Two separate carbon frameworks in European freight
The European Union operates two distinct climate mechanisms that affect ocean freight: the Maritime Emissions Trading System (EU ETS Maritime) and the Carbon Border Adjustment Mechanism (CBAM). Because both systems deal with carbon and international supply chains, importers and freight forwarders frequently confuse them. They address entirely different scopes of activity.
EU ETS Maritime regulates the propulsion emissions of commercial ships travelling to, from, or between European ports. Shipping lines must purchase and surrender European Union Allowances (EUAs) for the bunker fuel burned during sea voyages. Ocean carriers pass this compliance cost to cargo owners as an ETS surcharge per container.
In contrast, CBAM regulates the greenhouse gases emitted during the industrial manufacture of carbon-intensive goods overseas, including iron, steel, aluminium, cement, fertilisers, and hydrogen. Importers must declare these embedded production emissions under specific 8-digit Combined Nomenclature (CN) codes and purchase CBAM certificates.
Freight surcharges are not CBAM tax payments
An EU ETS surcharge on an ocean freight bill covers vessel bunker fuel emissions. It does not satisfy your CBAM import obligations, nor does it count toward CBAM certificate purchases. Freight transport emissions are not included in CBAM product declarations.
How container carbon footprints are calculated
To manage carbon costs and prepare transport emissions disclosures, you need to understand how an individual container shipment receives an emissions value. The Global Logistics Emissions Council (GLEC) Framework provides practical guidance aligned with ISO 14083:2023, the international standard for quantifying and reporting transport chain emissions.
For a tonne-kilometre estimate, multiply net cargo mass in tonnes by sea distance in kilometres and a matching emission intensity in grams of CO2e per tonne-kilometre. The result is grams of carbon dioxide equivalent (CO2e); divide by 1,000 to express it in kilograms. Keep the mass, distance and emissions boundary consistent with the chosen factor:
- Sea distance: Use the sea route between the port of loading and port of discharge, including relevant feeder legs. Convert nautical miles to kilometres before applying a tonne-kilometre factor. Follow the chosen methodology's distance adjustment rules when actual route data is unavailable.
- Net cargo mass: Use the mass of the goods, excluding the container's tare weight, for cargo tonne-kilometres. Follow the GLEC Framework's transport activity guidance. Do not add tare to a factor expressed per net cargo tonne-kilometre.
- Emission intensity factor: The grams of CO2e emitted per tonne-kilometre (g CO2e/t-km). This factor varies dramatically based on vessel class, nominal capacity, fuel type, and lane utilisation.
Vessel size alone does not determine a shipment's emission intensity. Fuel, speed, utilisation and the trade lane also matter. Use a documented carrier or lane factor where available, and calculate feeder legs separately when their factors differ. Do not treat one vessel-size estimate as a universal value for every sailing.
Calculations must also distinguish between Tank-to-Wake (TTW) and Well-to-Wake (WTW) boundaries. Tank-to-Wake measures direct exhaust emissions generated while the vessel burns fuel at sea. Well-to-Wake encompasses the complete lifecycle footprint, including fuel extraction, refining, transport, and bunkering. International reporting standards, including GLEC and ISO 14083, require Well-to-Wake accounting for carbon disclosures.
How EU ETS Maritime works in 2026
The maritime sector entered the EU ETS in January 2024 with a multi-year phase-in. The European Commission's shipping emissions guidance explains that the surrender requirement covers 40% of in-scope emissions for 2024, 70% for 2025 and 100% for 2026 onwards. The voyage coverage percentages below still apply; the phase-in does not make an international voyage's entire footprint liable.
- Intra-EU voyages (100% liability): Any voyage starting and ending at ports within the EU and European Economic Area (EEA), as well as emissions generated at berth in EU ports, faces 100% allowance surrender requirements.
- International voyages (50% liability): Voyages connecting an EU port to a non-EU port (such as Shanghai to Rotterdam or Antwerp to New York) carry a 50% emissions liability. The EU shares jurisdictional responsibility equally with international trading partners.
- Transhipment protection rules: To prevent container vessels from bypassing European regulations by adding an offshore stop, the EU excludes container calls at non-EU transhipment ports located within 300 nautical miles of an EU port, where transhipment represents over 65% of container traffic. Stops at neighbouring hubs like Tanger Med or East Port Said do not break the voyage chain, ensuring the long-haul leg remains subject to the 50% liability.
Carriers calculate ETS surcharges by projecting fuel consumption across each trade corridor, multiplying that consumption by the prevailing EUA market price, and dividing the cost across available container slots. Specialised equipment, particularly refrigerated containers (reefers), incurs higher surcharges because reefer units draw auxiliary electric power generated by the ship engines throughout the voyage.
How CBAM functions in the definitive regime
CBAM entered its definitive regime on 1 January 2026. For covered cement, fertilisers, iron and steel, and aluminium goods, importers whose combined net imports do not exceed 50 tonnes in a calendar year are exempt from CBAM obligations. This is a cumulative threshold per importer, not a per-shipment allowance. Above it, the exemption is lost for that year's covered imports. The threshold does not apply to electricity or hydrogen. Importers or their indirect customs representatives subject to CBAM need authorised declarant status; see the Commission's authorisation guidance.
Certificate purchases begin in February 2027, including purchases for 2026 imports. Those 2026 imports use the EU ETS auction-price average for the quarter in which the goods were imported. Weekly pricing applies from 2027 onwards, according to the Commission's CBAM certificate pricing rules. The embedded-emissions calculation concerns production, rather than the ocean freight leg:
- Direct emissions: Greenhouse gases released directly during manufacturing, such as smelting ore in a blast furnace, heating steel rolling mills, or chemical reactions in fertiliser synthesis.
- Indirect emissions: Emissions originating from the generation of electricity consumed during manufacturing processes. Certain sectors, such as steel and aluminium, have specific rules regarding indirect emission inclusion.
- Specific embedded emissions formula: Total greenhouse gas tonnes divided by the net output tonnage of the installation, yielding a specific carbon factor (t CO2e per tonne of goods).
Where default values are used for goods other than electricity, the baseline is the average emission intensity for the exporting country and the relevant goods, increased by a prescribed markup. If reliable country data is unavailable for those goods, the fallback uses the average emission intensity of the ten highest-emitting exporting countries for which reliable data is available. It is not an average of the highest-emitting individual factories. See Annex IV, section 4.1 of the amended CBAM Regulation and the Commission's default-value rules. Defaults can increase certificate costs compared with lower, verified installation emissions; compare the applicable published value with your supplier's verified data.
Comparing EU ETS Maritime and CBAM side by side
- What is taxed: EU ETS taxes the fuel burned by the vessel. CBAM taxes the greenhouse gases emitted while fabricating the goods.
- Who is legally liable: Under EU ETS, the shipping line or ship management company holds the legal compliance obligation. Under CBAM, the registered EU importer or indirect customs representative holds legal liability.
- How costs are collected: EU ETS costs reach the cargo owner as a commercial freight surcharge on ocean invoices. CBAM declarants buy certificates from their national competent authority through the common central platform and surrender the required certificates annually through the CBAM Registry.
- Goods affected: EU ETS applies across all commercial container cargo on covered vessels regardless of commodity. CBAM applies only to designated goods classified under specific CN codes in iron, steel, aluminium, cement, fertilisers, and hydrogen.
Practical steps to audit freight carbon charges
Logistics and trade compliance teams can protect their operations from excessive carbon costs by adopting a structured audit workflow:
- Benchmark maritime ETS surcharges against market data: Review carrier ETS line items against sea distance, container equipment type, and prevailing EUA allowance prices. If a carrier charges 50 euros per TEU on a corridor where standard fuel models indicate 20 euros of emissions liability, request their calculation breakdown.
- Isolate Scope 3 transport data from customs filings: Record ocean container transport emissions using ISO 14083 compliant tools for internal sustainability reporting and CSRD disclosures. Do not enter freight transport emissions into CBAM customs declarations.
- Obtain primary manufacturing data early: Engage overseas suppliers to secure verified installation emission reports. Compare those emissions with the applicable published defaults; defaults can cost more when the supplier's verified emissions are lower.
- Verify commodity classification: Confirm that goods are classified under exact 8-digit CN codes. A classification error can subject exempt goods to unnecessary CBAM scrutiny or trigger reporting penalties.
The bottom line
Managing carbon costs in international shipping requires keeping transport emissions and product manufacturing emissions in their respective lanes. EU ETS Maritime addresses the bunker fuel burned by container vessels, and carriers pass that cost through freight invoices. CBAM addresses the factory emissions generated when fabricating basic materials abroad, paid directly by importers through European carbon certificates. Calculating container carbon footprints under ISO 14083 gives you the visibility needed to audit carrier surcharges, report Scope 3 emissions accurately, and prepare for future environmental regulations.