European aluminium importers face two distinct sources of carbon-related costs within a single shipment: the embedded emissions liability under the Carbon Border Adjustment Mechanism (CBAM) and the carbon cost associated with maritime transport under the EU Emissions Trading System (EU ETS).
The two obligations apply to different activities, but both can transmit movements in the European carbon market into the final delivered cost of imported metal.
Maritime transport enters the EU carbon market
The EU ETS has covered maritime transport since 2024. For ships within the scope of the system, shipping companies must account for 50% of emissions from voyages between an EU port and a non-EU port, while 100% of emissions from voyages between EU ports and emissions occurring within EU ports are covered.
From 2026, the maritime ETS framework also includes methane and nitrous oxide, in addition to carbon dioxide.
For aluminium buyers, this creates a freight-related carbon exposure alongside the CBAM liability attached to the metal’s embedded emissions. Although the two mechanisms impose separate legal obligations, their commercial effects can be connected through the price of EU allowances (EUAs).
One EUA market, two cost channels
When EUA prices rise, an importer may face higher expected CBAM certificate costs while shipping companies may also seek to recover increased maritime compliance expenses through freight charges.
The result is a correlated exposure across two parts of the import transaction. A company that hedges the embedded emissions of its aluminium but excludes the carbon component of ocean freight may underestimate its total sensitivity to the EU carbon market.
During a sharp increase in EUA prices, both the border-related liability and the shipping surcharge can move upwards, amplifying the impact on the landed price of aluminium.
Freight contracts become part of carbon risk management
Importers therefore need to examine how maritime ETS costs are treated in their freight agreements. Relevant commercial arrangements include whether the carbon charge is fixed, variable, transparently passed through or incorporated into a bunker adjustment mechanism.
Companies should also check whether freight indices or all-in shipping rates already include an ETS-related surcharge. Without this distinction, carbon costs may be counted twice in internal landed-cost calculations.
For large aluminium import programmes, a consolidated EUA sensitivity analysis can help quantify the combined exposure. An importer could assess how a €10/tCO2 increase in the allowance price affects both its estimated CBAM liability and the expected carbon-related freight surcharge, then determine whether its hedging strategy should reflect the combined exposure.
The CBAM and maritime ETS remain separate regulatory mechanisms, but their interaction makes shipping carbon costs an increasingly important component of aluminium procurement, freight contracting and treasury risk management.
