How to prepare a CBAM report: a step-by-step guide for producers
From 2026 the CBAM report is the EU importer's annual declaration. What non-EU producers must prepare: monitoring plan, embedded emissions, verification, O3CI registration and the 30 September 2027 timeline, step by step.
How do you prepare a CBAM report? In short: from 2026 the "CBAM report" is the annual CBAM declaration that the EU importer (the authorised CBAM declarant) submits by 30 September each year; the first one, covering 2026 imports, is due on 30 September 2027. The non-EU producer's job is to supply the data behind it: identify the goods in scope, monitor installation emissions under a monitoring plan, calculate embedded emissions per tonne of product, have them checked by an accredited CBAM verifier, and share the verified data with the importer through the communication template or the CBAM Registry's O3CI portal. Without that data the importer falls back on default values, which carry a mark-up and make your product more expensive to import.
This guide is based on the European Commission's pages on the CBAM definitive regime, verification and the CBAM Registry (as of November 2026). It is written for EU buyers and for exporters in Turkey and other non-EU countries who need to work together on the first declaration. For the basics, see our CBAM guide; for what changed in 2026, read our definitive period article.
Transitional reports versus the annual declaration
Many suppliers still picture the quarterly CBAM reports of the 2023–2025 transitional period. Those ended with 2025. The definitive period that began on 1 January 2026 works differently:
| Transitional period (2023–2025) | Definitive period (from 2026) | |
|---|---|---|
| Document | Quarterly CBAM report | Annual CBAM declaration |
| Submitted by | Reporting declarant (importer) | Authorised CBAM declarant (importer or indirect customs representative above the 50-tonne threshold) |
| Deadline | After each quarter | 30 September each year, for the previous year's imports |
| Financial obligation | None | Surrender of CBAM certificates matching embedded emissions |
| Verification | Not required | Required when actual emissions are used |
The declaration is the importer's legal obligation, but its hardest part, the embedded emissions figure, can only come from the producing installation. That is what your EU customer is asking you for.
Who does what
| Actor | Role |
|---|---|
| Non-EU installation operator (exporter) | Monitors and calculates emissions using the CBAM methodology, provides evidence to the verifier, shares verified data with declarants. |
| Accredited CBAM verifier | Reviews the monitoring approach, calculations and evidence; issues one verification report per installation. |
| Authorised CBAM declarant (EU importer) | Declares quantities and embedded emissions, buys and surrenders certificates. |
| National Competent Authority | Reviews declarations and may impose penalties. |
Step by step: preparing CBAM data as a producer
- Map your goods. Compare the CN codes of everything you ship to the EU with the CBAM scope: cement, iron and steel, aluminium, fertilisers, hydrogen and electricity. Assign each product to its aggregated goods category.
- Define the installation and system boundaries. Which production processes make which goods, and which steps fall outside the boundary (in steel, for example, cutting and finishing). Each installation is treated separately.
- Write the monitoring plan. Document how each emission source is monitored (calculation or measurement), which meters and invoices are used and how data gaps are handled. This is the first thing a verifier reviews.
- Collect activity data. Fuel use (natural gas, coal, LPG), process inputs (carbonates, electrodes, reducing agents), measurable heat, electricity where the sector requires it, and purchased precursors. Records must be traceable per reporting period.
- Calculate embedded emissions. Process emissions plus the embedded emissions of precursors, divided by tonnes of product. In some sectors only direct emissions count; see our steel calculation guide for a worked example.
- Request supplier data. If you buy billets, clinker, aluminium ingot or ammonia, ask suppliers for verified embedded emissions; otherwise default values apply to those precursors.
- Get verified. Engage an accredited CBAM verifier. The first verification covers a documentation review and a site visit, and the verifier gives a reasonable assurance opinion.
- Share the data. Send results to customers with the Commission's communication template and/or register in the O3CI portal of the CBAM Registry and upload installation and emissions data. In O3CI you upload once and several declarants can use the data; for a declarant to find you, they need to share their EORI number with you.
What your EU customer will ask for
Importers usually send suppliers the Commission's communication template or their own questionnaire. Keep the following in one place, each item linked to its source:
| Item | Typical source |
|---|---|
| Installation name, address, location and operator details | Company register, site records |
| CN codes of products and production route | Export declarations, production planning |
| Reporting period and quantity produced | Production and stock records |
| Embedded emissions per tonne of product | Calculation under the monitoring plan |
| Sector-specific parameters (e.g. scrap share, clinker ratio, nitrogen content) | Quality and laboratory records |
| Origin and embedded emissions of precursors | Supplier declarations, purchasing records |
| Carbon price paid in the country of production, if any | Official payment documents |
| Verification report | Accredited verifier |
This set is refreshed every year. Once the data has a stable structure, the second year becomes largely routine, and the same fuel and energy data feeds your corporate greenhouse gas inventory; see our ISO 14064 GHG inventory software page.
What goes into the annual CBAM declaration
According to the Commission's certificate factsheet, the annual declaration reports the quantity of goods imported in the previous year, their embedded emissions and the corresponding number of certificates. In practice it rests on:
- imported quantities per CN code, country of origin and installation;
- embedded emissions per tonne: actual verified data or the Commission's default value;
- one verification report per installation where actual data is used, retrieved from the Registry;
- a deduction claim where a carbon price has actually been paid and documented in the country of production;
- the number of CBAM certificates to surrender.
Declarants enter this in the declarant portal of the CBAM Registry; installation data registered in O3CI can be pulled into the declaration automatically.
The 2026–2027 timeline
| Date | Milestone |
|---|---|
| January 2026 | Definitive period starts; importers apply for authorisation, operators start monitoring and calculating. |
| April 2026 | National accreditation bodies begin CBAM accreditation. |
| September 2026 | Accredited verifiers can register in the CBAM Registry; first verifications (document review, site visits) begin. |
| January 2027 | First verification reports can be issued and shared with declarants. |
| February 2027 | Declarants can start buying CBAM certificates. |
| 30 September 2027 | First annual declaration and certificate surrender for 2026. |
For a supplier this means 2026 production data should be verified in the first half of 2027. Verifier capacity is limited, so start the conversation now.
Actual data or default values?
Importers can declare embedded emissions using the installation's verified actual data or the Commission's country-specific default values. In the definitive period default values carry a mark-up: 10% in 2026, 20% in 2027 and 30% from 2028 (1% for fertilisers). Defaults are easy but usually higher than real performance, and the gap shows up in the number of certificates your customer must buy, and so in price negotiations. For an efficient plant, verified actual data is a direct commercial advantage.
Common mistakes
- Treating a corporate carbon footprint as CBAM data. An ISO 14064-1 inventory is company-wide and annual; CBAM is per product and installation, under its own method. The raw data overlaps, the result does not. See our scope 1, 2, 3 article.
- Leaving out precursors. If the embedded emissions of purchased billets, clinker or ingots are missing, the figure is incomplete and will not pass verification.
- Losing the audit trail in spreadsheets. Verifiers want to trace every number to an invoice, meter reading or lab report; copied tables break that trail. We cover the risks and safeguards in carbon accounting in Excel vs software.
- Leaving verification to the last minute. Site visits and corrections take time; plan backwards from 30 September 2027.
- Sending a different file to every customer. One verified data set, registered in O3CI, scales as your customer list grows.
Preparing CBAM data with Carbonet
Carbonet is CBAM and carbon footprint software developed by LNA Soft in Izmir, Turkey. You define installations, processes and products once; fuel, process and precursor data are stored with their source documents; embedded emissions per product are calculated and the trail a verifier needs is kept. The same data also produces your ISO 14064-1 inventory. Details are on our CBAM embedded emissions calculation page.
To try it with your own products, request a demo or write to info@carbonet.com.tr or WhatsApp +90 533 368 05 99.
Frequently asked questions
Who submits the CBAM report, the exporter or the importer?
In the definitive period the annual CBAM declaration is submitted by the authorised CBAM declarant in the EU, which is the importer or its indirect customs representative. The non-EU exporter does not file it, but calculates, verifies and shares the embedded emissions data per product that goes into it.
When is the first annual CBAM declaration due?
The first annual declaration and certificate surrender, covering imports made in 2026, is due on 30 September 2027. After that, each year's imports are declared by 30 September of the following year.
Do quarterly CBAM reports still exist?
No. Quarterly reports belonged to the 2023–2025 transitional period and ended with 2025. Since 1 January 2026 they have been replaced by the annual declaration and the surrender of certificates.
Is verification mandatory?
Yes, if the importer wants to use the installation's actual emissions. The data must be verified by a CBAM verifier accredited by an EU national accreditation body. Verification is done per installation and the first one includes a site visit. Without verified data, default values are used.
Do producers have to register in the O3CI portal?
O3CI lets non-EU installation operators upload installation and emissions data to the CBAM Registry once and share it with several declarants. Data can also be sent with the communication template, but with several EU customers O3CI reduces workload and lets declarants pre-fill their declarations.