IMO Global Fuel Standard: How Attained GFI Is Calculated

The IMO global fuel standard is the label for the fuel-intensity requirement in draft regulations 33 to 36 of a new MARPOL Annex VI Chapter 5, the legal text of the IMO Net-Zero Framework . It requires each ship of 5,000 GT and above to calculate an attained annual GHG fuel intensity (GFI), the energy-weighted well-to-wake greenhouse gas intensity of everything it used on board in a calendar year, in gCO2eq/MJ. The ship then compares that figure with two targets and balances any gap with remedial units or surplus units.

The requirement is a draft. MEPC 83 approved it on 11 April 2025, the extraordinary session convened to adopt it adjourned in October 2025, and MEPC 84 in April and May 2026 did not adopt it. The name is not in the text either: “Global Fuel Standard” and “GFS” occur nowhere in IMO document MEPC/ES.2/2. The label comes from IMO’s 11 April 2025 press briefing, which used “global fuel standard” as a heading for the requirement that ships “reduce, over time, their annual greenhouse gas fuel intensity (GFI)”. FuelEU Maritime Article 30(5) refers to “a global GHG fuel standard”.

What the IMO global fuel standard requires of a ship

The fuel standard reduces to five steps, each in a numbered draft regulation:

1. Record the energy. Log every fuel burned by type and every non-fuel energy source used on board over the calendar year (regulations 33.1 and 37, appendix XII).
2. Attach an intensity to each fuel. Take a well-to-wake emission intensity for each fuel from the MEPC.391(81) LCA Guidelines defaults or from a certified fuel lifecycle label (regulation 34).
3. Compute the attained annual GFI. Divide the energy-weighted sum of intensities by total energy (regulation 33.2).
4. Compare with the targets. Set the attained GFI against the year’s base target and direct compliance target from Table 4 (regulation 35).
5. Balance the result. Convert the gap into tonnes of CO2eq and settle it with remedial units, surplus units, or both (regulation 36), then obtain a Statement of Compliance (regulations 6.9 and 37.6).

What the ship is judged on is the carbon content of its energy, not its speed, its cargo or its design. That separates the fuel standard from the carbon intensity indicator in Chapter 4, which divides CO2 by transport work, and from the design indices EEDI and EEXI . All three would continue alongside it.

Where the IMO global fuel standard sits in draft MARPOL Annex VI Chapter 5

Draft Chapter 5 is headed “Regulations on the IMO Net-Zero Framework” and runs from regulation 30 to regulation 44. Regulation 32 sets its two functional requirements: GFI improvement “in accordance with regulation 35”, and GHG emissions pricing and ZNZ rewards “in accordance with regulations 36 and 39”. The fuel standard is the first of those, with the pricing attached through the balancing rules.

Earlier drafts and many secondary sources placed the framework in a “Chapter 4 ter” with regulation numbers such as “28ter” or “31ter”. Those numbers do not exist in the approved text. Chapter 4 of the draft revised Annex VI keeps the energy efficiency regulations: the EEDI, the EEXI, the SEEMP , fuel consumption reporting in regulation 27 and the CII in regulation 28.

Draft regulation 30 applies Chapter 5 to ships of 5,000 gross tonnage and above, excluding ships solely on voyages within waters of their own flag State, ships not propelled by mechanical means, platforms including FPSOs, FSUs and drilling rigs, and semi-submersible vessels until further review. The fleet in scope is broadly the fleet that already reports to the IMO Data Collection System .

Attained annual GFI under draft regulation 33

The attained annual GFI is the ship’s energy-weighted average well-to-wake GHG intensity over one calendar year. Draft regulation 2.3.1 defines it, and regulation 33.2 gives the formula:

In this formula \( j \) is the fuel type, summed over the fuels “as reported to the IMO Ship Fuel Oil Consumption Database”. \( \text{EI}_j \) is the emission intensity of fuel \( j \) in gCO2eq/MJ “on a well-to-wake basis”, determined under guidelines that footnote 80 identifies as MEPC.391(81) “as may be amended”. \( \text{Energy}_j \) is the energy supplied by that fuel, and \( \text{Energy}_{\text{total}} \) is all energy used on board.

Energy of each fuel

The draft writes the formula in energy, not mass. In practice a ship’s records hold fuel mass, so the energy of each fuel is its mass times its lower calorific value (LCV):

with \( M_j \) in grams and \( \text{LCV}_j \) in MJ/g, as MEPC.391(81) tabulates it. That step is a derivation, not a line of regulation 33. The LCV is the default in MEPC.391(81) Appendix 2 unless a certified value applies: 0.0402 MJ/g for the VLSFO pathway and 0.0427 MJ/g for marine gas oil, for example. Ten thousand tonnes of VLSFO therefore supply \( 10{,}000 \times 10^{6} \times 0.0402 = 402{,}000{,}000 \) MJ.

A lower calorific value is used throughout, not a higher one. The water formed in combustion leaves as vapor, so the LCV is the energy a marine engine can actually use, and it is the basis of both the IMO and the FuelEU Maritime intensity calculations.

Shore power, wind and solar in the energy total

Draft regulation 33.2 defines \( \text{Energy}_{\text{total}} \) as “including but not limited to fuel oil, electricity delivered from shore power, and zero-emission energy sources, such as wind propulsion and solar power”. Energy from those sources therefore enters the denominator, and to the extent its intensity is below the fuel mix, it lowers the attained GFI.

• Shore power. Onshore power supply takes a default intensity equal to the national grid intensity under MEPC.391(81) paragraph 9.23, so its benefit depends on where the ship plugs in.
• Wind and solar. Wind-assisted propulsion and solar panels are named in the definition, but \( \text{EI}_j \) is defined per fuel type, and the draft does not say how a rotor sail’s contribution is measured or entered. Footnotes 78 and 79 leave the method to GFI calculation guidelines “to be developed”.
• Batteries and fuel cells. Appendix XII asks for their capacity, recorded in MJ.

A practitioner cannot yet claim a wind-propulsion credit under the fuel standard, because the guidelines that would define it do not exist. The same gap is on the EU side: FuelEU Maritime Article 30(2)(h) lists wind as an item for the Commission’s review report due by 31 December 2027.

Data behind the calculation

Draft regulation 33.1 draws on two data sets: the fuel oil consumption data already reported under regulation 27, and the additional Chapter 5 data under regulation 37 in the format of appendix XII. Appendix XII asks for:

• fuel consumption by type and by consumer (main engines, auxiliary engines, boilers, others);
• the capacity of fuel cells, batteries, wind propulsion and photovoltaic systems, recorded in MJ;
• total onshore power supply received, in kWh;
• the fuel lifecycle label reference for each certified fuel;
• \( \text{EI}_j \), \( \text{Energy}_j \) and \( \text{Energy}_{\text{total}} \);
• the base and direct compliance targets, the compliance balance, the Tier 1 and Tier 2 deficits, banked surplus units and ZNZs used.

Draft regulation 26.4.1 requires the SEEMP, on or before 1 January 2028, to include the methodology for collecting that data and the processes for reporting it. The fuel supplied to the ship is documented on the bunker delivery note under regulation 18.

Well-to-wake emission intensity under MEPC.391(81)

Each fuel’s \( \text{EI}_j \) is a well-to-wake (WtW) intensity: the emissions of producing, processing and delivering the fuel to the ship, plus the emissions of using it on board. The 2024 LCA Guidelines, resolution MEPC.391(81) adopted on 22 March 2024, set the method. They revoked the 2023 guidelines in MEPC.376(80).

Well-to-tank, tank-to-wake and well-to-wake

MEPC.391(81) splits the intensity into two parts and adds them (equation 3):

The well-to-tank (WtT) part covers extraction or cultivation, processing, transport and bunkering, in gCO2eq/MJ. The tank-to-wake (TtW) part covers combustion and other use on board. For a liquid fuel with no slip, the TtW part of equation 2 reduces to

where each \( C_f \) is grams of gas emitted per gram of fuel. Paragraph 6.3 builds the WtW value on the second of the two TtW values in section 5.3, the one that counts the biogenic carbon credit. The full equation 2 also carries terms for fuel slipped unburned, fugitive emissions and carbon captured on board; the next section covers them.

The article on well-to-wake fuel pathways sets out the pathway codes, and well-to-wake intensity covers the concept across regimes.

Greenhouse gases and GWP weights

Three gases count: CO2, methane and nitrous oxide. Draft regulation 2.3.2 defines CO2eq on 100-year global warming potentials from the IPCC Fifth Assessment Report, and MEPC.391(81) footnotes 9 and 10 fix them at 28 for CH4 and 265 for N2O (AR5 GWP100 in maritime rules ).

Paragraph 2.1 puts black carbon, SOx, particulate matter and non-methane volatile organic compounds outside the scope. A scrubber, a low-sulphur fuel or a particulate filter therefore does nothing to a ship’s attained GFI, however much it changes its sulphur compliance position.

Methane slip, fugitive emissions and carbon capture

Methane slip is where the TtW term diverges most between engines burning the same fuel. MEPC.391(81) handles it with a slip coefficient, \( C_{\text{slip}} \), as a percentage of fuel mass, and sets the fossil LNG \( C_{f,\text{CH4}} \) to zero so the slip is not counted twice (footnote 8). The default slip values are 3.5 percent for an Otto-cycle medium-speed engine, 1.7 percent for Otto-cycle slow-speed, 0.15 percent for diesel-cycle slow-speed and 2.6 percent for a lean-burn spark-ignited engine (methane slip and N2O ).

Two further terms are present and switched off:

• Fugitive emissions from fuel handling, \( C_{fug} \), are set to zero by footnote 7.
• Carbon captured on board, the \( SF_{ccu} \cdot e_{ccu} \) and \( e_{OCCS} \) terms, are set to zero by footnotes 11 to 13 until guidance on onboard carbon capture is developed.

Nitrous oxide matters most for ammonia. An ammonia engine emits no CO2 from its fuel, so its whole TtW value rests on N2O and on any pilot fuel, each weighted at 265 (N2O emissions from marine engines ).

MEPC.391(81) Appendix 2 default values

Appendix 2 is the default table. It lists 14 pathway codes and prints components, not a finished well-to-wake figure. The values below are those Appendix 2 prints; the WtW column is this site’s arithmetic on them with the GWP weights above.

The oil pathways carry \( C_{f,\text{CH4}} = 0.00005 \) and \( C_{f,\text{N2O}} = 0.00018 \) g/g. Fossil LNG carries \( C_{f,\text{CH4}} = 0 \), with the slip coefficient taking its place, and \( C_{f,\text{N2O}} = 0.00011 \). For the biofuels, the WtW value depends on the biogenic carbon treatment of paragraph 6.3 and on the certified feedstock, so this site does not derive one from the default row. The per-fuel articles give the pathway detail: HFO , VLSFO and MGO , FAME , HVO , fossil LNG and bio-LNG .

Fuels with no usable default

Appendix 2 contains no methanol row at all. Fossil LNG, bio-LNG, LPG, hydrogen and ammonia appear with physical properties but without a numeric well-to-tank default. For all of these, a ship has no complete IMO default to put into regulation 33.2 today, and the working route is a certified value under regulation 34 (methanol grades , ammonia grades , hydrogen , e-fuels ).

That gap is why tables of “IMO default” intensities for grey, blue and green methanol or ammonia cannot be traced to MEPC.391(81). MEPC.391(81) paragraph 13.2 provides for continuous review of Appendix 2, and the IMO summary of ISWG-GHG 22 records that the LCA agenda item was deferred to ISWG-GHG 23, with a further report of the GESAMP LCA working group expected at MEPC 85.

Certified actual values under draft regulation 34

A ship does not have to use the default. Draft regulation 34 takes each fuel’s emission intensity from emission factors and fuel lifecycle label (FLL) metrics, and an FLL certified by a recognized sustainable fuels certification scheme (SFCS) carries an actual value for that fuel’s pathway. MEPC.391(81) paragraph 10.1 makes actual emission factors “subject to verification and certification by a third party”.

The regulation 34 mechanics:

• The FLL “may accompany” the bunker delivery note under regulation 18; it does not replace it.
• The Committee recognizes each SFCS, and recognition is renewed every five years.
• The Secretary-General is to publish the list of recognized schemes by 1 March 2027.
• Recognized schemes report to the Organization from the end of 2027.

A biofuel from waste feedstock and one from a crop pathway can sit on the same bunker specification and carry very different certified intensities. Without an FLL, a methanol or ammonia cargo has nothing to put into \( \text{EI}_j \) at all, because Appendix 2 prints no complete default for either (biofuels in shipping , methanol as marine fuel , ammonia as marine fuel , hydrogen as marine fuel ).

Target annual GFI: the two benchmarks

Draft regulation 35 sets two targets per calendar year, which regulation 2.3.18 calls together the target annual GFI. Each is a reduction from a reference value of 93.3 gCO2eq/MJ well-to-wake, “representing the average GFI of international shipping in year 2008”:

Table 4 prints factors for each year from 2028 to 2035. Regulation 35.3 fixes the 2040 base factor at 65 and leaves 2036 to 2040 to the Committee by 1 January 2032. The draft has no 2027 value, no 2050 value and no interpolation rule. The full table and its derivation are in the GFI reduction trajectory .

The base target is the looser bound and the direct compliance target the stricter one. In every year of Table 4 the direct compliance factor is 13.0 points above the base factor, so the band between them is 12.129 gCO2eq/MJ wide. The two targets have articles of their own: the base target annual GFI and the direct compliance target annual GFI .

GFI compliance balance and deficits under draft regulation 36

Draft regulation 36 turns the gap between a ship’s attained GFI and its targets into tonnes of CO2eq. The benchmark for the balance is the direct compliance target, not the base target.

The GFI compliance balance

Regulation 36.1 defines the balance as:

A balance of zero or more means direct compliance, and regulation 36.11 issues surplus units equal to it. A negative balance is a compliance deficit (GFI compliance balance ). The draft states the result “in tonnes of CO2eq” without writing the conversion factor. gCO2eq/MJ multiplied by MJ gives grams, so a practitioner divides by \( 10^{6} \).

A positive balance is a surplus. A spreadsheet that computes attained minus target will reverse every sign.

Tier 1 and Tier 2 deficits

Regulation 36.4 splits a deficit by where the attained GFI falls:

The labels run against intuition. Exceeding the looser base target creates the Tier 2 deficit, which is priced higher. The band between the two targets always produces the Tier 1 deficit first. Draft text writes the regulation 36.4 terms as (DCT minus attained) and so on, giving negative numbers; the table states them as positive quantities owed.

Remedial units

Regulation 36.5 allows a Tier 1 deficit to be balanced only by Tier 1 remedial units. Regulation 36.6 allows a Tier 2 deficit to be balanced by any mix of:

1. surplus units transferred from other ships;
2. the ship’s own banked surplus units;
3. Tier 2 remedial units.

Remedial units are acquired through GHG emissions pricing contributions to the IMO Net-Zero Fund and are non-transferable under regulation 2.3.11. For reporting periods 2028 to 2030, regulations 36.8 and 36.9 set the initial prices at USD 100 per tonne CO2eq for Tier 1 and USD 380 for Tier 2, well-to-wake. Regulation 36.10 requires the Committee to adopt the price mechanism for later periods by 1 January 2028; no price exists for 2031 onward (remedial units , IMO levy and economic measure ).

Surplus units

A ship in direct compliance receives surplus units, and regulation 2.3.16 makes them transferable. Under regulations 36.12 to 36.15 each surplus unit can be used once, in one of three ways: transferred to another ship to balance that ship’s Tier 2 deficit, banked, or cancelled voluntarily. A unit not assigned to a use is banked automatically. It stays valid for two calendar years following the year of issue, and an unused unit is then cancelled “as a mitigation contribution” (surplus units ).

The transfer carries no condition of common ownership, management or fleet. A surplus unit can move to any ship in scope with a Tier 2 deficit, and the price is a private matter. The Tier 2 remedial unit price caps what a buyer would rationally pay, because every surplus unit displaces a USD 380 remedial unit in 2028 to 2030.

What the draft does not contain

Three mechanisms often attributed to the fuel standard are absent from MEPC/ES.2/2:

• Pooling. The word does not occur in the draft. There is no fleet-level balance of the kind FuelEU Maritime allows under Article 21 of Regulation (EU) 2023/1805 (FuelEU compliance balance and pooling ).
• A secondary market in remedial units. Remedial units are non-transferable, so they cannot be sold on.
• Surplus units against a Tier 1 deficit. Regulation 36.5 excludes it.

Cost recovery and operational responsibility

Regulation 36.7 provides that a ship that has balanced its deficit “shall be considered as being compliant”, without prejudice to the recovery of costs from the entity responsible for operational decisions, naming fuel, cargo, route or speed. The regulation preserves a right of recovery without creating one. Whether an owner can pass remedial unit costs to a time charterer that ordered the bunkers depends on the time charter party . Clauses drafted for the CII, such as the BIMCO CII clauses , allocate responsibility for a rating, not for remedial units or surplus units.

ZNZ rewards under draft regulation 39

Zero or near-zero GHG emission technologies, fuels and energy sources (ZNZs) are eligible for rewards from the Net-Zero Fund under draft regulation 39. Draft regulation 39.1 sets the threshold at a GFI “not greater than 19.0 gCO2eq/MJ” until 31 December 2034 and “not greater than 14.0” from 1 January 2035. Those values are about 80 and 85 percent below the 93.3 reference value, and below every Table 4 target (ZNZ rewards ).

Regulation 39.3 requires the Committee to define the reward and its methodology by 1 March 2027 and to review it every five years. The approved text holds no reward amount. Regulations 40 and 41 establish the IMO Net-Zero Fund, which receives the regulation 36 contributions and disburses them for rewards, just transition purposes and administration (Net-Zero Fund disbursement ). The Registry records ZNZ energy use and avoided emissions under regulation 38.6, and the verifier checks them under regulation 6.9.

A fuel certified just under 19.0 gCO2eq/MJ earns ZNZ status and brings the ship’s attained GFI down in proportion to its energy share. For a ship otherwise on VLSFO at 95.48 gCO2eq/MJ, reaching the 2028 base target of 89.568 takes about a 7.7 percent energy share of such a fuel, and reaching the direct compliance target of 77.439 about 23.6 percent. Those shares are this site’s arithmetic on regulation 33.2.

Attained GFI worked example: a two-fuel ship in 2028

This example applies regulations 33 and 36 to one ship for calendar year 2028, using MEPC.391(81) default factors. The well-to-wake intensities are derived by this site from the Appendix 2 components; MEPC.391(81) prints no WtW totals.

Fuel. The ship burns 8,000 tonnes of a VLSFO-grade HFO pathway and 2,000 tonnes of DMA marine gas oil. It uses no shore power, wind or other energy.

Intensities. VLSFO: TtW \( = (3.114 + 28 \times 0.00005 + 265 \times 0.00018)/0.0402 = 78.684 \), WtW \( = 78.684 + 16.8 = 95.484 \) gCO2eq/MJ. MGO: TtW \( = (3.206 + 0.0014 + 0.0477)/0.0427 = 76.232 \), WtW \( = 76.232 + 17.7 = 93.932 \) gCO2eq/MJ.

Energy. VLSFO: \( 8{,}000 \times 10^{6} \times 0.0402 = 321{,}600{,}000 \) MJ. MGO: \( 2{,}000 \times 10^{6} \times 0.0427 = 85{,}400{,}000 \) MJ. Energy_total is 407,000,000 MJ.

Attained GFI.

Balance. \( (77.439 - 95.158) \times 407{,}000{,}000 \) MJ \( = -7{,}211.8 \) t CO2eq. The ship is above the base target of 89.568, so both deficits arise:

• Tier 1: \( (89.568 - 77.439) \times 407{,}000{,}000 \) MJ \( = 4{,}936.5 \) t CO2eq, balanced only by Tier 1 remedial units at USD 100, or USD 493,650.
• Tier 2: \( (95.158 - 89.568) \times 407{,}000{,}000 \) MJ \( = 2{,}275.3 \) t CO2eq, balanced by surplus units bought from other ships or by Tier 2 remedial units at USD 380, a ceiling of USD 864,600.

The two deficits add up to the negative balance. Paid entirely in remedial units, the 2028 bill is about USD 1,358,300. On the same fuel in 2030, when the base target falls to 85.836, the Tier 2 deficit grows to about 3,794.2 t and the bill to about USD 1,935,400 at the same prices.

Adding a certified biofuel

Suppose the ship replaces 1,500 tonnes of its VLSFO with a biofuel carrying a certified FLL intensity of 30.0 gCO2eq/MJ and the FAME default LCV of 0.0372 MJ/g. The 30.0 figure is an assumption for the example, not a default: the value a real cargo carries depends on its certified pathway.

• Energy: VLSFO 6,500 t gives 261,300,000 MJ; MGO 85,400,000 MJ; biofuel 1,500 t gives 55,800,000 MJ. Energy_total is 402,500,000 MJ.
• Attained GFI: about 86.08 gCO2eq/MJ, now below the 2028 base target.
• Tier 2 deficit: none.
• Tier 1 deficit: \( (86.076 - 77.439) \times 402{,}500{,}000 \) MJ \( = 3{,}476.6 \) t CO2eq, about USD 347,700 in Tier 1 remedial units.

An energy share of about 14 percent removed the Tier 2 deficit entirely and cut the 2028 bill by about USD 1 million. That leverage comes from the price gap between the tiers: the last tonnes above the base target cost 3.8 times the tonnes inside the band.

IMO global fuel standard reporting and verification under draft regulation 37

The fuel standard runs on an annual calendar fixed in draft regulation 37, with verification by the flag Administration or a recognized organization (RO).

The first reporting year is calendar 2028, so the first cycle would run from 31 March 2029 to 31 October 2029. Those dates are written into the draft on the assumption of entry into force by March 2027, and the text contains no fallback if adoption comes later.

Statement of Compliance related to annual GHG fuel intensity

The proof of compliance is the Statement of Compliance related to annual GHG fuel intensity. Under draft regulation 6.9 the Administration or RO verifies the attained GFI (regulation 33), the targets (35) and the balancing (36), reports to the Registry, checks the ship account statement and the Registry fee, verifies any ZNZ avoided emissions, and issues the Statement no later than nine months after the start of the year. Regulation 9.13 makes it valid for the calendar year of issue and the first nine months of the next, and requires it to be kept on board for five years. Its form is appendix XIII (Statement of Compliance for annual GFI ).

No “Confirmation of Continuous Compliance”, “Certified Pathway Statement” or IAPP endorsement exists in Chapter 5. The Statement is a standalone document.

Change of flag, change of company and withdrawal

A ship that changes flag or company during the year reports the partial year under draft regulations 37.2 and 37.7, and regulation 6.10 provides for the corresponding verification and Statement. Regulation 37.8 covers a ship withdrawn from service. The approved text does not set out how a partial-year balance is divided between the old and the new account.

The IMO GFI Registry

Draft regulation 38 establishes the IMO GFI Registry . Each ship needs an account by 1 October 2027, and the annual fee is due by 30 June 2028 and each 30 June after; the amount is left to the Secretary-General. Under regulation 38.4 the Registry credits surplus units, records banking and transfers, cancels surplus units that are used, voluntarily cancelled or expired, and credits and cancels remedial units on proof of payment. It is the only place a surplus unit transfer takes legal effect.

Port State control of the IMO global fuel standard

Draft regulation 10.5 allows port State control to verify “that there are valid Statements of Compliance related to … annual GHG fuel intensity” on board. That is a document check. The draft Chapter 5 does not itself set a detention ground or a penalty for a missing Statement, and it gives port States no role in the calculation (port State control ).

Verification of the calculation sits with the flag Administration or its recognized organization under draft regulation 6.9. Under MARPOL Article 16(2)(g)(ii) an Annex amendment does not enter into force for a Party that has declared, before the entry-into-force date, that it does not accept it.

GFI requirement alongside the CII, DCS and IAPP certificate

The fuel standard adds a document and a calculation; it does not replace anything in Chapter 4.

• CII. The CII in regulation 28 stays, measured in gCO2 per capacity-mile on tank-to-wake CO2 only. A ship can meet its GFI target and still receive a D or E CII rating, or the reverse (CII corrective action plan ).
• DCS. Regulation 27 fuel consumption reporting stays, and regulation 33.1 draws on it. The Chapter 5 report under regulation 37 is additional (IMO DCS and EU MRV compared ).
• IAPP certificate. Chapter 5 adds no survey item to the IAPP certificate cycle. The only survey link is the SEEMP content under regulation 26.4.1, which regulation 5.5.1 already has the initial survey of a new ship verify.

Energy efficiency still pays under the fuel standard, but through a different channel. Slow steaming leaves the attained GFI unchanged, because burning less of the same fuel does not change its intensity per MJ. It reduces Energy_total, which scales every deficit, so it cuts the remedial unit bill in proportion.

IMO global fuel standard, FuelEU Maritime and the EU ETS

A ship trading to the European Economic Area would face the IMO fuel standard alongside two EU instruments already in force. Nothing in either EU instrument or in MEPC/ES.2/2 credits one against another.

FuelEU Maritime uses its own default table, so the same bunker gives different intensities under each regime. The EU ETS maritime scope prices tank-to-wake emissions in allowances under Directive 2003/87/EC as amended by Directive (EU) 2023/959, covering CO2 and, from 2026, CH4 and N2O.

Both EU instruments carry a review clause keyed to an IMO measure. FuelEU Article 30(5) requires the Commission, in the event of the adoption by the IMO of “a global GHG fuel standard”, to report “without delay” on the articulation or alignment of the two, “including the need to avoid duplicating regulation”, with a legislative proposal where appropriate. The ETS Directive, Article 3gg(1), requires a review within 18 months of the adoption of a global market-based measure. Neither has been triggered, because nothing has been adopted, and no EU text states that IMO compliance would satisfy FuelEU (EU ETS and FuelEU double regulation , EU ETS for shipping ).

Status of the IMO Net-Zero Framework draft and its pending guidelines

The IMO global fuel standard has no legal force. MEPC 83 approved the draft on 11 April 2025 after a roll-call vote of 63 in favor, 16 against and 24 abstentions, recorded in IMO’s June 2025 submission to UNFCCC SBSTA 62. The extraordinary session, MEPC/ES.2 , adjourned in October 2025. MEPC 84, 27 April to 1 May 2026, did not adopt the draft and invited Member States to submit amendments and adjustments. ISWG-GHG 22, 1 to 4 September 2026, reached no decision on substance. MEPC 85 is scheduled for 30 November to 3 December 2026, and the resumed ES.2 for 4 December 2026, subject to MEPC 85.

Adoption would start the tacit acceptance procedure of MARPOL Article 16: deemed acceptance after a period of not less than ten months, and entry into force six months after that. IMO’s April 2025 briefing gave 16 months from adoption to entry into force, on the assumption of adoption in October 2025. The 2023 IMO GHG Strategy , MEPC.377(80), to which draft regulation 31 ties the chapter, is a recommendatory resolution and imposes nothing on a ship by itself.

Several instruments the calculation depends on do not exist yet:

• the GFI calculation guidelines under regulation 33, including the method for wind and solar (GFI calculation guidelines );
• guidelines on the recognition of SFCS and on the FLL under regulation 34;
• Registry guidelines under regulation 38;
• the ZNZ reward methodology under regulation 39.3;
• the post-2030 remedial unit price mechanism under regulation 36.10;
• guidance on onboard carbon capture, which MEPC.391(81) sets to zero until it exists.

Each of these would change the numbers a ship reports, and MEPC.391(81) Appendix 2 is itself under review.

Common attained GFI calculation errors

Pre-approval drafts and secondary sources left errors in circulation. Each is corrected against MEPC/ES.2/2 and MEPC.391(81).

• Putting mass in the denominator. Regulation 33.2 divides by energy. A mass-weighted average of intensities gives the wrong answer whenever the fuels have different LCVs, which is always.
• Leaving shore power out of Energy_total. The definition includes it, with its grid intensity in the numerator.
• Reversing the balance sign. Regulation 36.1 computes target minus attained; a positive balance means surplus.
• Using surplus units for Tier 1. Regulation 36.5 allows only Tier 1 remedial units.
• Treating remedial units as tradable. Regulation 2.3.11 makes them non-transferable.
• Quoting an IMO default for methanol. MEPC.391(81) Appendix 2 has no methanol row.
• Citing “Chapter 4 ter” or “28ter”. The framework is Chapter 5, regulations 30 to 44.
• Using a “Required GFI”. The draft terms are base target annual GFI and direct compliance target annual GFI.
• Counting black carbon or SOx. MEPC.391(81) paragraph 2.1 excludes both.
• Expecting an IAPP survey step. Verification is annual, by the Administration or RO, under regulations 6.9 and 37.3.
• Applying AR6 or GWP20 values. Regulation 2.3.2 and MEPC.391(81) use AR5 GWP100: 28 for CH4 and 265 for N2O.

Limitations

• Draft status. Every regulation number, date, threshold and price in this article comes from the text approved at MEPC 83 and published as MEPC/ES.2/2. None has legal force, and the text may change before adoption.
• Computed values. The well-to-wake intensities, the target values in gCO2eq/MJ, the energy shares and every tonne and dollar figure in the worked example are this site’s arithmetic on the draft and on MEPC.391(81) Appendix 2, rounded to one or three decimals or to the nearest 100 USD. They are not IMO figures.
• Assumed inputs. The 30.0 gCO2eq/MJ biofuel in the worked example is an illustrative assumption, not a default or a typical certified value.
• Default table. MEPC.391(81) Appendix 2 prints components, not totals, and leaves several pathways without a numeric well-to-tank value. The table is under review through the GESAMP LCA process, and a revision would move every attained GFI without any change to Chapter 5.
• Pending guidelines. The treatment of wind, solar, onboard carbon capture, partial years and ZNZ rewards depends on guidelines that have not been published.
• Units. The draft states balances and deficits in tonnes of CO2eq without writing the conversion from grams; this article divides by \( 10^{6} \).
• Timing. The 2028 first reporting year and the 2027 Registry and scheme deadlines are hard-coded in the draft on the assumption of entry into force in 2027.

Related Articles

• IMO Net-Zero Framework
• IMO Net-Zero Framework and GHG fuel intensity
• GFI reduction trajectory
• Base target annual GFI
• Direct compliance target annual GFI
• Surplus units under the IMO Net-Zero Framework
• Remedial units under the IMO Net-Zero Framework
• MEPC.391(81) LCA Guidelines
• Well-to-wake fuel pathways
• FuelEU Maritime explained
• MARPOL Annex VI
• Alternative marine fuels