Greenhouse gas rules bring fuel use and port calls into the same planning discussion. For chemical tankers, the first distinction is between IMO's draft global Net-Zero Framework and the European Union's measures already applying to shipping. The EU Emissions Trading System (EU ETS) addresses emissions through allowances; FuelEU Maritime sets limits on the greenhouse gas intensity of onboard energy. Understanding their different purposes helps keep voyage assumptions clear.
Two Layers of Rules
IMO's framework is designed around international regulations, while the EU measures have a regional scope tied to port calls and voyages. A ship's flag alone does not settle its position under the EU rules: both the EU ETS shipping coverage and FuelEU Maritime apply regardless of flag within their respective scope. Equally, an EU requirement should not be described as a worldwide rule.
It helps to ask separate questions. Has a measure been adopted, or is it still a proposal? Which ships and routes does it cover? Does it concern the emissions themselves or the intensity of the energy used? These questions prevent a headline about one measure from becoming an assumption about all of them.
The IMO Net-Zero Framework
IMO approved the Net-Zero Framework at the Marine Environment Protection Committee's MEPC 83 session in April 2025. It was included as Chapter 5 of the draft revised MARPOL Annex VI, in line with IMO's 2023 greenhouse gas strategy. Its paired elements are a global fuel standard and a global greenhouse gas emissions pricing mechanism.
Approval of that draft did not complete adoption. In its 17 October 2025 account of the extraordinary MEPC session, IMO said discussions on adoption had been adjourned for one year. The session had met from 14 to 17 October 2025. IMO also said the intersessional greenhouse gas working group scheduled for 20 to 24 October would continue work on implementation guidelines.
The framework therefore remains an approved draft awaiting adoption, rather than a rule in force. Work on guidelines and agreement on draft text are stages in that process; neither should be treated as an operating deadline. For planning purposes, the distinction is between following a proposed global approach and meeting obligations under measures already applying.
The EU Emissions Trading System at Sea
The European Commission's EU ETS shipping guidance says coverage began in January 2024 for CO2 emissions from ships of 5,000 gross tonnage and above entering EU ports, regardless of flag. Coverage is 50% of emissions from voyages starting or ending outside the EU, and 100% of emissions between EU ports and within EU ports. Methane and nitrous oxide are included from 2026.
An itinerary that links an EU port with a port outside the EU belongs to a different coverage category from a voyage between EU ports. The port sequence therefore helps explain why otherwise similar voyage descriptions can carry different emissions accounting assumptions. Ship nationality does not replace that route-based distinction.
Route coverage and the allowance surrender phase-in describe different things. The route percentages identify the share of emissions within the system's scope. The phase-in describes the portion of reported emissions for which allowances must be surrendered in the relevant year. Keeping those ideas separate makes the schedule easier to read.
Allowances surrendered in 2025 cover 40% of reported 2024 emissions. In 2026 the share is 70% of reported 2025 emissions; from 2027 onwards it is 100% of reported emissions. The first surrender deadline was September 2025, relating to emissions reported for the 2024 calendar year.
That separation matters when comparing voyage costs across years. A note labelled only with a surrender year leaves out the emissions period behind it. A clearer comparison records the voyage's EU coverage alongside the emissions year, covered gases and applicable surrender stage, rather than treating the phase-in percentage as a change in the route's geographic scope.
FuelEU Maritime
FuelEU Maritime, Regulation (EU) 2023/1805, has applied in full since 1 January 2025; its monitoring-plan provisions in Articles 8 and 9 applied from August 2024. It sets maximum limits on yearly average greenhouse gas intensity of energy used by ships above 5,000 gross tonnage calling at EU ports, regardless of flag.
The reduction targets begin at 2% by 2025 and reach 80% by 2050. They cover carbon dioxide, methane and nitrous oxide over the full lifecycle of fuels, described as a well-to-wake basis. This makes the energy's lifecycle greenhouse gas intensity central to the measure, rather than simply the quantity of fuel carried.
For FuelEU, the yearly average is the key planning timescale. A single voyage description does not by itself describe the ship's annual energy mix. Comparing an individual sailing with an annual intensity target requires that distinction to be explicit.
The Commission also records delayed application in Norway and Iceland while incorporation into the EEA Agreement is pending. Its guidance treats Norwegian and Icelandic ports as third-country ports for FuelEU from 1 January 2025 until that incorporation. Port geography alone should therefore not be used to assume the same FuelEU treatment everywhere in Europe.
What It Means for Voyage Planning
A practical comparison starts with the itinerary and the energy assumptions. Identify which port calls and voyage legs fall within EU ETS coverage, then keep the allowance surrender timetable alongside the emissions year. Consider FuelEU separately as a yearly average energy-intensity measure. The different thresholds also deserve care: EU ETS guidance says 5,000 gross tonnage and above, while FuelEU says above 5,000.
Neither a phased allowance surrender share nor a FuelEU intensity reduction target is a statement of how much a particular voyage's total freight cost will change. They answer different regulatory questions. A cost estimate needs its route, fuel and timing assumptions to remain visible rather than presenting any of these percentages as a general freight surcharge.
Fuel choice and EU port calls consequently carry a cost and compliance dimension alongside the voyage itself. Keeping each measure's scope, timing and purpose explicit supports a more useful comparison than a single undifferentiated carbon-cost label.