Embedded Carbon Record vs CBAM Declaration vs O3CI
CBAM compliance involves three distinct components operated by different parties. Understanding the difference between the manufacturer's record, the importer's declaration, and the government portal is critical for compliance.
| Component | Who is responsible? | What is it? | When is it needed? |
|---|---|---|---|
| Embedded Carbon Record | Non-EU Manufacturer (Installation Operator) | Verified calculation of tCO2e per tonne of product, audited by an ISO 14065 body. | Before export / at time of supply contract negotiation. |
| CBAM Declaration | EU Importer (Authorised CBAM Declarant) | Annual legal filing aggregating total imported volumes and calculating total certificates owed. | By May 31 annually (covering the previous calendar year). |
| O3CI Portal | European Commission (Operator) | The central IT infrastructure and database where declarations are submitted and certificates surrendered. | Ongoing platform access required for compliance. |
Before comparing the three components, see: What Is an Embedded Carbon Record? — the product-specific definition guide.
The Three Pillars of CBAM Compliance
The Carbon Border Adjustment Mechanism is a complex regulatory framework that requires coordination between parties operating in different legal jurisdictions. A common point of failure in CBAM compliance is confusion over roles: who produces the data, who files the legal paperwork, and where does it all go?
Understanding the distinct functions of the Embedded Carbon Record, the CBAM Declaration, and the O3CI portal is critical for establishing functional supply chain compliance pipelines.
When to focus on the Embedded Carbon Record
- If you are a manufacturer located outside the European Union producing steel, aluminium, cement, fertilisers, or hydrogen.
- When engaging an ISO 14065 accredited verification body to audit your facility's emissions.
- When establishing a permanent, SHA-256 hashed document vault to prove the authenticity of your emissions data to multiple EU buyers.
- When competing for EU supply contracts, where a verified low embedded carbon record provides a direct pricing advantage over competitors using EU default values.
When to focus on the CBAM Declaration
- If you are an EU-based importer or an indirect customs representative.
- When calculating your annual financial liability and purchasing CBAM certificates.
- When applying to your national competent authority for "Authorised CBAM Declarant" status (mandatory for importing covered goods from 2026).
- When facing the May 31 annual deadline for submitting the formal regulatory filing.
When to focus on the O3CI Portal
- When navigating the European Commission's IT infrastructure to submit reports or declarations.
- When a non-EU manufacturer wishes to upload their embedded carbon record directly to the EU registry to protect commercially sensitive data from being seen by the importer (using the O3CI operator delegation feature).
- When managing UUM&DS (Uniform User Management and Digital Signature) authentication credentials.
Real-world example: The Secure Data Pipeline
An Indian aluminium smelter (the non-EU manufacturer) calculates its direct and indirect emissions. It hires an accredited verifier who audits the data and produces a verified Embedded Carbon Record showing 4.2 tCO₂e/t. The smelter hashes and stores this record in a permanent vault, generating a secure URL.
The smelter sells 1,000 tonnes of aluminium to a German automotive parts manufacturer (the EU importer). The German company is an Authorised CBAM Declarant.
In May 2027, the German importer logs into the O3CI Portal. They begin drafting their annual CBAM Declaration. They input the 1,000 tonnes imported, and provide the vault URL for the Indian smelter's Embedded Carbon Record to prove the 4.2 tCO₂e/t intensity. The O3CI portal calculates that the importer owes 4,200 CBAM certificates. The importer surrenders the certificates within the portal, completing the compliance cycle.
Common misconceptions
- "The non-EU manufacturer files the CBAM declaration." False. The legal obligation to file the declaration and pay the tax rests entirely with the EU importer. The manufacturer's only role is to supply the Embedded Carbon Record.
- "O3CI is a calculation tool." False. The O3CI portal does not calculate your facility's emissions. It is a submission registry. You must perform the calculations externally according to Annex IV methodologies before logging in.
- "The importer verifies the data." False. The importer relies on the verification statement produced by the manufacturer's ISO 14065 accredited auditor. The importer is liable if they submit unverified data, but they do not perform the verification themselves.
Regulatory citations
The requirement for the EU importer to submit the CBAM Declaration is established in Regulation (EU) 2023/956, Article 6.
The methodology for producing the Embedded Carbon Record (calculation of actual embedded emissions) is defined in Article 7 and Annex IV of the same Regulation.
The establishment of the CBAM Registry (O3CI) is mandated by Article 14.
Frequently Asked Questions
Who is responsible for the Embedded Carbon Record?
The non-EU manufacturer (the "installation operator" in CBAM terminology) is responsible for producing and storing the Embedded Carbon Record. This involves calculating actual embedded emissions per Annex IV methodology, engaging an ISO 14065 accredited verifier to audit the calculation, and providing the verified record to EU buyers.
Who files the CBAM Declaration?
The EU importer (the "Authorised CBAM Declarant") files the annual CBAM Declaration. This is a legal obligation due by 31 May of the following year. The declarant aggregates all imports of covered goods, applies the verified embedded carbon intensities provided by manufacturers, calculates total CBAM certificates owed, and surrenders them via the O3CI portal.
What is the O3CI portal?
The O3CI (CBAM Transitional Registry, later the CBAM Registry) is the IT system operated by the European Commission where EU importers submit their declarations and surrender CBAM certificates. Non-EU installation operators can also register in the O3CI to submit their emissions data directly, using the operator delegation feature to share data with their EU buyers without revealing commercially sensitive production details.
Can a non-EU manufacturer submit data directly to the O3CI?
Yes. Non-EU installation operators can register in the O3CI portal and submit their verified embedded carbon data directly. This is particularly useful when a manufacturer supplies multiple EU buyers and wants to avoid sharing detailed production data with each buyer individually. The O3CI operator delegation feature allows the manufacturer to control their data while making it available to authorised declarants.
What happens if the EU importer does not have the manufacturer's Embedded Carbon Record?
If the EU importer cannot obtain verified actual embedded carbon data from the manufacturer, they must use EU default values. Default values are set at the 90th percentile of EU production and are typically 2–3 times higher than actual emissions for modern non-EU facilities. This results in significantly higher CBAM certificate costs for the importer, which they will typically pass back to the manufacturer through lower purchase prices or contract penalties.