How do I demonstrate the CO2 emissions per tonne of aluminium?

What you must concretely do

What is expected of you

CO₂ emissions per ton of aluminium is a figure that appears in multiple places, each with its own framework and its own burden of proof. Different rules, different forms, and at present also no definitive calculation method for the passport itself apply to the digital product passport and to CBAM. This makes the subject confusing, but the obligations can be broken down.

A calculation according to an established method

For the digital product passport, measurements and calculations may not be freely chosen: Article 39 of the ESPR (Regulation (EU) 2024/1781) stipulates that testing, measurement and calculation are carried out according to methods established for the product component. For aluminium, that method for CO₂ per ton has not yet been published. In practical terms, this means for a company with 10 to 100 employees that its own calculation method — however carefully drawn up — will have to be replaced once the official method is available. If a company is already working with greenhouse gas accounting, for example for a customer or for CBAM, it is well advised to keep those figures and the underlying source data separately, so that a later conversion to the official method does not mean that everything has to be collected again. More information on the status of that method can be found on the page about the method by which the values for the passport are measured.

Demonstrating the origin of the figure

A CO₂ figure per ton is only useful if it is clear where it comes from: from which factory, which process, which energy mix. For a company that purchases and processes aluminium, this means that the origin of the figure — not only the figure itself — must be recorded. In aluminium, emissions per ton vary widely between primary aluminium (electrolysis) and recycled aluminium (remelting), and the two must not be mixed into a single average without it being clear how that average is composed. This also touches on the question of how much recycled material is in a batch; those two figures — CO₂ per ton and the proportion of recycled aluminium — belong together and are often asked in one breath. See also how the proportion of recycled aluminium is demonstrated.

CBAM as a separate, already existing process

Separately from the product passport, CBAM already exists: Regulation (EU) 2023/956 requires a declarant on import of aluminium from outside the EU to report the embedded greenhouse gas emissions. For a company importing aluminium, this is therefore not a future obligation but a current one. The figures drawn up for CBAM — per ton, per product category, per installation of origin — are not automatically the same figures that will later appear in the product passport, because the systems have been set up separately, but the underlying source data (energy consumption, process data from the producer) are often reusable. What CBAM exactly requires and for whom is set out on the page on CBAM and aluminium.

Distinction between file and passport

For a company that is already having a CO₂ calculation made — for a customer, for a sustainability report, for CBAM — the distinction between what remains internal and what will later be public in the passport is relevant. The passport shows an established figure according to an established method; the underlying calculation model, the assumptions and the source data remain outside it. That distinction between the technical file and the digital product passport is precisely where many companies get stuck, and is explained on the page on the difference between technical file and passport.

Where things go wrong in practice

A supplier provides one CO₂ figure per ton for an entire annual production, while that production consists partly of primary and partly of recycled aluminium. The average figure is then not traceable to a specific batch, and when asked for substantiation, there is no breakdown available.

Another scenario: a company uses for the product passport the same CO₂ value it has also stated for CBAM, without checking whether the scope and calculation rules match. CBAM uses its own system for embedded emissions in imports; this is not directly interchangeable with a method that will be established later for the passport.

A third situation: an importer of aluminium semi-finished products takes over the CO₂ figure from the foreign producer without source documents, and cannot provide anything more than an email or a line on a quotation when asked for evidence.

A fourth situation: a company calculates a CO₂ value itself using its own calculation model, assuming this can be automatically transferred to the product passport later. Once the official method under Article 39 of the ESPR is published, the own approach turns out to deviate in some respects, and the figure must be rebuilt — something that could have been prevented by keeping the source data structured from the outset.

A fifth: a company thinks the CO₂ figure is a confidential business secret and does not want to share it with the party compiling the passport, while it is unclear which part of that information will later be public and which part can remain protected. That consideration belongs to the question whether business-sensitive data on aluminium must be made public, and is different from the question of who may access the data, which is answered on the page on who may see which data from the product passport.

What you can document now

• Per batch or production lot: the CO₂ figure per tonne, with indication of the calculation method or tool used and its version.
• The source of the figure: factory, process line, and whether it concerns primary or recycled aluminium, or a mixing ratio.
• The source data on which the figure is based: energy consumption, energy mix, process data from the producer — kept separately from the final figure itself.
• For imported aluminium: the CBAM reporting and the underlying data from the foreign producer or installation.
• A note with each figure on whether it is intended for CBAM, for a customer request, or for future use in the product passport, so that scope and method do not become confused.
• A reference to the alloy and EN-AW designation of the batch in question, because CO₂ figures can differ per alloy; see how the alloy and the EN-AW designation are recorded.