FuelEU pooling (Article 21): rules, allocation and penalty

FuelEU Maritime sets its greenhouse-gas-intensity limit ship by ship: each vessel's attained well-to-wake intensity is compared with the year's target, and the difference, multiplied by the energy it used in scope, is its compliance balance. A fleet, though, rarely sits neatly on one side of the line — a ship on LNG or a biofuel blend runs a surplus while its sisters on fuel oil run deficits. Article 21 of the Regulation exists for exactly that fleet Reg (EU) 2023/1805 · Art. 21 ↗: it lets ships pool their balances so a surplus on one covers a deficit on another, provided the pool as a whole complies. This page is the deep-dive beneath the well-to-wake intensity guide: what a compliance balance is, the rules a pool must satisfy, how the allocation works in practice, and the penalty a valid pool turns into an internal transfer.

The compliance balance

Everything in pooling is arithmetic on one quantity. Annex IV Part A defines a ship's compliance balance for the reporting period as the gap between the year's target intensity and the ship's attained intensity Reg (EU) 2023/1805 · Art. 4 ↗, multiplied by the energy the ship used within the Regulation's scope Reg (EU) 2023/1805 · Annex IV Part A ↗.

CB = (GHGIE_target − GHGIE_attained) × E_{in scope}

GHGIE_target

the year's GHG-intensity limit (Art. 4(2)) [gCO₂e/MJ]

GHGIE_attained

the ship's attained well-to-wake GHG intensity [gCO₂e/MJ]

E_{in scope}

energy used in scope over the reporting period [MJ]

CB

compliance balance — positive = surplus, negative = deficit [gCO₂e]

A positive balance is a surplus; a negative balance is a deficit. Pooling moves balance between ships — it does not move intensity. After pooling, a deficit ship still attains the same intensity it attained before; only its balance for penalty purposes has changed.

The rules a pool must satisfy

Article 21 is short, and each sentence is a constraint the allocation has to respect Reg (EU) 2023/1805 · Art. 21 ↗:

• Same verifier. The balances pooled must be verified by the same verifier. Where the ships belong to different companies, the companies choose that verifier together and each of them validates the pool in the FuelEU database.
• One pool per ship per period. A ship's balance may not be included in more than one pool in the same reporting period.
• Validity, three tests. The pool is valid only if the total pooled compliance balance is positive; ships that had a deficit do not have a higher deficit after the allocation; and ships that had a surplus do not have a deficit after the allocation.
• Recorded, with a deadline. By 30 April of the verification period the chosen verifier records the definitive composition of the pool and the allocation of the total balance to each ship in the FuelEU database.
• Not alongside borrowing. Article 20 lets a ship bank a surplus for the next period or borrow a capped advance surplus against it Reg (EU) 2023/1805 · Art. 20 ↗, but a ship that borrows cannot pool in the same period, and borrowing cannot be used in two consecutive periods.

The Regulation fixes the constraints, not the allocation itself. Within those constraints the companies in the pool decide how the total is distributed, and the verifier checks that the result satisfies all three validity tests.

How the allocation works

One allocation satisfies every constraint by construction, and it is the one Carbonlogy's pooling engine applies: sum the balances; if the total is positive, bring every deficit ship exactly to zero, and leave the remainder with the surplus ships in proportion to what each contributed. A deficit ship can never end worse than it started, because it ends at zero; a surplus ship can never end in deficit, because the remainder it keeps is a share of a positive total. The engine refuses a pool whose total is not positive and reports why, so a fleet that is in deficit overall is never shown as compliant.

Penalty = |balance|attained × 41 000 × 2 400 €

balance

compliance balance (target − attained) × in-scope energy [gCO₂e]

attained

attained GHG intensity of the fleet's energy use [gCO₂e/MJ]

41 000

energy content of one tonne of VLSFO [MJ/t]

2 400

penalty per tonne of VLSFO-equivalent shortfall [EUR/t]

The Annex IV Part B penalty is what the deficit ships would otherwise pay Reg (EU) 2023/1805 · Annex IV Part B ↗: the deficit converted to tonnes of VLSFO-equivalent energy at the ship's own attained intensity, priced per tonne. Article 23 adds a multiplier for ships in deficit in consecutive periods Reg (EU) 2023/1805 · Art. 23 ↗, which a pool also avoids by keeping the ship's recorded balance at zero.

A worked scenario — not a regulator figure

No regulator publishes a pooling example, so the scenario below is Carbonlogy's own. The validity rules and the penalty basis are Article 21 and Annex IV, cited above; the ships, the balances and the resulting figures are hypothetical. The build-time verifier guarantees that the product's pooling engine reproduces every figure from the coefficient package each time this site is built; it does not, and cannot, make the figures a regulator's.

Worked scenario

A hypothetical three-ship pool (2025)

Worked scenarioCarbonlogy calculation, not a regulator figure · recomputed automatically · updated 2026-08-28

Hypothetical scenario — no regulator publishes a pooling example: three ships verified by the same verifier pool their compliance balances for one reporting period. Ship A ends the year in surplus; Ships B and C each carry a deficit that would otherwise be settled by the Annex IV penalty. Balances are in tonnes of CO₂-equivalent; each ship's attained intensity only prices its penalty and is unchanged by pooling.

Ship A — compliance balance

100 tCO₂e

Ship B — compliance balance

-40 tCO₂e

Ship C — compliance balance

-30 tCO₂e

Ship B — attained intensity

91 gCO₂e/MJ

Ship C — attained intensity

92 gCO₂e/MJ

Penalty per tonne of VLSFO-equivalent

2400 EUR

Energy of one tonne of VLSFO

41000 MJ

1. 1
   Pool validity (total > 0, no deficit worsened, no surplus into deficit)valid
2. 2
   Pooled compliance balance100 − 40 − 30 = 30 tCO₂e
3. 3
   Ship B after allocation (deficit covered to zero)0 tCO₂e
4. 4
   Ship C after allocation (deficit covered to zero)0 tCO₂e
5. 5
   Ship A after allocation (keeps the remainder)100 × 30 / 100 = 30 tCO₂e
6. 6
   Ship B — penalty if unpooled40 t / (91 × 41 000 MJ) × 2 400 € = 25730 EUR
7. 7
   Ship C — penalty if unpooled30 t / (92 × 41 000 MJ) × 2 400 € = 19088 EUR

Result · Penalty avoided by pooling44818 EUR

Last reviewed 28 August 2026 · Carbonlogy Compliance Team

How Carbonlogy applies it

Carbonlogy's FuelEU centre models pools directly. It lists every ship's verified compliance balance for the period, lets the operator assemble a candidate pool, and runs the allocation above: pool validity with the failing rule named if it fails, each ship's balance before and after, and the penalty avoided compared with each ship standing alone. Intensities are shown unchanged on both sides of the allocation, so no one mistakes a pooled balance for a cleaner ship.