This year, that line matters more than usual. The end of December closes the first UK ETS scheme year for maritime. It also closes the first EU ETS reporting year for which shipping companies will surrender allowances covering 100% of their eligible emissions, with methane and nitrous oxide now included alongside carbon dioxide.
It is also the final day before qualifying offshore ships of 5,000 GT and above enter the two schemes from January 2027. climate.ec.europa.eu
At sea, midnight on New Year’s Eve may pass without anything operationally significant changing. The same cargo remains onboard, the engines continue running, and the vessel proceeds towards the same destination.
On shore, that single voyage may now sit across two emissions-reporting years, two accounting periods and two sets of management reports.
The regulatory principle is clear. Under the EU Monitoring, Reporting and Verification framework, the reporting period runs from 1 January to 31 December. When a voyage crosses that boundary, the emissions generated up to 31 December belong to the first reporting year; those generated from 1 January belong to the next. climate.ec.europa.eu
Applying that principle consistently is where the real work begins.
Consider a tanker departing Rotterdam at 18:00 UTC on 27 December 2026 and arriving at Piraeus at 06:00 UTC on 8 January 2027.
Both ports are in the European Economic Area, so 100% of the voyage’s emissions fall within EU ETS.
Commercially, it is one voyage. The operator will want to assess its complete revenue, fuel consumption, port costs, delays and final contribution as one result. The master and chief engineer are managing one passage, while the charter party does not acquire a convenient dividing line simply because the year changes.
For emissions reporting, the year-end boundary divides it into two periods.
| Simplified example | Whole voyage | 2026 portion | 2027 portion |
|---|---|---|---|
| Time at sea | 11.5 days | 4.25 days | 7.25 days |
| Fuel consumed | 345 t | 127.5 t | 217.5 t |
| CO₂ emitted | 1,074 t | 397 t | 677 t |
| EU ETS scope | 100% | 100% | 100% |
Simplified illustrative example, assuming constant consumption of 30 tonnes per day and an emission factor of 3.114 tonnes of CO₂ per tonne of the selected fuel. This is not intended as a compliance calculation.
The business needs two legitimate views of the same activity: the complete voyage for commercial and operational analysis, and a time-based allocation for emissions and financial reporting.
Neither view is wrong. The challenge is producing both from the same underlying voyage without duplicating, omitting or inconsistently allocating its data. That is manageable when there is one controlled voyage record. It becomes a reconciliation exercise when commercial, compliance and finance each work from their own copy.
The year-end boundary sounds precise, but the vessel’s local time may be several hours ahead of or behind UTC.
EU maritime reporting records voyage departure and arrival times using GMT/UTC. The relevant boundary is therefore 00:00 UTC on 1 January, rather than the moment the vessel’s clocks reach midnight. eur-lex.europa.eu
Noon reports are unlikely to fall exactly on that boundary. The company therefore needs an agreed and defensible method for establishing consumption at 00:00 UTC, consistent with its approved monitoring plan and the equipment available onboard.
That information may come from an appropriately timed measurement, continuous monitoring or a documented calculation. Whichever method is used, it should be understood before the vessel reaches year-end—not reconstructed several weeks later while different departments compare their totals.
For the Rotterdam-to-Piraeus example, both portions of the voyage are fully within EU ETS scope. An allocation error could move emissions between reporting years without changing the overall quantity eventually covered.
For offshore vessels entering the scheme, the boundary has a more immediate financial effect.
Offshore ships of 5,000 GT and above enter EU ETS from the 2027 reporting period. Qualifying offshore ships also enter UK ETS from January 2027. For an offshore construction or support vessel working through New Year, December activity may fall outside the relevant trading scheme while eligible January activity falls inside it.
An inaccurate split could therefore produce an incorrect allowance requirement, rather than simply placing the correct emissions in the wrong annual report.
The situation still depends on the vessel, activity, route and applicable exemptions. “Offshore” should not be treated as a sufficient classification on its own.
A year-spanning voyage does not belong to one department.
The commercial operator wants to know whether the complete voyage performed as expected. Did additional steaming time, weather, port delays or bunker consumption change the result? How does the final performance compare with the estimate?
The emissions or compliance team needs a defensible record of the fuel consumed and greenhouse gases emitted in each reporting year. That record now carries greater financial weight: EU ETS reaches 100% of eligible reported emissions for 2026, while methane and nitrous oxide have entered the scheme alongside carbon dioxide.
Finance needs the correct carbon exposure represented in the appropriate period. Under EU ETS, the formal obligation sits with the responsible shipping company—either the registered owner or an ISM company that has formally assumed the relevant responsibilities. The commercial cost may then be allocated between the parties through contractual arrangements, including clauses developed by BIMCO.
The vessel supplies much of the operational evidence through fuel measurements, noon reports, port activity and records of consumption.
Senior management may ask a simpler-sounding question: what is our total exposure at year-end?
Every person can perform their part correctly and still produce a different answer if they are working from separate versions of the voyage.
A voyage may have been estimated in December, updated as conditions changed, and completed in January. Its final consumption figures may not be available until after arrival. A corrected vessel report, revised port time, or bunker adjustment can alter the allocation after an initial year-end figure has already been circulated.
Several familiar problems can follow.
If annual reports select voyages using their departure or arrival dates, rather than allocating activity across the reporting boundary, the complete voyage may be pulled into one report and then appear again in another.
The totals can still look credible because the voyage itself is genuine. The duplication may only become apparent when someone reconciles the annual figure against vessel consumption or allowance exposure.
The opposite problem occurs when the system assigns the entire voyage according to a single date. A December departure may push all its emissions into the earlier year, while a January arrival may move everything into the later one.
That preserves the voyage as a single record, but it does not meet the EU MRV requirement to account for each portion within its respective reporting period.
Commercial teams may update the completed voyage while the emissions team continues working from an earlier spreadsheet export.
Both versions can have a clear history and a responsible owner, yet no longer describe precisely the same operation. When the difference is discovered, the discussion moves away from emissions performance and towards establishing which extract was used, when it was taken and whether later amendments were included.
A voyage that remains underway at year-end will contain information at different levels of certainty. Consumption already recorded can be supported by vessel data, while the remainder of the voyage is still being forecast.
A management estimate can legitimately include projected emissions. The problem arises when provisional information loses its status and quietly becomes the apparent final result.
Maritime entered the UK ETS on 1 July 2026, so its first scheme year covers only the period from 1 July to 31 December. From 2027, scheme years run from 1 January to 31 December.
The current maritime scheme generally covers cargo and passenger ships of 5,000 GT and above on domestic UK voyages, together with emissions from their activity in UK ports. Relevant exemptions and route-specific provisions also apply. www.gov.uk
This December will therefore be the first time maritime operators divide an eligible voyage between two UK ETS scheme years. The legislation confirms that when a voyage begins in one scheme year and finishes in another, its emissions must be accounted for in the respective years in which they occur. www.legislation.gov.uk
A domestic voyage leaving Felixstowe on 30 December and arriving in Aberdeen after New Year must be preserved as one operational voyage while its emissions are divided between the two reporting periods.
The interaction between regimes also becomes visible on international routes. A vessel sailing from Felixstowe to Rotterdam has its eligible activity in the UK port covered by UK ETS, while 50% of the emissions from the international voyage fall within EU ETS because it arrives in the EEA from a port outside it.
These calculations should not be compressed into one undifferentiated carbon figure. Teams need to see which regime applies, which activity is in scope, what proportion is relevant and which reporting period receives the emissions—without losing the complete voyage required for commercial review.
Port classification, voyage dates, time zones, fuel type, consumption adjustments and the distinction between in-port and sailing activity can all affect the result.
UK reporting and surrender deadlines are confirmed in the Government’s maritime guidance. www.gov.uk
A useful year-end review should go beyond checking whether an annual total has been produced.
Confirm that teams understand the reporting cut-off and that the method used to establish consumption at the boundary is consistent with the company’s monitoring plan.
Consumption and emissions should be allocated to their respective periods, rather than duplicated or assigned wholesale according to the voyage’s departure or arrival date.
Splitting emissions for regulatory reporting should not damage the commercial record. Operators should still be able to review the complete estimate, actual result and voyage contribution.
Anyone reviewing the figures should be able to see what has been reported, what remains estimated and what changed after the original calculation.
If consumption, dates, or port activity change, the effect should reach the emissions calculation, voyage result, and relevant reports. A correction entered once should not create three separate reconciliation exercises.
A figure is easier to trust when the user can trace it back to the voyage, vessel reports, fuel consumption, and reporting rule behind it. That matters to internal reviewers as much as it does to external verifiers.
The annual emissions report may be the formal output, but its reliability depends on information recorded throughout the year.
Port records must be accurate. Vessel activity needs to arrive consistently. Fuel consumption, bunkering and debunkering must be reflected correctly. Changes to a voyage need to remain connected to the commercial and accounting records that depend on them.
When that information is assembled only as a deadline approaches, experienced people become the integration layer. Their time is spent comparing voyage lists, finding missing activity and establishing which version of a record is current.
Their judgement remains essential. Repeatedly rebuilding the history of a voyage should not be.
A connected system cannot remove the year-end boundary. It can make that boundary easier to manage.
The voyage should remain a recognisable commercial operation while the relevant consumption and emissions are allocated accurately across each reporting period. Corrections should retain their relationship to the original activity, and users should be able to move from an annual figure back to the voyages and operational records behind it.
Shipnet’s EU ETS and UK ETS capabilities support year-spanning voyages across reporting periods without double counting. Working from connected voyage estimation and accounting information gives teams the regulatory view they need without losing sight of the commercial voyage.
The practical test comes when finance, operations, and compliance meet to review the year-end position. Are they discussing the performance—or spending the meeting establishing whose total is correct?
If the answer depends on a spreadsheet, a manual adjustment, or one colleague who remembers how the figures were assembled, the process deserves attention before 31 December.
The vessel will continue sailing through midnight. The information supporting it should make the transition just as cleanly.
Danny James
Marketing Manager