What data do you need for vessel emissions reporting?
Vessel emissions reporting rests mainly on EU MRV, which covers ships of 5,000 gross tonnage (GT) and above on voyages to or from European Economic Area (EEA) ports, plus FuelEU Maritime and MARPOL Annex VI sulphur limits. Collect fuel, distance, time at sea and cargo, convert fuel to gas figures, and have a verifier check the report.
Which regulations apply, and to which ships?
The EU MRV Maritime Regulation applies to ships of 5,000 GT and above for greenhouse gas emissions released on voyages from and/or to ports in the EEA, when they carry cargo or passengers commercially. The EU ETS company-level report and FuelEU Maritime draw on the same voyage data. MARPOL Annex VI works differently: it sets limits on fuel and emissions rather than asking for an annual emissions report.
The scope has widened. From 1 January 2025, general cargo ships between 400 and 5,000 GT, and offshore ships of 400 GT and above, fell under the amended MRV Regulation. Since 1 January 2024, companies must report methane (CH4) and nitrous oxide (N2O) as well as CO2.
| Regime | Scope | Gases or pollutants | Deadline | Who checks |
|---|---|---|---|---|
| EU MRV | Ships of 5,000 GT and above, plus smaller cargo and offshore ships from 400 GT since 2025 | CO2, plus CH4 and N2O since 2024 | 31 March each year from 2025 | Accredited independent verifier |
| EU ETS company-level report | Ships within the ETS Directive | Aggregated in tonnes of CO2 equivalent, by gas | 31 March each year from 2025 | Accredited verifier |
| FuelEU Maritime | EU port arrivals and departures | All greenhouse gases, well-to-tank and tank-to-wake | 31 January 2026 to the verifier, for 2025 data | Independent verifier |
| MARPOL Annex VI sulphur | Fuel oil used by ships | Sulphur: 0.50% globally, 0.10% in ECAs | No annual report | Port State and flag State |
What data must a vessel collect?
Capture fuel consumed at sea and at berth, distance travelled, time spent at sea and cargo carried. The EU's MRV description lists energy efficiency, distance travelled, time at sea and cargo carried alongside the emissions themselves. Emissions released at berth in an EEA port of call are covered, and companies must report them annually as a separate item.
FuelEU adds requirements. For each EU port arrival and departure, you record fuel consumption at berth and at sea, the amount of electricity received through shore power, and well-to-tank and tank-to-wake emission factors for each fuel type.
Where does the data come from?
On a ship without automated collection, noon reports are usually enough for voyage totals and fuel trends. Reconcile them with bunker records, and record a missing value as a gap. If you interpolate, label it, because a verifier may ask which numbers were measured. If you automate collection from engine and flow sensors, the protocol matters; see NMEA 2000 vs Modbus vs OPC UA for what each does on a vessel.
How does fuel become CO2, CH4 and N2O figures?
Multiply the mass of each fuel burned by a fuel-specific emission factor for each gas, then add the results. The company-level report expresses totals in tonnes of CO2 equivalent and disaggregates them by individual greenhouse gas. Your monitoring plan fixes which method and factors you apply, so use those rather than a fresh choice each year.
What is the reporting cycle?
The cycle runs in four steps:
- Draft a monitoring plan for each ship. Companies draft it in THETIS-MRV from a template in an Implementing Regulation, and an independent accredited verifier assesses it.
- Monitor emissions through the calendar year, following that plan.
- Produce the emissions report for the whole reporting period and have a verifier check it.
- Submit through THETIS-MRV.
Which year does a voyage belong to?
A reporting period runs from 1 January to 31 December. For voyages starting and ending in two different calendar years, you account the data under each reporting period. So split the fuel and distance at the year boundary, and keep berth fuel separate from at-sea fuel for each port call.
What are the deadlines?
For FuelEU, the reporting period is the year monitored, and the verification period is the year after. The first report submission to a verifier is due on 31 January 2026, with data from 1 January to 31 December 2025.
For MRV, from 2025 companies submit a verified emissions report by 31 March of each year for the previous year. Under ETS, verification is due by 31 March, or by 28 February if the administering authority requests it. Work back from the earliest date: close the year's voyage dataset in January, and the same data then serves FuelEU, MRV and ETS.
Who verifies and submits the report?
The shipping company submits, and an independent accredited verifier assesses the monitoring plan and the report. Under MRV, the report goes through THETIS-MRV to the administering authority, the flag State authorities if the ship flies an EEA flag, and the European Commission. The verifier must find the report satisfactory before submission. Expect the verifier to test your records against the plan, so bunker notes, voyage logs and gap labels need to agree.
How are NOx, SOx and other pollutants handled under MARPOL Annex VI?
Annex VI controls air pollutants through limits, and the fuel you use shows compliance, not an annual emissions report. The global sulphur cap fell from 3.50% to 0.50% m/m on 1 January 2020. In emission control areas, fuel oil cannot exceed 0.10% sulphur (1,000 ppm), including the North American and US Caribbean Sea ECAs. In the North American ECA, operators must use compliant fuel within 200 nautical miles of the coast.
Keep bunker delivery records and fuel changeover logs to show compliance.
How do you keep one dataset behind every report?
Build one voyage and fuel dataset and let each report draw from it. When fuel records sit in noon reports, bunker files and engine telemetry, each new deadline means re-assembling them by hand. A unified schema removes that rework by putting a fleet's records into one structure that any authorized tool can query. Engine-room knowledge matters too; see searchable technician knowledge. If you want to see how a unified schema could be built from your own systems, start with a demo.
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