CBAM and Machined Metal Parts: The Supplier View
If you import machined metal parts into the EU, the Carbon Border Adjustment Mechanism has probably already reached your inbox in the form of a supplier questionnaire asking for embedded emissions per kilogram. If you are the supplier being asked, the request may look unreasonable: you machine a bracket, you do not smelt aluminium.
Both reactions are understandable, and both need a more careful answer than either side usually gives. This is a practical account of where CBAM touches machined parts, what data actually matters, and what a machine shop can and cannot provide.
Nothing here is legal advice. Whether a specific part falls in scope depends on its CN classification, its importer and the version of the regulation in force, so confirm with your customs broker and compliance team.
Which parts are in scope
CBAM covers goods listed in Annex I of Regulation (EU) 2023/956, organised by CN code, across six sectors: cement, iron and steel, aluminium, fertilisers, electricity and hydrogen.
For machined parts the relevant sectors are iron and steel and aluminium. That includes a long list of CN codes covering flat and long products, tubes, and a set of articles further downstream. Some fabricated articles under CN chapters 73 and 76 are listed; others are not. The practical rule is that scope follows the CN code on your customs declaration, not the fact that a part is made of steel.
Two complications matter. The Commission has consulted on extending scope to downstream articles, so a part outside Annex I today may not stay outside. And some codes cover products defined by function rather than process, which makes classification itself the first argument.
If you do not know the CN code, ask your importer; they declare it.
How embedded emissions are calculated
Embedded emissions for a CBAM good are, broadly, the direct emissions from producing it plus the indirect emissions from the electricity consumed, allocated to the mass of the good. The method attributes emissions from precursors — the billet, slab or ingot that went into your part — as well as the emissions of the production steps inside the installation that made the good.
That precursor attribution is why a machine shop cannot answer alone. The aluminium billet carries most of the carbon. Machining carries relatively little.
A worked example makes the split obvious. Take an aluminium bracket with a finished mass of 0.9 kg, machined from 2.3 kg of billet, with 1.4 kg of chips returned as scrap.
- Billet: 2.3 kg at roughly 8-9 kg CO2e per kg for primary European aluminium = about 19-21 kg CO2e.
- Machining electricity: 18 minutes at an average 12 kW draw = 3.6 kWh, at 0.35 kg CO2e per kWh = about 1.3 kg CO2e.
- Total embedded: roughly 20-22 kg CO2e, of which machining is around 6%.
That ratio is the most useful thing to explain to a customer: the lever is the material and its production route, not the spindle. Recycled billet at around 0.5 kg CO2e per kg would cut the total by 80% before anyone touches a machine.
Default values exist for importers who cannot obtain actual data. They are conservative by design and generally produce a higher declared figure than verified actual data. If your customer is paying for certificates based on defaults, actual data from the mill is worth real money to them — which is the commercial argument for cooperating.
See also: Sending CAD Data to a Machine Shop: What to Control and Export Control and Machined Parts: ECCN, EAR99 and Deemed Export.
What a machine shop can actually provide
A machining supplier can credibly supply:
- Electricity consumption attributable to the part, from machine monitoring or from an allocation of shop kWh over shipped parts.
- Process energy for finishing steps carried out in-house, such as deburring, washing and laser marking.
- Scrap mass and where it went, since recycled chips have a different treatment from chips sent to landfill.
- Material certificates naming the mill, grade and heat number, which lets the importer trace the precursor.
- Subcontractor details for anodizing or heat treatment, which have their own energy consumption.
A shop should not be asked to certify the emissions of the mill: that data belongs to the producer of the precursor.
The reporting timeline
| Period | Obligation | Who files | Data required |
|---|---|---|---|
| Oct 2023 – Dec 2024 | Quarterly CBAM report | EU importer | CN code, mass, direct and indirect emissions; default values permitted |
| Jan – Dec 2025 | Quarterly CBAM report | EU importer | Same, with actual values preferred and default values still allowed |
| From Jan 2026 | Definitive regime: annual declaration | EU importer | Verified embedded emissions, reported per installation |
| By 30 Sep each year | Declaration for the previous year | EU importer | Verified data; certificates surrendered against declared emissions |
| Ongoing | Supplier data requests | You, the supplier | Electricity, mass, scrap, precursor origin, subcontractor processes |
Note the direction of the legal obligation: it sits on the importer, not on you. You are not a CBAM declarant. What you are is the only practical source of installation-level data, which is why the request arrives.
A mass threshold for small importers — 50 tonnes per year per importer — was introduced to keep small consignments out of the definitive regime. Whether your customer is above or below it is their calculation, and it can change with a single new project.
What to send, and what to say instead of a number
The most useful response to an emissions request is a structured document, not a figure in an email. Ours lists, per part number: finished mass, input mass, material grade and mill, machine hours and kWh, finishing steps, scrap route, and the share of shop electricity allocated. It states clearly that precursor emissions are excluded and must be obtained from the mill.
If you cannot measure machine-level kWh, say so and offer an allocation method: total shop consumption divided by machine hours, then by parts. That is a defensible estimate, and it is far more useful than a made-up precise number. What destroys credibility is a figure with four decimal places and no method behind it.
For parts with several finishing steps, list them separately. Anodizing is electricity-intensive relative to machining, and hiding it inside a machining figure will not survive a customer's own verification process.
Our materials page lists the grades we hold and the mill documentation that comes with them, and contact is the place to ask for a per-part energy breakdown before you commit to a declaration. We can provide machining energy and mass data; the precursor emissions have to come from the metal producer.
Frequently asked questions
Are all machined steel or aluminium parts covered by CBAM?
No. Coverage follows the CN code in Annex I, and some machined and fabricated articles are listed while others are not. A part can be functionally identical to a covered article and still fall outside because of how it is classified. Get the code from the importer's customs declaration and confirm scope against the regulation in force at the time of import.
Can a machine shop provide verified embedded emissions data?
It can provide the machining portion with a documented method, but verification applies to the installation producing the CBAM good and to the declaration made by the importer. A shop's electricity figures are an input to that process, not a substitute for it. Expect the importer's verifier to ask how the allocation was done.
Does the machining step matter at all if it is only 6% of emissions?
It matters at the margin and it matters for accuracy, but it is not where the reduction opportunity sits. Switching to recycled billet or a lower-carbon primary supply changes the total by a factor of five to ten; halving machining energy changes it by 3%. Buyers who focus only on the machining number are optimising the wrong variable.
What happens if we cannot supply any data?
The importer can use default values, which are typically higher than actual and cost more in certificates. The commercial consequence lands on them, and eventually on the price they are willing to pay you. Providing a documented estimate is almost always better than providing nothing, provided you are explicit about what is measured and what is assumed.
Related reading
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