CBAM for Cement Importers: Clinker and Cement Guide

CN code 2523 covers hydraulic cements and cement clinker. This includes cement clinker (2523.10), Portland cement (2523.21 and 2523.29), aluminous cement (2523.30), and other hydraulic cements (2523.90). All imports under this heading are in scope for UK CBAM. There are no sub-classification exemptions — every type of hydraulic cement is covered.

Cement clinker is the intermediate product produced by heating limestone and clay in a kiln. It is then ground with gypsum to produce Portland cement. Importers of clinker (2523.10) have CBAM obligations just as importers of finished cement do. The clinker production step accounts for approximately 90-95% of the embedded emissions of the finished cement.

The scope also covers special cements such as white cement, sulphate-resisting cement, and low-heat cement, provided they fall under CN 2523. Blended cements containing fly ash or ground granulated blast-furnace slag (GGBS) are also covered, although the emissions intensity varies significantly with the replacement level.

Cement clinker is both a CBAM-covered product in its own right and a precursor for finished cement. If you import cement, the clinker emissions are embedded in the finished product. If you import clinker and grind it to produce cement in the UK, you import the clinker and the clinker's emissions are what you must report.

A critical concept in cement CBAM is calcination emissions. When limestone (calcium carbonate) is heated in the kiln, it releases CO2 as a chemical by-product of the calcination reaction. These process emissions are separate from the fuel combustion emissions of the kiln and typically account for approximately 60% of total cement production emissions. The remaining 40% comes from fuel combustion to heat the kiln.

Cement emissions intensity varies significantly by production route. Modern dry-process kilns with pre-heaters and pre-calciners have emissions of approximately 600-700 kg CO2e per tonne of clinker. Older wet-process kilns can exceed 900 kg. The use of alternative fuels (waste, biomass) and clinker substitutes (fly ash, slag) can reduce the overall emissions of the finished cement product.

When requesting CBAM data from your cement or clinker supplier, ask for: total embedded emissions per tonne of cement or clinker (kg CO2e per tonne), split into calcination process emissions and fuel combustion emissions. Request the kiln type (dry process with pre-heater, wet process, etc.), the proportion of alternative fuels used, and whether any carbon price has been paid in the country of production.

For cement (as opposed to clinker), ask for the clinker factor — the proportion of clinker in the finished cement. A CEM I Portland cement has a clinker factor of approximately 95%. A CEM II/A-V fly ash cement has a clinker factor of approximately 80%. The clinker factor directly determines the embedded emissions because the clinker is the source of virtually all emissions in cement.

Oremly's cement importer module handles cement and clinker imports automatically. It identifies imports under CN 2523, requests the right data (including clinker factor for cement products), and calculates embedded emissions using the correct methodology for the cement sector, including the calcination process emissions component.