stack keeps ratcheting around it. The index closed a gap in the design framework; it is not, on its own, a decarbonization curve.

The numbers depend on inputs that can be soft. The reference speed comes from a speed-power curve that may rest on a sea trial decades old or on a model test, and the specific fuel consumption comes from a test-bed value that drifts as the engine ages. Two competent engineers can produce attained EEXI values that differ by a few percent on the same ship from defensible but different source data, which is why the technical file and the recognized-organization verification matter as much as the formula.

See also

Calculators

• EEXI Attained Calculator (MEPC.328(76))
• EEXI Required Calculator (MEPC.328(76))
• EPL: Engine Power Limitation for EEXI
• ShaPoLi: Shaft Power Limitation for EEXI
• EEDI Attained Calculator (MEPC.328(76))
• MARPOL Annex VI: EEXI Required Index

Related wiki articles

• What is EEDI? Energy Efficiency Design Index explained
• What is CII? Carbon Intensity Indicator explained
• What is AER (Annual Efficiency Ratio)?
• MARPOL Annex VI: air pollution and energy efficiency

Related calculators

• EEOI: Energy Efficiency Operational Indicator
• AER: Annual Efficiency Ratio
• ShaPoLi: Shaft Power Limitation for EEXI
• EPL: Engine Power Limitation for EEXI
• VFD Energy Saving: Cube-Law Pump
• Brayton Cycle: Gas Turbine Efficiency