Frequently Asked Questions

FuelEU Maritime (Regulation EU 2023/1805) is an EU regulation that sets progressively tighter limits on the greenhouse gas intensity of energy used on board ships. It applies to all vessels above 5,000 gross tonnage that carry cargo or passengers for commercial purposes and call at EU ports - regardless of the ship's flag state. The regulation came into force on 1st January 2025 and covers 100% of energy used on voyages between EU ports and in EU ports at berth, and 50% of energy on voyages where only one port is within the EU.

FuelEU Maritime measures compliance through a ship's yearly average GHG intensity: the amount of greenhouse gas emissions (CO₂, methane, and nitrous oxide) produced per megajoule of energy used on board, calculated on a well-to-wake basis. Well-to-wake means the full lifecycle of the fuel is counted - from production and transport through to combustion - not just what comes out of the exhaust. Each ship's actual GHG intensity is compared against a target that tightens over time, starting with a 2% reduction from the 2020 reference value in 2025 and stepping up to an 80% reduction by 2050. The difference between a ship's actual and target intensity produces a compliance surplus or deficit, which determines whether penalties, flexibility mechanisms, or both come into play.

If a ship ends the compliance year with a deficit - meaning its GHG intensity exceeded the allowed limit - it faces a financial penalty set at €2,400 per tonne of VLSFO equivalent of non-compliant energy use. In practice, the penalty is calculated by dividing the absolute compliance deficit by the ship's actual GHG intensity and multiplying by €2,400. Penalties also increase for consecutive years of non-compliance. Because the penalty is designed to be more expensive than the cost of using cleaner fuels or compliance mechanisms, paying it is rarely the optimal choice - but it is the default outcome for operators who take no action.

FuelEU Maritime provides three built-in mechanisms for managing compliance. Banking lets an overcompliant ship carry its surplus forward to future years - banked compliance never expires. 

Borrowing lets an undercompliant ship draw up to 2% of next year's compliance in advance, though a 10% premium is charged the following year and borrowing cannot happen two years in a row. 

Pooling is the most commercially significant option: it allows vessels from different owners and verifiers to combine their compliance balances, so surpluses from ships with lower emissions offset deficits in others - with no changes required to how the deficit vessels operate. The pool's total balance must be positive, and all allocations are verified and registered in the Thetis EU database by 30 April each year.

These are three separate but overlapping regulatory frameworks, each targeting a different aspect of maritime emissions. FuelEU Maritime sets limits on the full lifecycle GHG intensity of fuel used on board and applies a penalty per unit of non-compliant energy - its primary lever is fuel quality and compliance flexibility mechanisms like pooling.

EU ETS (Emissions Trading System) requires shipping companies to surrender carbon allowances for each tonne of CO₂ emitted, with coverage phasing up to 100% by 2026 - it is a carbon pricing mechanism, not a fuel standard. 

CII (Carbon Intensity Indicator), set by the IMO, rates each ship's operational carbon efficiency annually from level A to E, and triggers corrective action plans for poor performers - it focuses on voyage efficiency rather than fuel composition. A vessel calling EU ports will need to manage all three regulations simultaneously, though the costs and compliance actions for each are distinct.

The Document of Compliance (DOC) holder is the company legally responsible for a vessel's operation under the ISM Code - typically the shipowner, technical manager, or charterer registered as the operating entity. Under FuelEU Maritime, the DOC holder is the party accountable for monitoring and reporting the ship's fuel consumption, submitting data for verification, registering in the FuelEU database (Thetis), and ultimately holding the FuelEU Document of Compliance that proves the vessel has met its annual obligations. 

In a pooling arrangement, it is the DOC holder who registers a vessel in a pool in Thetis and allocates compliance balance in a pool - making their cooperation essential for any pooling service to function in practice. If a vessel changes DOC holder mid-year, compliance responsibility is split according to the period each party held operational control.

Compared to paying the penalties, pooling is a more economically feasible option. Ultimately, the decision to pool or pay penalties depends on the vessel’s verified compliance balance, the availability/cost of pooling counterparties, and the company’s risk and cost strategy. FuelEU explicitly allows several compliance paths - including pooling as a flexibility mechanism - and penalties apply when compliance is not achieved through operational measures or flexibility mechanisms.

The core advantage is that pooling lets ships with a compliance surplus offset deficits in others, turning over-performance on one vessel into a financial asset rather than a sunk cost. For the deficit side, pooled compliance consistently comes in below both the €2,400/tonne-VLSFO equivalent penalty rate and the cost of blending biofuels - making it the most cost-efficient path for operators who aren't switching fuels or retrofitting. It also replaces an unpredictable year-end liability with a contracted price agreed in advance, which makes budgeting considerably easier than waiting to discover a penalty exposure after the compliance year closes.

All three are legitimate flexibility mechanisms, but they serve different situations. Banking and borrowing operate at the level of a single vessel - a surplus is saved for future years, or next year's compliance is drawn forward at a 10% premium - and neither can be used to transfer compliance between vessels. Pooling works differently: it combines the compliance balances of multiple vessels across different owners and verifiers, letting surpluses from ships cover deficits in others, with no changes to how those vessels operate. For most fleet operators with a compliance deficit, pooling is the more cost-effective and lower-risk path - borrowing defers the problem with interest, while pooling resolves it.

Yes, combining mechanisms is possible. A vessel can participate in a compliance pool and still bank any remaining surplus for future years. What the regulation does not allow is placing a single vessel in more than one pool simultaneously, or borrowing while participating in a pool. A common combination is joining a third-party pool like Ahti's to cover a deficit, while banking surplus from overcompliant vessels within the same fleet for use in later years when the GHG intensity targets tighten further.

The main advantage of pooling over penalties is timing and distribution. Penalties are always settled after the compliance year closes - in a single payment, once the verified balance is confirmed. With pooling, compliance costs can be spread across the year as compliance units are transferred, aligning expenditure with operations rather than creating a concentrated year-end liability. Operators who prefer cost certainty upfront can also agree a fixed volume of compliance balance with Ahti in advance, with payment terms structured accordingly.

FuelEU Maritime pooling is a voluntary compliance mechanism that allows two or more vessels - across different owners and verifiers - to combine their compliance balances, so that surpluses from cleaner ships offset deficits in others. In practice, participating companies register their vessels in the Thetis EU database, agree on how the combined compliance balance is allocated across the pool, and have the allocation verified by an accredited verifier before the 30th April deadline. The pool is valid as long as its total balance remains positive, meaning no individual deficit can drag the group out of compliance. Unlike EU ETS, there is no open market for pooled compliance - it is arranged through bilateral or managed agreements, which is where a third-party pool manager like Ahti comes in.

Any commercial vessel above 5,000 gross tonnage that falls within the scope of FuelEU Maritime can participate in a pool - regardless of flag state, ownership structure, or which accredited verifier the company uses. The one exception is vessels that have not received a Document of Compliance for the previous reporting period, for example due to an unpaid penalty - these vessels are ineligible to join a pool until their compliance record is cleared.

Most importantly, vessels from entirely different companies can pool together, meaning you do not need to be part of the same fleet or corporate group. The hard constraint here is that a vessel can only belong to one pool per compliance year. In practice, the easiest vessels to pool are those on own-voyage operations or voyage charters out - long-term time-chartered vessels can be pooled but require the compliance responsibility to be clearly agreed in the charter contract first.

The practical risks in pooling are operational rather than regulatory - incorrect assumptions about a vessel's verified compliance balance, late registration in the Thetis database, counterparty performance, or an allocation that leaves some ships still in deficit after the pool is settled. The regulation builds in several hard constraints to contain these risks: a vessel can only belong to one pool per year, the total pool balance must be positive, no deficit ship can deepen its deficit through pooling, and no surplus ship can be pushed into deficit by the allocation. 

All of this is validated by an accredited verifier and recorded in the FuelEU database, making outcomes fully auditable. The commercial terms - pricing, volumes, allocation rules - sit outside the regulation and are agreed contractually between participants, which is why the quality of the pool manager and the robustness of the contract framework matter as much as the compliance mechanics themselves.

Compliance responsibility follows the DOC holder. When a vessel changes hands mid-year, reporting responsibility is split: the outgoing company covers the period it operated the vessel, and the incoming company takes over from the date of transfer. Financially, however, the picture is different - the company holding DOC status on 31 December carries full responsibility for the compliance outcome for the entire reporting year. This is why compliance exposure is almost always addressed explicitly in sale and purchase terms, and why timing matters.

For vessels in the Ahti pool, continuing in the pool is one option available to the new owner - subject to Ahti's standard onboarding and KYC requirements. Since a vessel can only belong to one pool per compliance year, that decision needs to be made promptly after the transfer. If the new owner opts out, their compliance outcome is assessed on the vessel's verified standalone balance, and the usual options - pooling elsewhere, banking, borrowing, or paying the penalty - remain available.

Thetis EU is the European Maritime Safety Agency's official database where all FuelEU compliance actions are recorded. Pool registration follows a defined sequence: first, each participating company registers its intention to pool in Thetis and selects a verifier to oversee the pool's compliance allocation. One company then acts as the pool organiser, creating the pool in the database and proposing how the total compliance balance is distributed across member vessels. All participating companies must then validate the allocation in Thetis before the 30 April deadline. Once validated, the selected verifier reviews and records the final pool composition and allocation - after which the FuelEU Document of Compliance can be issued to each vessel by 30 June. The entire process is auditable and transparent, with every step timestamped in the database.

No - this is one of the regulation's hard rules. A vessel's compliance balance can only be included in one pool per reporting year, regardless of ownership changes or chartering arrangements during that period. This makes the choice of pool - and pool manager - a consequential one, since there is no switching mid-year if the arrangement doesn't work out. It also means that operators managing multiple vessels need to think carefully about whether to place all vessels in the same pool or structure internal sub-pools alongside a third-party arrangement, depending on how their compliance balances interact.

Ahti operates as an all-inclusive third-party pool manager, covering the compliance, contractual, and administrative workflow that pooling requires throughout the full compliance year. Concretely, this means Ahti assesses each vessel's compliance position before joining, secures sufficient compliance units from the pool's surplus producer vessels, and transfers validated compliance units to member vessels throughout the year - spreading compliance costs rather than settling them in a single year-end transaction. 

For operators who prefer certainty upfront, Ahti can also accommodate a fixed volume of compliance balance transferred in one transaction at an agreed price.

Pool members retain responsibility for registering their own vessels in Thetis and coordinating with their own verifier; Ahti manages the pool balance, carbon balance bookkeeping, reporting, and validation of pool transactions on their behalf.

Members also get access to the Ahti Calculator for ongoing compliance scenario planning and fuel mix optimisation, and Ahti proactively rebalances the pool throughout the year to ensure the total compliance balance stays positive.

Pooling introduces risks beyond the compliance balance itself - price volatility, counterparty exposure, contractual allocation uncertainty, and the administrative burden of verification and reporting, all of which fall on the DOC holder. Poorly managed pooling arrangements can affect fuel procurement strategy, charter competitiveness, and vessel resale value as much as non-compliance itself.

Ahti addresses this through pre-agreed, transparent pricing that eliminates possible end-of-year compliance unit price hike, active pool balance management throughout the compliance year, and a structured contractual framework with uniform pool rules applied consistently to all members. All pool participants go through rigorous onboarding covering creditworthiness, sanctions screening, and ownership transparency before being admitted. The result is that compliance doesn't just get settled - it gets managed as a controlled, predictable part of fleet operations.

The process has four clear steps. It starts with an initial compliance assessment - you indicate your fleet's compliance need, and Ahti helps quantify this based on fuel consumption data if needed, so both sides have a clear picture before any commitment is made. Ahti then runs a KYC check which all pool members go through as a condition of joining. Once that clears, Ahti sends the Accession Agreement and Pool Rules for review and signing - that's the point at which your vessels formally become pool members. Onboarding then begins, with Ahti setting up the necessary data connections and supporting you through the Thetis EU registration and verifier alignment steps that the regulation requires on your side.

The full process is designed to be completed well before the compliance year closes - and the earlier it starts, the better the compliance unit pricing available to you.

Yes, there is no minimum fleet size requirement for joining the Ahti pool. The pay-as-you-go pricing model and flat annual admin fee per vessel mean that the cost structure scales with the size of your operation rather than assuming a large fleet. Fixed-volume one-off purchases are also possible. 

For single-vessel operators in particular, joining a third-party pool like Ahti's is often the most practical path to compliance, since an internal pool requires at least two vessels and a bilateral arrangement to be worth the contractual overhead.

Ahti's pricing has two components. The first is an annual admin fee per vessel, which covers part of the verification cost, data integration with your classification society, and access to the Ahti Pooling Platform. The second is a per-unit compliance price based on your fleet's actual deficit.

On the compliance side, operators can purchase units on a pay-as-you-go basis as they are transferred throughout the year, or commit to a fixed volume upfront at an agreed price - with payment terms structured accordingly.

FuelEU operates on an annual reporting cycle, with the compliance year running on the calendar year and the verification period taking place in the first half of the following year.

The key deadlines are:

31 January - Ship operators submit their annual FuelEU emission report to their verifier

31 March - The verifier validates and registers verified compliance balances in the Thetis EU database

30 April - Operators report their use of flexibility mechanisms - pooling, banking, or borrowing - and pool allocations are finalised in Thetis

30 June - Documents of Compliance are issued; any outstanding penalties must be paid.

Pool allocations must be finalised and approved by all pool members in the Thetis EU database by 30 April, following the close of the compliance year. The verified compliance balances that form the basis of the pool are registered by verifiers by 31 March, which is when the 30-day window for pool finalisation effectively opens. Missing the 30 April deadline means losing the ability to use pooling as a flexibility mechanism for that reporting year entirely - leaving penalties as the only remaining option.

The regulation allows pooling to be arranged at any point during the compliance year, but waiting until the April deadline is a costly strategy. Compliance unit prices rise as awareness and demand grow through the year, and year-end supply is uncertain - operators who secure pooling contracts early lock in better pricing and eliminate the supply risk entirely. There is also a practical lead time to account for: KYC checks, contract signing, and data integration all take time, and starting in Q4 of the compliance year leaves little room for delays. The straightforward answer is that the best time to arrange pooling for a given compliance year is before it begins, or as early in the year as possible.

Missing the 30 April pooling deadline means forfeiting the option to use pooling for that reporting year - the only remaining paths are banking, borrowing, or paying the penalty. Missing the 30 June penalty payment deadline and not having a valid DoC has more than just financial impacts.  The vessel could be refused entry to EU ports until the compliance record is cleared. Beyond the direct financial and operational impact, a non-compliance record can affect a vessel's charter rate and resale value, since counterparties increasingly factor regulatory standing into commercial negotiations.