CBAM supplier data · CN 2523
UK CBAM for cement importers
From 1 January 2027, UK CBAM puts a price on the carbon embedded in imported portland and blended cement. According to HMRC's CBAM policy summary, importers can report the actual embedded emissions of those goods or use government default values. Default values are not specific to your supplier's plant. The real figure comes from that plant.
Where the carbon in portland and blended cement comes from
Most cement emissions come from making clinker: limestone releases CO₂ when heated, and the kiln burns fuel. EU CBAM also counts indirect emissions from electricity for cement.
Inputs whose data you need, by carbon impact
These are the goods, precursors and inputs that carry emissions into portland and blended cement under CBAM. Impact bands are qualitative and vary by plant, production route and power source.
Limestone & chalk
Very high impactHeating limestone releases process CO₂ in the kiln. This is usually the largest single source in cement, counted at the clinker plant rather than the quarry.
Data to request: From the plant: clinker output and raw-meal chemistry (CaO and MgO content), so calcination emissions can be calculated.
Clinker
Very high impactThe kiln's output and the reason cement is carbon-intensive. As a precursor, bought-in clinker carries its embedded emissions into the cement.
Data to request: Made on site: the kiln data. Bought in: the clinker supplier's embedded emissions per tonne.
Coal & petcoke
High impactBurned in the kiln. The second large source after calcination.
Data to request: Fuel types and quantities for the period, with calorific values and carbon content.
Portland & blended cement
High impactThe imported CBAM good. Its emissions depend mostly on the clinker-to-cement ratio.
Data to request: Cement produced, clinker consumed, grinding electricity, and embedded emissions per tonne.
Electricity
Varies with power sourceRuns raw-meal grinding, the kiln and the cement mills. Its emissions depend entirely on the grid or captive plant.
Data to request: Electricity per tonne and its source: grid country, or captive plant details.
Alternative fuels
Medium impactWaste-derived fuels and biomass. The biomass share counts as zero; the fossil share counts.
Data to request: Quantities and the biomass fraction, with how it was determined.
Clay, shale & correctives
Low impactAdjust the raw meal's chemistry. Small emissions.
Data to request: Covered by raw-meal data.
Not counted, or counted as zero, under CBAM: gypsum, blast-furnace slag (GGBS), fly ash. You do not need their emissions data for the CBAM return, though quantities can explain a product's figure.
Suppliers to contact, and what to ask
The plant that made the goods holds most of the data. Some inputs come from other companies you may need to reach through it.
| Supplier type | What they supply | What to ask for |
|---|---|---|
| Quarry operators | Often the cement company's own quarry, supplying limestone, chalk and clay. | Usually no separate request; quantities appear in the plant's raw-meal data. |
| Coal & petcoke traders | Supply the kiln's fossil fuels. | Fuel specification sheets: carbon content and calorific value per delivery. |
| Waste-fuel processors | Prepare waste-derived and biomass fuels. | Composition analysis showing the biomass fraction. |
| Power utility / captive plant | Grid supplier, or the plant's own power station. | Electricity source and, for a captive plant, its fuel and efficiency. |
| Gypsum suppliers | Mines, or power stations selling flue-gas gypsum. | Not needed for CBAM. |
| Steelworks & slag grinders | Sell ground blast-furnace slag (GGBS). | Quantities only, to explain a low clinker ratio. |
| Fly ash marketers | Sell ash from coal power stations. | Quantities only, to explain a low clinker ratio. |
| Other clinker plants | Supply grinding-only sites that buy clinker rather than make it. | Embedded emissions per tonne of clinker, ideally in the EU CBAM template. |
What to do before 1 January 2027
- 1. Map. List your imported portland and blended cement by supplier and tonnage, and find the plant behind each supplier, not just the trader.
- 2. Request. Ask the 7 supplier types above for the data listed, starting with the suppliers covering most of your tonnage. Accept the EU CBAM template if they already use it.
- 3. Check. Compare each figure with the production route and the default value for that product and country, and send outliers back with a specific question.
- 4. Report. Keep the evidence behind every figure. HMRC says the first UK CBAM return and payment, for 2027, are due by 31 May 2028.
CarbonMeter's CBAM readiness pilots do this with you: we map your imports to the plants that made them, request and check the data, and report embedded emissions per supplier and product with the evidence behind each number.
Questions
Which cement goods does UK CBAM cover?
UK CBAM applies from 1 January 2027 to imported portland and blended cement, commodity codes under CN 2523, according to HMRC's CBAM policy summary. The importer is liable once its CBAM goods pass a £50,000 threshold, and can report the actual embedded emissions of the goods or government default values.
Where does the carbon in portland and blended cement come from?
Most cement emissions come from making clinker: limestone releases CO₂ when heated, and the kiln burns fuel. EU CBAM also counts indirect emissions from electricity for cement.
What should a UK importer ask a cement supplier for?
The data that the plant which made the goods holds: for limestone & chalk, from the plant: clinker output and raw-meal chemistry (CaO and MgO content), so calcination emissions can be calculated.; for clinker, made on site: the kiln data. Bought in: the clinker supplier's embedded emissions per tonne.; for coal & petcoke, fuel types and quantities for the period, with calorific values and carbon content.; for electricity, electricity per tonne and its source: grid country, or captive plant details.. Many producers already report this to EU customers in the European Commission's CBAM template.