Carbon dioxide (CO2) levels in our atmosphere have been almost doubling from its pre-industrial level to reach approximately 426 ppm in January 2025 [1]. This is a concerning situation, considering this gas is the leading contributor to global warming, which results in more frequent and severe weather conditions. In response, global initiatives such as the Paris Agreement in 2016 were launched as joint efforts between countries to reduce their carbon dioxide emissions to limit the surface temperature increases of 1.5°C by the end of the century. However, despite the efforts, the global temperature had already increased by 1.3°C in 2023. The experts predict that by only abiding the 2030 climate target, the temperatures would be increased by 2.6°C by the end of the century [2]. Therefore, significant efforts are still required to prevent further warming of the earth. And one of the main pillars for tackling these issues is the improvement in the carbon capture sector.
Carbon capture refers to the process of capturing CO2 emissions from various point sources to prevent their release into the atmosphere. However, it’s important to note that not all CO₂ emissions are the same. There are two main types: fossil CO2 and biogenic CO2. Fossil CO2 is the major contributor to current atmospheric emissions because it originates from carbon that has been stored underground for millions of years. When released, it increases the overall carbon concentration in the atmosphere. This type of CO2 is primarily emitted through the combustion of fossil fuels used in industrial processes such as ammonia production, steelmaking, plastic productions, cement manufacturing, and energy generation. The CO2 emissions for energy use alone account for approximately 75% of total Green House Gas (GHG) emissions in Europe, amounting to 2.4 gigaton emissions in 2022 [3].
On the other hand, Biogenic CO2 is part of short carbon cycles (typically up to hundred years), which are firstly absorbed by plants as they grow and will be then release back to the atmosphere from biomass decomposition and processing. This type of CO2 did not add to the burden of CO2 in the atmosphere and thus can be characterised as carbon neutral. In addition to fossil CO2 sources, biogenic CO2 also represents an important and more sustainable supply option. In Europe, approximately 506.7 Mt of biogenic CO2 is generated annually from various processes. The majority originates from solid biofuel combustion, which accounts for around 86% of the total, followed by biogas combustion at approximately 11%. The remaining 3% comes from sources such as biogas upgrading and the fermentation processes used in wine and beer production [5].
Both types of CO₂ can be distinguished using radiocarbon dating, a method based on detecting the radioactive carbon isotope ¹⁴C, which is naturally produced in small amount by cosmic rays. A nitrogen atom ¹⁴N absorbs a neutron after which emits a proton and the carbon ¹⁴C is formed and enters the biogenic cycle. Because ¹⁴C is unstable and has a half-life of approximately 5,730 years, it can only be detected in materials up to around 50,000 years old [6]. This makes it possible to differentiate between biogenic CO₂, which contains detectable levels of ¹⁴C, and fossil CO₂, which has no/negligible remaining ¹⁴C, due to its million’s year age [7]. Because fossil fuel has no carbon-14 and biogenic has is possible to establish the fossil carbon percentage is different streams.