What Is CBAM? EU & UK Rules Explained..

CBAM (Carbon Border Adjustment Mechanism) is an EU policy that puts a carbon cost on specific imports so they face a comparable carbon price to goods made under domestic EU & UK carbon policies. 

The intent is simple: discourage carbon leakage and push global supply chains towards lower‑emission production. For engineers, buyers and operations teams, it changes how you evaluate materials, suppliers and landed cost.

This article covers CBAM in its terms, scope and global remit, looking at what commodities are affected in each market from a top-level.

Contents:

• CBAM at a Glance: What It Is and Why It Exists.

• CBAM Key Terms.

• EU CBAM: Scope, timelines, costs, exemptions, what’s changing.

• UK CBAM: Scope, design choices, how it differs from the EU.

• Common pitfalls and how to avoid them.

• FAQs
  
  

Disclaimer: Information is accurate on the date of publication (November 2025), CBAM is constantly changing, and we will update this article as regulations change.

CBAM at a Glance: What It Is and Why It Exists.

CBAM: the Carbon Border Adjustment Mechanism, is an EU policy designed to apply a carbon price at the border on selected imports.
It went live in 2023 with a reporting‑only phase and is now being phased in so that imported goods bear a comparable carbon cost to those produced under the EU Emissions Trading System (EU ETS).

The ETS is a "cap-and-trade" market mechanism, designed to cost-effectively reduce greenhouse gas emissions from heavy industry, power generation, aviation and maritime transport by setting a gradually decreasing limit on total greenhouse emissions and allowing companies to trade allowances.
The UK plans to introduce its own CBAM on January 1st 2027, calibrated to the equivalent UK ETS(Emissions Trading System).

What CBAM aims to do.

Prevent carbon leakage: stop production (and emissions) shifting to countries with weaker climate rules.

Level the playing field: ensure EU‑regulated manufacturers aren’t undercut by carbon‑intensive imports.

Drive global decarbonisation: create market pressure on overseas producers to cut their embedded emissions.

Improve data transparency: normalise the disclosure of embedded (embodied) emissions across supply chains.

Why was the policy put in place?

As the EU tightened climate policy and reduced free allowances under the EU ETS, the risk grew that emissions‑heavy production would migrate to lower‑regulation regions, undermining climate goals and European industry.
CBAM tackles this by aligning import costs with domestic carbon constraints, so the price signal to decarbonise applies whether a product is made inside or outside the EU. It also encourages comparable carbon pricing internationally, nudging trading partners toward equivalent measures.

How it works in outline.

Importers of in‑scope goods must quantify embedded production emissions and, once the charging phase of CBAM begins to apply, account for them at a border carbon rate linked to the domestic carbon market.

Where a valid carbon price has already been paid in the country of origin, that amount can be credited to avoid double‑charging.
Initial coverage focuses on carbon‑intensive materials (e.g., iron and steel, aluminium, cement, fertilisers, electricity, hydrogen), with scope and requirements expected to evolve as the policy matures and the UK scheme goes live in 2027.

Key terms.

• Embedded (or embodied) emissions: Greenhouse gases released across the processes needed to make a product (e.g., iron ore to finished steel), expressed as tCO₂e per tonne.

• Direct vs indirect emissions: Direct emissions come from on-site processes and fuel use. Indirect emissions cover the off-site activities needed to produce the materials, energy or inputs used in that process; this includes international trade.

• Precursors: Inputs whose emissions must be counted because they’re significant in the final product (e.g., hot metal used to make steel products).

• Carbon leakage: Lost climate impact visibility when production moves to laxer jurisdictions, undercutting decarbonisation at home.

• Authorised CBAM declarant: The legal entity allowed to import CBAM goods and responsible for compliance.
  
  

EU CBAM: scope, timelines, costs, exemptions, what’s changing.

What goods are in scope?

The EU currently targets imports in cement, iron & steel, aluminium, fertilisers, electricity and hydrogen. Within iron, steel and aluminium, coverage is defined by CN codes and spans a wide set of semi‑finished and selected downstream items (e.g., tubes, profiles, structures; in iron & steel, this includes fasteners under HS 7318).
Always check the exact CN code for your product before assuming it’s in or out of scope. 

Timelines you need to know.

• Transitional phase (report‑only): 1 Oct 2023 – 31 Dec 2025. Importers submit quarterly CBAM reports on embedded emissions for in‑scope goods. No certificate purchases during this phase. Taxation and Customs Union

• Definitive policy regime (cost applies): The EU has shifted the first purchase and surrender dates of CBAM certificates to 2027 for calendar‑year 2026 imports. The first annual CBAM declaration and certificate surrender filings are due by 30 September 2027, then annually.

Who can import and how are costs set?

• Authorisation: From 2025, importers (or indirect customs representatives) must apply in the CBAM Registry for authorised CBAM declarant status with their Member State authority.
  This status becomes a practical precondition to import CBAM goods under the definitive regime. Register for EU-CBAM,

• Price of CBAM certificates: Set by the Commission using the average weekly EU ETS auction price (€/tCO₂). This mirrors the domestic carbon price signal. 

• Credit for foreign carbon prices: If a carbon price has been paid on the product in the country of origin, the importer can deduct that amount from the CBAM liability (documentation required).

Exemptions and simplifications (2025 amendment)

To simplify CBAM and focus on the bulk of emissions:

• A 50‑tonne annual mass threshold applies; small, low‑volume importers are largely out of scope.

• Certificate purchase/return and first CBAM declaration for 2026 imports are due in 2027 (see above).
  These changes were enacted by Regulation (EU) 2025/2083, which amends the original CBAM Regulation.

What might change next?

The EU Commission is conducting a 2025 review exploring: extending CBAM to downstream steel/aluminium products; broadening product/commodity sectoral scope and treatment of indirect emissions. A public consultation on future expansion ran in mid‑2025. The upcoming potential changes are key to keep in mind if you import or sell fabricated goods and not just raw materials.

UK CBAM: scope, design choices, differences from the EU.

The UK will introduce a UK CBAM from 1 January 2027. It will initially cover imports in aluminium, cement, fertilisers, hydrogen, iron & steel.
Electricity is not included at launch. The government removed glass and ceramics from the initial scope, but as with the EU scheme, changes to the policy are ongoing.

How the UK will calculate liability.

Emissions coverage: The UK will price direct, indirect and selected precursor emissions to align with the UK ETS coverage. Importers may use actual data or government‑set default values (one default per product) where actual emissions values are unavailable. Learn More About UK CBAM Emissions Coverage. 

CBAM rate: Benchmarked to the UK ETS carbon price, net of any free allowances or domestic reliefs and crediting explicit carbon prices paid overseas; so the UK focuses on price differentials rather than double‑charging importers. 

Product list: Published by commodity code in Annexe B of the government’s response. Scrap is excluded. A review of the scope is planned after 2027. You can view the full commodity code scope on the UK Government Website. 

EU/UK ETS linkage and CBAM interaction.

In 2025, the EU and UK committed to negotiating a link to their ETS policies. If concluded, linkage will enable mutual CBAM exemptions (i.e., no CBAM at the EU–UK border for covered sectors) because both sides would face an aligned carbon price.

Negotiations are still ongoing and the current Plan for the UK CBAM from 2027 is with a linked ETS, but monitor talks closely as the filing date approaches. If you want to get organised early, consider a UK CBAM consultation with a registered tax advisor. 

Common pitfalls and how to avoid them

• Wrong tariff code: Misclassification can create unexpected scope (or missed liabilities). Align classification with product function (e.g., fastening vs spring action).

• Ignoring precursors/indirects: Leaving out upstream process steps or grid power leads to under‑reported emissions, which can result in penalties.

• Assuming de minimis value thresholds still apply: The EU has moved to a mass‑based de minimis (50 tonnes/year). Check annual volumes, not only individual shipment value.

• Late EU authorisation: Without authorised declarant status, future imports can be stopped at the border. Ensure you get the application in early and maintain registry hygiene for ease of filing.

• Over‑relying on defaults: Defaults are a bridge, not a strategy. Higher‑than‑actual defaults will inflate costs; invest in supplier data and verification capability early on to save in this area where volumes warrant it.

• Not planning for scope expansion: Downstream products may enter the EU CBAM in future and come to other policies globally later on. Treat 2025–2026 as time to future‑proof data models and begin recording this data for future use. 

FAQs

Q: How can Accu help with CBAM?

Currently, Accu can only provide estimated carbon emissions on a per-order basis. These estimated carbon emissions are calculated based on a study provisioned by the European Commission.

Q: What is CBAM in simple words?

A: A rule that prices the carbon in certain imports so they face a similar carbon cost to domestic goods, discouraging carbon leakage.

Q: What does “CBAM regulation” refer to in the EU?

A: Regulation (EU) 2023/956, as amended in 2025 to simplify and strengthen the system (including a 50‑tonne threshold and first surrender in 2027 for 2026 imports). 

Q: Which sectors does EU CBAM cover today?

A: Cement, iron & steel, aluminium, fertilisers, electricity, hydrogen: defined via CN codes (including some downstream steel/aluminium products). 

Q: When do costs start in the EU?

A: For 2026 imports, with declaration and certificate surrender by 30 Sept 2027. Reporting‑only ran from Oct 2023 to Dec 2025. 

Q: How is the EU CBAM price set?

A: The EU CBAM Price is linked to the average weekly EU ETS auction price (€/tCO₂). The UK is currently in negotiations with the EU to link the ETS price system between the two policies. 

Q: Can I deduct a carbon tax already paid abroad?

A: Yes, explicit carbon prices paid in the country of origin can be credited if properly documented under an equivalent policy. 

Q: What does “UK CBAM” mean in practice?

A: From 1 Jan 2027, the UK will impose a UK CBAM on specified imports in aluminium, cement, fertilisers, hydrogen, iron & steel. It covers direct, indirect and selected precursor emissions, uses actuals or defaults and credits explicit foreign carbon prices. Electricity is out of scope at launch. 

Q: Will EU-UK ETS linkage remove EU CBAM for UK goods?

A: If concluded, linkage can exempt UK–EU trade from CBAM in covered sectors due to aligned carbon pricing. Talks are officially underway and are set to conclude before the introduction of UK CBAM in 2027.

Q: Does the US have a CBAM?

A: No. Several bills (PROVE IT Act, Clean Competition Act, Foreign Pollution Fee Act) are proposals at varying stages. None is law today, and bipartisan support is not consistent with any one policy. 

Q: Is CBAM WTO‑compliant?

A: The EU says yes; some trading partners disagree. A WTO dispute was initiated by Russia in 2025. Expect litigation and guidance over time as the policy evolves.