How to Measure Carbon Intensity: A Step-by-Step Guide (With Cement CI Examples)

Carbon intensity (CI) used to be an obscure metric that industry insiders used to "Fight climate change," "Hit net-zero goals," and "Build a more sustainable future."

Now, CI shows up in procurement contracts, compliance filings, and investment memos. This is a positive development if the CI is credible, which can only happen when the methodology used to determine the CI number is solid.

In this guide, we give you a practical, step-by-step framework to measure CI, using cement to show how the same product can produce different scores based on the production process.

Why Measuring Carbon Intensity Correctly Matters

Carbon intensity, which measures GHG emissions per unit of output, is now a trade metric, a compliance metric, and an investment metric.

While most commodities producers need to account for CI, cement is one of the primary targets because it sits squarely in the crosshairs of climate policy and supply chain scrutiny.

For example, two cement facilities can produce identical products but report wildly different CI scores. Why? Because CI scores vary based on how each producer defines their system boundary, which emissions factors they apply, and how they handle allocation.

For cement specifically, CI scores also depend on clinker content, kiln technology, fuel mix, and whether low-carbon innovations like alternative fuels or CCS are in place.

Put simply, production choices determine who faces CBAM certificate costs, who wins low-carbon procurement contracts, and how transition risk is assessed by investors.

The Carbon Intensity Formula Explained

The carbon intensity formula is simple:

Carbon Intensity = Total Greenhouse Gas Emissions / Unit of Output or Activity

The numerator covers total GHG emissions expressed in CO2e (carbon dioxide equivalent), a unit that converts methane, nitrous oxide, and other greenhouse gases into a common measure based on global warming potential.

The denominator is the sector-relevant output unit. For cement and other commodities, the standard is tCO2e per tonne of product. For fuels, it's gCO2e/MJ. For corporate reporting, it's tCO2e per dollar of revenue or per unit of production.

While the formula is easy to remember and use, the inputs are complex. The challenge is defining what counts as an “emission” and what counts as an “output."

How to Measure Carbon Intensity: Step by Step

To measure carbon intensity, you must make a series of methodological decisions, each of which can shift your final score. Here's how you should approach the process.

Step 1: Define Your System Boundary

First, understand the three main scopes:

• Scope 1: Direct emissions from combustion and production processes
• Scope 2: Indirect emissions from purchased electricity
• Scope 3: Upstream supply chain and downstream end-use emissions

For cement, Sylvera uses a cradle-to-gate boundary, which covers raw material extraction and transport, clinker production (the dominant emissions source), cement grinding, and low-carbon innovations such as alternative fuels, carbon capture (CCS/CCUS), and supplementary cementitious materials (SCMs), when applicable. End-use is excluded.

Your boundary choice is incredibly important. For example, a grinding-only facility that sources clinker from a different location may appear to be lower-emission if it excludes upstream clinker emissions, but that comparison is meaningless.

Sylvera's framework attributes upstream clinker emissions to the cement output regardless of where production occurs. This process ensures like-for-like comparison across facility types.

Key frameworks that govern our process include ISO 14040, 14044, and 14067, which define LCA methodology. We also adhere to all CBAM requirements, as CBAM is the primary compliance driver for cement and leads to more sustainable practices.

Step 2: Select Your Output Unit

As mentioned above, the standard output unit for commodities, cement included, is tCO2e per tonne of product. By using standard output units, you normalize comparisons across facilities.

Unit choice also matters when comparing across sectors or schemes. Expressing emissions intensity per unit of activity keeps comparisons honest, but only if the unit is consistent.

Comparing a facility measured in tCO2e/tonne to one measured in kgCO2e/tonne requires conversion, and energy density differences can distort the results.

Step 3: Gather Emissions Data and Apply Emissions Factors

Emissions factors convert activity data, like kilowatt hours of electricity consumed and litres of fuel burned, into GHG emissions estimates. For cement, the key data inputs are:

• Cement Type and Clinker Content: The single biggest driver of cement CI
• Kiln Type: Dry, semi-dry, and wet kilns carry different emission factors
• Fuel Mix: This includes alternative fuel usage, and
• Electricity Consumption: Used for grinding, combined with country-specific grid emission factors

Sources of emissions factors include IPCC default values, national GHG inventories, industry databases, measured and metered data, and regional grid factors.

At Sylvera, we combine the GEM Global Cement and Concrete Tracker with data from facility websites, Environmental Product Declarations (EPDs), and other sources, cross-referenced against EcoInvent 3.11 and peer-reviewed literature. We also use IPCC 2021 GWP100 as the LCIA method.

Measured, facility-level data is always preferable to generic defaults. After all, using measured data instead of IPCC defaults can shift CI results by 30-50% or more. In a compliance context, that difference has a direct financial cost.

This is why data quality is the most critical variable in any  CI assessment. Sylvera's approach includes a confidence score, rated from Very High to Very Low, that directly reflects data quality, aggregating across facility data reliability, completeness for key emission drivers, and emissions factor quality.

Step 4: Account for Co-Products and Allocation

Many production processes generate multiple outputs, and cement production is no exception. How do you split total lifecycle emissions across co-products?

Common approaches include energy allocation, which splits emissions by energy content; mass allocation, which splits emissions by weight; economic allocation, which splits emissions by market value; and displacement, which credits the primary product for replacing a conventional alternative.

Different regulatory schemes mandate different approaches, and switching methods mid-comparison produces misleading results. This is where inconsistency tends to creep in, and one of the reasons why independent, standardized assessments are essential.

Step 5: Calculate, Normalize, and Compare

Finally, sum lifecycle emissions across all stages within your defined boundary. Next, divide by the output unit to get your CI score. Then, normalize your result against relevant benchmarks, such as sector averages, CBAM thresholds, and the facility's peer group.

Remember: An isolated CI number won't tell you very much. What's the boundary? What's the benchmark? What's the methodology? Context is everything.

How Is the Carbon Intensity of Cement Calculated? Worked Examples

These examples show how and why CI varies across cement facilities.

Example 1: Integrated Facility, Dry Kiln, Standard OPC

A large, integrated cement plant produces Ordinary Portland Cement (OPC) through a dry kiln process. Emission sources span raw material extraction, calcination, fuel combustion, and electricity.

OPC has the highest clinker share of any cement type, and clinker content is the single biggest driver of cement CI. This facility represents the high end of the emissions intensity spectrum.

At Sylvera, when no cement type data is available, we default to OPC with a "Very Low" confidence score. This reflects the uncertainty felt by a lack of facility-specific information.

Example 2: Integrated Facility with Alternative Fuels and SCMs

This facility looks similar to the one above, but there are two key differences.

First, the facility substitutes some conventional fossil fuels for alternative or waste-derived fuels. Doing so lowers combustion emissions and thus the total carbon footprint.

Second, the facility uses supplementary cementitious materials (SCMs), like fly ash and slag, to reduce clinker share. This minimizes the clinker fraction and therefore calcination emissions, which are chemical, not combustion-related, and can't be reduced via energy efficiency improvements.

The combination of fuel switching and clinker substitution can materially lower CI without CCS. Sylvera's framework captures both levers at the facility level.

These variations are why categorical labels like "blended cement" are misleading. Two blended cements can carry different CI scores depending on clinker share, fuel mix, and SCM type.

Example 3: Grinding-Only Facility

Another facility purchases clinker from an alternate location and grinds it into cement.

This facility's on-site emissions are limited to electricity consumption for grinding, but upstream clinker emissions still exist and must be attributed to the cement output.

Sylvera handles this by inferring clinker share from the reported cement type using EN 197-1 classifications. We then calculate clinker emissions using country- or region-specific emission factors, and model electricity using global average grinding intensity and country-specific grid factors.

As you can see, grinding-only facilities do not significantly reduce carbon intensity—at least, not on their own. Their CI depends on the carbon intensity of the clinker they source and the emissions intensity of their local electricity grid. Lower energy consumption in these areas leads to a low carbon intensity value for the grinding facility.

Consistent attribution of upstream emissions is essential. Without it, a grinding-only facility can look clean because its boundary is narrow, not because its overall carbon footprint is small.

Common Pitfalls in Carbon Intensity Measurement

Avoid these mistakes when considering how to measure carbon intensity:

• Boundary Manipulation. Narrowing the system boundary to exclude high-emission stages, such as upstream clinker production emissions for a grinding facility, produces artificially low CI scores.
• Default Data Over Measured Data.Using generic emissions factors when facility-specific data is available (or available but inconvenient) skews results. In a CBAM context, this is more than a methodological weakness. It's a full-blown financial liability.
• Inconsistent Allocation. Switching allocation methods mid-comparison creates false comparisons. The same goes for using economic allocation when the relevant compliance scheme mandates energy allocation. Both mistakes allow producers to say they reduce carbon emissions without actually improving environmental performance.
• Ignoring Temporal Factors. Annual-average grid emissions can differ from marginal grid emissions during actual production hours. This fact is especially relevant for facilities with high electricity consumption, where the carbon intensity of electricity generation varies significantly depending on how much their renewable energy sources contribute to the grid.
• Cherry-Picking Benchmarks. Comparing against an unfavorable baseline to make emission reductions look larger than they are. Fortunately, this tactic is getting easier to spot.

At the end of the day, an independent, standardized assessment is the most reliable way to catch these issues before they undermine a procurement decision or compliance claim.

How Carbon Intensity Measurement Is Used in Practice

CBAM. Cement is one of the first sectors covered by the EU Carbon Border Adjustment Mechanism. Embedded carbon intensity determines how many CBAM certificates an importer must purchase, which makes facility-level CI data a direct financial input for traders, buyers, and compliance teams..

Procurement decisions. Buyers across commodities often compare suppliers using verified CI data. For cement, CI variation spans a factor of 40 across global facilities. This spread makes standardized measurement essential for any meaningful comparison.

Investment due diligence. ESG investors and climate finance funds use CI benchmarking to identify best-in-class performers and assess transition risk in commodity-intensive supply chains.

Where Sylvera Stands

Sylvera operates as the independent assessment and data platform for carbon and commodities.

Our Carbon Intensity Assessment delivers independent, facility-level CI assessments for cement, hydrogen, ammonia, and other commodities, using a standardized, mechanism-agnostic methodology that enables like-for-like comparison across suppliers and production pathways.

Our Mechanism Eligibility and Value assessments provide bespoke guidance across CBAM, EACs, EU ETS and more.  This helps producers navigate compliance and voluntary scheme complexity and to maximise the value of their carbon-differentiated product

Our Commodity Insights product offers market and supplier CI intelligence to answer questions like, "Who’s cleaner?" and "What methodologies do they use to achieve a lower CI?" and "Where are they located?" This analysis supports procurement strategies, competitive positioning, and policy compliance.

Want to explore CI data across 500+ facilities globally? Sign up forSylvera's free platform. Need more information? Request a demo to see how carbon intensity data supports decision-grade benchmarking.