What you’re doing in this workflow

You’re building a 12-month CBAM dataset for one installation (site) that your customers (EU importers or downstream insatllations) can use for their CBAM reporting or declarations. The dataset needs to:

Clearly define the installation, reporting period, and CBAM goods produced
Capture all relevant emission sources within the CBAM system boundary for your sector
Allocate precursors + energy + emissions to the production processes that create your CBAM goods

Before you start

Have these ready (or know who owns them internally):

Your reporting period (ideally a continuous 12 months) and matching activity data
A list of CBAM goods you produce (and their CN codes if you have them)
A list of CBAM in-scope precursors you purchase and consume (steel/aluminium inputs)
Annual totals for:
- Fuels combusted on site (by fuel type)
- Electricity purchased and/or generated (MWh)
- Process emissions you track (e.g., carbonates, electrodes/anodes, flue gas cleaning, anode effects)
If you buy CBAM precursors: supplier embedded emissions values (or their summary communication)

Step-by-step (matches the in-product flow)

1) Setup an installation

Goal: Create the installation record you’ll complete.

Create the installation for the physical site where production happens (not the HQ entity if different).
If your company operates multiple sites: create one installation per site.

2) Define installation information

Goal: Make the dataset unambiguous for downstream users.

Include:

Site location identifiers (use a consistent location reference)
Operator or legal entity details for the installation

3) Choose what you’re doing: upload a Summary Communication file vs preparing data via CarbonChain

Goal: Decide your fastest path to preparing or sharing data.

If you already have a completed CBAM communication summary sheet: upload it and you will receive a review and be able to share data through the platform.
If not: start adding activity data step-by-step (recommended for first-time users).

4) Select your 12-month reporting window

The regulation requires you to use a continuous 12-month period that aligns with how you can reliably pull the following data. Note that the first verification will happen over 2026 calendar year data therefore, if you currently only prepare 3 month data you should prepare a rolling 12-month dataset, updated every 3 months. This data should capture the following:

production volumes
fuel + electricity consumption
onsite process emissions
precursor consumption

5) Start with the products you are producing

Goal: Define the CBAM goods your processes create.

List each CBAM good you produce at this installation, based on CN Code as the functional unit.

Common mistake: Using purchased or sold goods volume rather than goods produced during the year to which the emissions are being allocated.

6) Add the products you make - and define intermediate products correctly

Remember that as part of a verification you will be required to detail the source of all numbers used to specifcy volumes of gooods produced.

Detail products that you manufacture on site - the functional unit is the CN code for aluminium and steel products; except in specific permitted circumstances.
Intermediate products must be defined where goods are consumed as part of a process on site (e.g. if you make aluminium rods and they are consumed in production process no site to make aluminium wires).

7) Add in-scope input materials (CBAM precursors)

Capture the CBAM goods you consume in your production processes in order to make your end products.

Add purchased steel/aluminium CBAM goods you use as inputs by CN Code.
Remove anything not actually used in producing your listed CBAM products.

For many steel and aluminium producers, precursor embedded emissions are a significant part of total embedded emissions.

8) Add electricity and fuel supplies

Goal: Capture all energy inputs that drive your production processes.

Add fuels combusted on-site tied to your CBAM goods production processes from static machines (i.e. exclude vehicle fuels).
Add electricity purchased and/or generated (MWh), you will be able to allocate these fuels later.

If you can’t separate electricity vs non-electricity in your records (e.g., CHP): enter the full fuel amount and allocate appropriately later, avoiding double counting.

9) Add process emissions (if relevant)

Capture emissions that are not simply “fuel combustion” - and are sector-specific.

Aluminium specific process emissions

Primary smelting: include emissions from electrodes/anode paste consumption, fuels (drying/pre-heating/casting), flue gas treatment, and PFC emissions from anode effects.
Secondary melting/recycling: include fuels for drying/pre-heating, melting, scrap pre-treatment (de-coating/de-oiling), residue combustion, slag/skimmings treatment, and flue gas treatment.

Iron & Steel specific process emissions

Depending on your route, you may need to include:

emissions from fuels and reducing agents and waste gases (where applicable)
emissions from process materials (e.g., limestone and other carbonates) and flue gas cleaning
where relevant, electrode/electrode paste consumption and mass balance approaches for carbon in product/slag/waste

10) Select or add suppliers of your input materials

Connect each precursor input to who you bought it from.

Ensure that you have requested access to data via our CBAM Supplier Catalogue.
Add each supplier you purchased CBAM precursors from.
If you have multiple inputs from the same supplier, distinguish them clearly (by product/type).

Getting supplier embedded emissions (very important)

Where you consume CBAM precursors, you should obtain embedded emissions values from suppliers (ideally via their own dataset / summary communication). Use fallback approaches only where allowed and clearly justified.

11) Define your production processes (align to regulatory boundaries)

Create “allocation buckets” that match how CBAM expects you to define production.

What counts as a production process here?

Use processes that produce your CBAM goods and that you can reasonably allocate energy/emissions to.

Aluminium products boundary reminder

For aluminium products, include processes linked to production that emit from fuel combustion and flue gas treatment, excluding cutting, welding and finishing.

Iron/steel products boundary reminder

For iron or steel products, include processes such as re-heating, re-melting, casting, hot/cold rolling, forging, annealing, coating, galvanizing, wire drawing, pickling — excluding plating, cutting, welding and finishing.

Practical tip: If you only have site-level meters, define fewer processes (e.g., “Main rolling line (site metered)”) and document your allocation basis.

12) Allocate all precursors, electricity and fuels to your processes

Goal: Turn “site totals” into “per-product/process” embedded emissions.

Allocation rules that keep you safe:

Allocate electricity (MWh) across processes based on metering where possible; otherwise use a defensible proxy (run-time, throughput, rated power × hours, etc.).
Allocate direct emissions from fuels to goods/processes using the best available operational logic.
Allocate purchased precursor quantities to the CBAM goods they feed into (and separate any quantity used for non-CBAM outputs).

13) Review and submit

Goal: Make sure the dataset is complete, consistent, and shareable.

Final checks (quick):

Does every CBAM good have:
- production volume
- allocated electricity and fuels
- allocated direct/process emissions (where relevant)
- precursor inputs (if used)
Do totals reconcile?
- allocated electricity ≈ total electricity
- allocated fuels/emissions ≈ total fuels/emissions
Are you excluding out-of-boundary activities (e.g., cutting/welding/finishing; plating for iron/steel where excluded)?