Key Takeaways
- What it is: UK CBAM requires importers to pay for the carbon content of certain high-emission goods
- When it starts: Transitional reporting began January 2026, financial obligations start 2027
- Covered goods: Cement, iron & steel, aluminium, fertilisers, electricity, and hydrogen
- Cost impact: Adds £15-85 per tonne of embedded CO₂ equivalent (varies by carbon price)
- Who’s affected: Importers of covered goods from countries without equivalent carbon pricing
- Key requirement: Quarterly CBAM returns and purchase of CBAM certificates
The UK’s Carbon Border Adjustment Mechanism (CBAM) represents the most significant environmental trade policy shift since Brexit. Launched in parallel with the EU’s CBAM system, it fundamentally changes how UK businesses import carbon-intensive goods.
If you import cement, steel, aluminium, or other covered products, this isn’t just another compliance burden—it’s a major operational and financial consideration that requires immediate attention.
What Is UK CBAM and Why Does It Exist?
CBAM is essentially a carbon tariff. It requires UK importers to pay for the carbon emissions embedded in certain goods imported from countries that don’t have equivalent carbon pricing systems.
The mechanism serves two purposes:
- Protect UK businesses: Prevents “carbon leakage” where UK companies face unfair competition from imports produced with cheaper, high-carbon energy
- Global climate action: Incentivises other countries to implement their own carbon pricing or cleaner production methods
Think of it as levelling the playing field. If a UK steel manufacturer pays for carbon emissions through the UK’s carbon pricing systems, importers of foreign steel should face equivalent costs.
How UK CBAM Differs from EU CBAM
While the UK system mirrors many EU CBAM principles, there are crucial differences:
Coverage Scope
- UK CBAM: Initially covers 6 sectors (same as EU), but with different technical specifications
- EU CBAM: Slightly broader coverage of certain product subcategories
Carbon Price Reference
- UK CBAM: Based on UK Emissions Trading Scheme (UK ETS) prices
- EU CBAM: References EU ETS prices
Administrative Process
- UK CBAM: Managed by HMRC through UK CBAM Registry
- EU CBAM: Administered by EU member state authorities
Timeline
- UK: Transitional phase January 2026-December 2026, financial obligations from January 2027
- EU: Similar timeline but with different quarterly reporting deadlines
Critical point: Having EU CBAM compliance doesn’t automatically cover UK requirements. You need separate UK CBAM authorisation and certificates.
Which Goods Are Covered?
UK CBAM applies to imports of specific carbon-intensive products:
1. Cement
- CN codes: 2523.10 to 2523.90
- Coverage: All cement clinkers and hydraulic cements
- Key consideration: Includes blended cements with fly ash or slag
2. Iron and Steel
- CN codes: 7201-7207, 7208-7216, 7217-7229
- Coverage: Raw iron, steel products, finished steel goods
- Key consideration: Some downstream products (like machinery containing steel) may be covered
3. Aluminium
- CN codes: 7601-7606, 7607-7616
- Coverage: Unwrought aluminium, aluminium bars, sheets, tubes
- Key consideration: Includes both primary and secondary (recycled) aluminium
4. Fertilisers
- CN codes: Various codes within 2808, 2814, 2834, 3102-3105
- Coverage: Ammonia, nitric acid, nitrogen/phosphorus/potash fertilisers
- Key consideration: Some compound fertilisers may fall under multiple categories
5. Electricity
- CN codes: 2716.00 (electrical energy)
- Coverage: Direct imports of electricity
- Key consideration: Mainly relevant for Northern Ireland imports from Ireland
6. Hydrogen
- CN codes: 2804.10
- Coverage: Pure hydrogen gas
- Key consideration: Growing sector with significant decarbonisation implications
Understanding Carbon Content and Default Values
Each covered good has embedded carbon calculated in tonnes of CO₂ equivalent per tonne of product. You can use:
Default Emission Values
HMRC publishes default carbon intensity values for each covered product and country of origin. These are conservative estimates that tend to overstate emissions.
Examples of default values (per tonne of product):
- Hot-rolled steel coil: 2.19 tonnes CO₂e
- Cement clinker: 0.88 tonnes CO₂e
- Primary aluminium: 16.78 tonnes CO₂e
Actual Emission Values
You can use lower, verified emission values from the producer if you have:
- Verified emissions data from the installation
- Third-party verification certificates
- Proper documentation chain
Cost impact example: For 100 tonnes of primary aluminium with default emissions (16.78 tonnes CO₂e per tonne), at a carbon price of £50/tonne CO₂e, the CBAM cost would be £83,900.
Compliance Requirements for Importers
1. CBAM Authorisation
Before importing covered goods, you must:
- Register on the UK CBAM Registry (managed by HMRC)
- Obtain a UK CBAM authorisation number
- Provide financial guarantees if required
- Nominate responsible persons for CBAM compliance
2. Quarterly CBAM Returns
You must submit quarterly returns declaring:
- Quantities of covered goods imported
- Country of origin and production installation details
- Embedded carbon content (default or verified values)
- Any carbon price already paid in the country of origin
- CBAM certificates surrendered
Deadlines: Returns due by the last day of the month following each quarter (31 January, 30 April, 31 July, 31 October).
3. CBAM Certificates
For 2027 onwards, you must:
- Purchase CBAM certificates equivalent to the carbon content of your imports
- Account for any carbon price already paid in the country of origin
- Surrender certificates quarterly through your CBAM return
Certificate pricing: Certificates are priced based on the average weekly auction price of UK ETS allowances.
Practical Implementation Steps
Phase 1: Assess Your Exposure (Immediate)
- Audit your imports: Review 2025 import data to identify covered CN codes
- Quantify volumes: Calculate total tonnage of covered goods by origin country
- Estimate costs: Use default emission values and current UK ETS prices for budget planning
- Identify suppliers: Map which production installations supply your covered goods
Phase 2: Establish Compliance Framework (Q2 2026)
- Register for CBAM authorisation through HMRC’s UK CBAM Registry
- Develop data collection processes for gathering emission information from suppliers
- Update supplier contracts to require CBAM-relevant documentation
- Train your customs/procurement teams on CBAM requirements
Phase 3: Optimise Your Approach (Ongoing)
- Work with suppliers to obtain verified (lower) emission values rather than defaults
- Consider supply chain changes to source from countries with carbon pricing systems
- Evaluate carbon credit strategies where applicable
- Monitor regulatory updates as the system expands to cover more sectors
Impact on Your Supply Chain Strategy
CBAM is reshaping global trade patterns. Consider these strategic responses:
Supplier Diversification
- Priority sourcing: Countries with robust carbon pricing (EU, UK, Canada) may become more competitive
- Regional shifting: Increased interest in domestic UK production or near-shoring
- Supplier selection: Factor CBAM costs into total landed cost calculations
Carbon Transparency Requirements
- Data demands: Suppliers must provide detailed emission data or accept default (higher) values
- Verification standards: Third-party emission verification becomes a competitive advantage
- Long-term partnerships: Deeper collaboration needed with suppliers on decarbonisation
Commercial Negotiations
- Price adjustments: CBAM costs typically passed through supply chains
- Contract terms: Include CBAM compliance obligations and data provision requirements
- Risk allocation: Agree who bears the cost of emission default values vs verified data
Common Questions and Practical Answers
Q: What if my supplier can’t provide emission data? You’ll use HMRC’s default values, which are typically higher than actual emissions. This makes getting verified data a commercial priority.
Q: How do I handle goods that transit through multiple countries? CBAM applies based on the country of origin (where the covered good was produced), not transit countries.
Q: What if I import from a country with carbon pricing? You can claim credit for carbon prices already paid in the origin country, reducing your UK CBAM obligation.
Q: Are there any exemptions or thresholds? Currently, no de minimis threshold exists. All imports of covered goods are subject to CBAM regardless of value or volume.
Q: What happens if I don’t comply? HMRC can impose penalties, suspend your CBAM authorisation, or require additional financial guarantees. Civil penalties typically range from £500-£5,000 per violation.
Q: Will CBAM expand to cover more products? Yes, the EU and UK are both reviewing expansion to chemicals, plastics, and other sectors from 2030 onwards.
Integration with Other Trade Measures
CBAM interacts with several existing UK trade mechanisms:
Customs Duties
- CBAM is separate from standard import duties but both apply to covered goods
- Total landed cost includes both standard duty and CBAM charges
- Different preferential duty arrangements don’t affect CBAM obligations
UK Global Tariff (UGT)
- CBAM applies regardless of whether goods enter under preferential or MFN tariff rates
- Trade agreement benefits reduce customs duties but not CBAM charges
Customs Declaration Requirements
- Additional data elements required on customs declarations
- CN code classification becomes even more critical for CBAM coverage determination
- Enhanced record-keeping requirements for CBAM compliance
Preparing for 2027 and Beyond
While 2026 is a transitional reporting-only period, the financial obligations starting in 2027 will be substantial. Early preparation is essential:
Q2 2026: Complete CBAM registration and establish supplier data collection Q3-Q4 2026: Test quarterly reporting processes and refine emission data quality Q1 2027: Begin purchasing and surrendering CBAM certificates for financial compliance
The businesses that treat CBAM as a strategic supply chain consideration—not just a compliance burden—will maintain competitive advantage as carbon costs become a permanent feature of international trade.
Remember, CBAM represents a fundamental shift towards carbon accountability in global commerce. Whether you’re importing steel for construction, cement for infrastructure, or aluminium for manufacturing, understanding and optimising for CBAM is now essential for sustainable UK operations.
Key Resources
- UK CBAM Registry: gov.uk/guidance/uk-carbon-border-adjustment-mechanism
- HMRC CBAM Guidance: Updated quarterly with technical specifications
- UK ETS Auction Results: For current certificate pricing references
- CN Code Classification: Use the UK commodity codes guide for accurate product classification