Carbon-14 testing offers a reliable method to quantify the biogenic share of CO₂ emissions, enabling compliance with regulatory schemes and supporting emissions monitoring on the road to net-zero.
Cement plants and other industries with extensive greenhouse gas emissions are starting to use carbon capture, utilisation and storage (CCUS) technologies to mitigate their CO₂ emissions. These emissions come from two main processes in the cement production process. Fuel combustion accounts for 35 - 40% of the total CO₂ emissions from cement manufacturing. The process of producing CO₂ from limestone calcination accounts for 60 - 65% of total emissions.
Using 100% biomass-derived fuels would not reduce all of the CO₂ emissions from cement plants, which creates a need to deploy CCUS technologies. It also emphasises the importance of substituting fuels, as decarbonisation schemes increasingly demand emissions reductions to achieve net-zero. Biogenic content testing via carbon-14 analysis is a valuable tool for the cement industry to evaluate emissions reductions and quantify the biogenic CO₂ removals achieved by CCUS.
Carbon-14 applications to the cement industry
Biogenic carbon content testing measures carbon-14, an isotope present in all living organisms. Petrochemical-derived material no longer contains any carbon-14 due to its age, as carbon-14 is lost over time via radioactive decay. Biogenic carbon content test results are reported as a percentage of material produced from renewable feedstocks.2 Carbon-14 testing via accelerator mass spectrometry (AMS), according to the ASTM D6866 and ISO 13833 analytical standards, has increasingly been used in various clean fuels programs and decarbonisation schemes around the world to quantify emissions reductions and improve monitoring rules.
Regulators are increasingly putting pressure on the cement industry to reduce emissions, notably the US Environmental Protection Agency’s Greenhouse Gas Reporting Program (GHGRP) and the EU’s emissions trading system (ETS). Under most decarbonisation schemes, biogenic CO₂ (from sustainable biomass) and fossil CO₂ are treated differently. Hence, operators increasingly need to distinguish how much of that CO₂ comes from fossil sources versus biomass. Biogenic CO₂ is considered ‘carbon-neutral’ and not counted towards the total emissions emitted by cement plants, as it is part of the current carbon cycle, whereas fossil CO₂ adds new carbon to the atmosphere. Carbon-14 testing is the ideal analytical methodology to distinguish between biogenic CO₂ and fossil CO₂; it can accurately determine the biogenic share of emissions and identify the biomass-derived portion of feedstock combusted during the process (Figure 1). Additionally, if a cement plant uses some biomass-based fuels and installs carbon capture systems, it might be eligible for extra credit (or avoided penalties) for the biogenic portion of CO₂ that it’s storing.3 This makes accurate accounting essential.
The growing role of CCUS
CCUS is gaining prominence as a key solution for hard-to-abate industries looking to significantly cut CO₂ emissions. CCUS solutions trap emissions, either by storing them underground or utilising them in products like concrete curing or synthetic fuels.
In scenarios where biomass fuels are used, it could help a cement plant achieve net-negative emissions, as biogenic CO₂ absorbed from the atmosphere would be permanently stored. Therefore, it is essential to accurately determine the source of the CO₂ captured and stored for plants to be considered carbon-neutral or carbon-negative. It is well understood in the CCUS industry that only atmospheric/biogenic carbon capture can be classified as carbon removal, as it is part of the active carbon cycle. Fossil emissions captured and stored cannot be classified as removals. Therefore, if cement plants want to achieve net-zero emissions, determining the share of biogenic CO₂ captured using carbon-14 testing is crucial to quantify the source of the carbon captured and stored.
Several CCUS projects are currently underway in the cement industry, and more are expected to follow with the end of free allowances and reduction of emissions caps.
Additionally, several methodologies have been developed to quantify and credit carbon removals. Many of them, such as Carbon Direct’s 2025 criteria for high-quality carbon dioxide removal, recommend carbon-14 testing to verify biogenic CCUS.
Current regulations
Most emissions reduction programmes apply to cement plants due to their significant emissions impact. Both the US GHGRP4 and Canada’s GHGRP5 programmes require carbon-14 testing for emissions from the combustion of biogenic and waste-derived feedstocks. Canada also requires testing if the fuels combusted contain an unknown biomass fraction. Similarly, the EU ETS requires testing for emissions claiming biogenic content, as well as for any combusted biomass seeking an emissions factor of 0.6. Additionally, the EU carbon border adjustment mechanism (CBAM) requires testing to determine the biogenic portion of the emissions of cement goods produced outside the EU, and for the fuels used in the combustion process.7
A growing number of regulations and methodologies specifically focus on CCUS, such as Alberta’s protocol for carbon capture, which requires carbon-14 testing to obtain carbon removal credits. The EU regulation establishing the framework for permanent carbon removals also specifically requires distinguishing between biogenic and fossil emissions and refers to the EU ETS requirements to do so.8
Conclusion
Carbon-14 analysis is an essential tool for the cement industry to identify how much biogenic carbon versus fossil carbon is emitted and captured and therefore accurately reported. This data is valuable for monitoring carbon neutrality and also ensures compliance with regulations that require such analysis e.g. the US GHGRP and the EU ETS. Biogenic content determination is also valuable to accurately account for carbon removals as part of the CCUS process and help the cement industry achieve its net-zero goal.
References
- Roadmap to a net-zero carbon cement sector: Strategies, innovations and policy imperatives, Journal of Environmental Management, 2024.
- Standard Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis, ASTM International, 2021.
- This is notably the case under Alberta’s protocol for carbon capture: https://open.alberta.ca/publications/quantification-protocol-for-carbon-dioxide-capture-and-permanent-geologic-sequestration
- 40 CFR Part 98 Subpart C – General Stationary Fuel Combustion Sources, National Archives Code of Federal Regulations, 2022.
- Canada’s Greenhouse Gas Quantification Requirements, Environment and Climate Change Canada, 2022.
- Commission Implementing Regulation (EU) 2018/2066, Official Journal of the European Union, 2018.
- Guidance Document on CBAM Implementation for Installation Operators Outside of the EU, European Commission, 2025.
- (Draft), Carbon Removals and Carbon Farming – Methodologies for Certifying Permanent Carbon Removals, European Commission, 2025.
