10 New EU Guides for CBAM Compliance: What Businesses Need to Know

The European Commission has published a new series of ten guidance documents designed to support businesses with CBAM compliance during the Carbon Border Adjustment Mechanism’s definitive period.

Published on 14^th August 2026, the guidance is particularly relevant to operators outside the EU producing goods covered by CBAM, alongside authorised CBAM declarants and verifiers involved in the compliance process. It provides significantly more detail than previously issued information on areas including emissions monitoring, embedded emissions calculations, CBAM certificates and sector-specific requirements.

For both businesses that manufacture goods outside the EU (installation operators) and businesses that import goods into the EU from non-EU countries (importers), the guidance provides an important opportunity to review whether current/previously developed data collection and reporting processes are ready for the requirements now in force during the definitive period.

Why Has the EU Published New CBAM Guidance?

The CBAM definitive period began on 1^st January 2026, moving the mechanism beyond the transitional reporting stage and introducing more rigorous monitoring, reporting and financial obligations for importers of carbon-intensive goods into the EU.

CBAM currently covers six key sectors:

• Cement
• Aluminium
• Fertilisers
• Iron and steel
• Hydrogen
• Electricity

EU importers (typically EU companies), or their indirect customs representatives, importing more than the applicable 50-tonne threshold of CBAM goods must become authorised CBAM declarants. Under Delivered at Place (DAP) arrangements, the EU customer typically completes the import custo1ms clearance and is therefore usually the importer responsible for CBAM. However, the customs declaration and representation arrangements ultimately determine responsibility. Authorised declarants must purchase and surrender the required CBAM certificates.

The new EU CBAM guidance is intended to make the practical requirements clearer, particularly for non-EU installation operators responsible for supplying the emissions information that EU importers need. For a broader introduction to the Carbon Border Adjustment mechanism, read our insight on how CBAM works and what it means for businesses. 

What Do the 10 CBAM Guidance Documents Cover?

Rather than producing a single extensive guide, the European Commission has divided its new CBAM guidance documents into four general guides and six sector-specific documents.

Guide 1. Introduction to CBAM Concepts

The first guide provides an overview of the CBAM compliance cycle, including the main roles and responsibilities, milestones, deadlines and exemptions relevant to operators outside the EU.

For organisations that are still establishing exactly how CBAM affects their operations or supply chains, this provides a useful starting point.

For further guidance, download our practical guide to CBAM.

Guide 2. Quick Guide for Non-EU Operators

Guidance No. 2 acts as a roadmap for operators of installations producing CBAM goods.

It introduces the main principles of CBAM emissions monitoring and directs businesses towards the more detailed information contained throughout the other guidance documents.

This is particularly relevant because CBAM compliance is not solely an importer responsibility. Importers can only report emissions information when manufacturers and suppliers further up the supply chain have suitable monitoring systems in place.

Guide 3. Calculating Embedded Emissions

One of the most significant documents covers the calculation of CBAM embedded emissions.

The guide explains how installation operators must monitor and calculate emissions under the definitive regime, including emissions associated with relevant precursor materials used to manufacture complex goods. This can require accurate, supplier-specific information throughout the production chain, rather than data relating only to the final manufacturing installation.

The definitive calculation rules differ significantly from those used during the transitional period. Organisations should therefore review and update existing methodologies, as transitional approaches may no longer comply with the definitive requirements.

Accurate data is also important because embedded emissions form the starting point for calculating the CBAM liability, before applying the free allocation adjustment and any eligible deduction for a carbon price already paid.

Guide 4. Free Allocation Adjustment

The fourth general document covers the calculation of the free allocation adjustment.

The adjustment reflects the gradual phase-out of free EU ETS allowances for EU producers as CBAM is phased in between 2026 and 2034. It effectively scales the CBAM liability during this period, so importers initially surrender certificates for only a proportion of the embedded emissions that would otherwise be subject to CBAM.

This proportion increases progressively until 2034, when free allocation for CBAM-covered EU production is fully phased out and the corresponding CBAM liability is fully applied.

The Commission's guidance explains how this adjustment should be calculated using the relevant CBAM benchmarks and annual adjustment factor.

Six Sector-Specific CBAM Guides

The remaining six documents provide dedicated CBAM compliance guidance for each sector currently covered by the mechanism:

• Guidance 5a – Cement
• Guidance 5b – Hydrogen
• Guidance 5c – Fertilisers
• Guidance 5d – Iron and steel
• Guidance 5e – Aluminium
• Guidance 5f – Electricity

Each looks more closely at relevant production processes, value chains and emissions monitoring and reporting considerations, supported by worked examples.

This sector-specific approach is important because determining embedded emissions can differ considerably depending on the materials, precursors and manufacturing processes involved.

Businesses should therefore make sure that their CBAM emissions reporting reflects the requirements applicable to their particular products rather than relying solely on general carbon accounting methods.

Actual Emissions Data Is Becoming Increasingly Important

A central message behind the new guidance is the importance of developing reliable processes for reporting actual emissions.

The European Commission specifically highlights the need for installations to establish appropriate Monitoring Plans and robust monitoring processes and to understand when actual and default values can be used.

Importers may use Commission default values or verified actual emissions when preparing their CBAM declarations. However, default values are deliberately punitive and include a mark-up, which increases from 10% in 2026 to 20% in 2027 and 30% from 2028 onwards, except for fertilisers, where a lower mark-up applies. Where a producer’s actual emissions are below the applicable default, verified data can therefore reduce the number of CBAM certificates that must be surrendered. Actual data also ensures that lower-carbon production processes are properly reflected, including cleaner energy sources, more efficient technologies and lower-emission precursor materials. Accurate supporting information may also be required to claim eligible deductions for carbon prices already paid in the country of production.

Using actual values requires the non-EU producer to provide verified information covering the embedded emissions of both the imported goods and, where applicable, relevant precursor materials. This makes supplier engagement increasingly important.

Businesses may need to work across their supply chains to establish:

• Which products and CN codes fall within CBAM
• Which installations manufacture the relevant goods and their precursors
• What emissions and carbon-price information is available
• Whether monitoring methodologies align with CBAM requirements
• How information will be communicated between operators and EU declarants
• Whether emissions information is sufficiently robust for verification

For organisations with complex international supply chains, establishing these processes may require significantly more work than simply completing a declaration. However, doing so can avoid conservative default values, recognise investments in lower-carbon production and support eligible carbon-price deductions.

What Should Businesses Do Now?

The publication of the new guidance provides a useful opportunity to review existing CBAM compliance arrangements.

Businesses affected by the regulation should consider mapping relevant imports and suppliers, reviewing current embedded emissions calculations and checking whether suppliers have suitable monitoring processes in place.

Particular attention should be given to the differences between transitional reporting and the definitive regime. The Commission specifically identifies changes to embedded emissions calculations, the use of default values and the free allocation adjustment as areas businesses need to understand.

Verification should also be built into preparations. The first CBAM declarations covering 2026 imports are due by 30^th September 2027, alongside the corresponding surrender of CBAM certificates. Where actual emissions values are reported, verified information from producers will form an important part of this process.

Instead of treating CBAM as a one-time compliance report, the goal should be to establish a repeatable data and reporting process to set you up for ongoing reporting.

How Tunley Environmental Can Support CBAM Compliance

Understanding the legislation is only one part of preparing for CBAM. Businesses must also identify affected trade flows, obtain reliable supply-chain data, apply compliant calculation methodologies and establish effective processes between installation operators, suppliers and EU importers. Tunley Environmental provides science-based CBAM support tailored to both non-EU producers and EU importers.

Our services include:

• CBAM awareness and technical training
• Supply-chain, product and CN code mapping
• Assessment of importer, supplier and installation responsibilities
• Supplier engagement and data-collection support
• Installation-level emissions calculations and bespoke CBAM calculators
• Development of Monitoring Plans and calculation methodologies
• Mass-balance, precursor and production-route calculations
• Review of emissions factors, default values and carbon-price information
• Data-quality assessment and preparation for third-party verification
• Ongoing regulatory monitoring and methodology updates

Whether an organisation is developing its CBAM processes for the first time or reviewing methodologies established during the transitional period, we can help identify compliance gaps and implement practical, robust systems for the definitive regime.