Captured CO₂ isn't necessarily bound for geological storage. It can also be used directly or serve as a feedstock for making fuels, chemicals, polymers or building materials. This approach, known as CCU (Carbon Capture and Utilisation), opens up another way to manage and add value to the carbon flows coming from industrial activities.
Some forms of CO₂ utilisation are already well established, while others, such as synthetic fuels and carbonated concrete, are still being developed. Their climate benefit, however, varies depending on the process, where the CO₂ comes from and how long the carbon remains locked in the product.
CCS, CCU, CCUS: Three Acronyms. What is their distinction?
Before looking at the products made from captured CO₂, it helps to understand the different pathways for managing it or putting it to work.
What "Using" CO₂ Means
Captured CO₂ can follow two main routes. The first is to use it directly, without any chemical transformation. The second is to convert it into new products.
Direct uses include:
Carbonated beverages and CO₂-enriched agricultural greenhouses that boost plant growth.
Enhanced oil recovery (EOR), in which CO₂ is injected into reservoirs to make oil extraction easier.
The use of supercritical CO₂ as a solvent in certain industrial processes.
Conversion-based uses, for their part, make it possible to produce synthetic fuels, chemicals, building materials and polymers. The ICEF (Innovation for Cool Earth Forum) defines CO₂ utilisation as employing it to produce goods or services with economic value. [3] The IEA also includes within CCU the cases where CO₂ is used, notably to manufacture fuels and chemicals. [1]
CCS vs CCU: Two Complementary Approaches
CCS (Carbon Capture and Storage) refers to capturing CO₂ and then storing it permanently, usually in deep geological formations. The goal is to keep the captured CO₂ out of the atmosphere for the long term. [1]
CCU, by contrast, treats CO₂ as a resource. It can be used directly or converted into marketable products. Depending on the application, the carbon may stay trapped for a long time or return to the atmosphere after use. The term CCUS (Carbon Capture, Utilisation and Storage) covers all approaches involving the capture, use and storage of CO₂.
The rest of this article focuses on the CCU side: the products that CO₂ can actually be turned into and the role these different pathways could play in the energy transition.
An Overview of Products Made from CO₂
Captured CO₂ utilisation is already in place across several industrial sectors. A 2024 analysis published by OGCI (Oil and Gas Climate Initiative) puts global demand at around 250 Mt of CO₂ per year, mainly for urea manufacturing and enhanced oil recovery. [9] Alongside these established uses, several conversion routes allow CO₂ to be incorporated into fuels, chemicals, polymers or building materials.
The Five Main Families of CO₂-Derived Products
CCU applications span several sectors. The IEA groups them into five broad categories: fuels and chemical intermediates, chemicals, building materials from mineralisation, materials produced from industrial waste, and biological uses, particularly in greenhouses. [5] The National Academies also identify several product categories that could support the growth of CCU, including building materials, polymers, fuels and chemicals. Their potential depends on market size, infrastructure requirements and how long the carbon stays embedded in the products. [4]
Table 1: The Five Main Categories of CO₂ Use
| Application family | Example products | Maturity |
|---|---|---|
| Fuels and intermediates | Methanol, methane, aviation fuels | Demonstration to commercialisation depending on process |
| Chemicals | Urea, formic acid, polycarbonates | Established to emerging, depending on product |
| Mineral-based building materials | Carbonated concrete, aggregates | Demonstration to commercialisation |
| Materials from industrial waste | Mineralised aggregates and materials | Demonstration to commercialisation depending on process |
| Biological uses | CO₂-enriched greenhouses | Commercially established for greenhouses |
Sources: [2], [5], [7]
Current Volumes: Two Uses Far Outweigh the Rest
According to a 2024 analysis by OGCI and Boston Consulting Group, global demand for CO₂ across various applications was estimated at roughly 250 Mt per year. Urea production and enhanced oil recovery were the two leading outlets, while newer conversion routes held a more modest share. [9] Several applications are nonetheless under development, notably synthetic fuels, chemicals and CO₂-based building materials. [2]
Growth prospects differ by technology and by the scenarios considered. One analysis published in 2024 estimates that global CO₂ use could reach approximately 430 to 840 Mt per year by 2040. [9] This range reflects, among other things, the uncertainty surrounding the commercial development of the various sectors and the share of captured CO₂ that will be put to use rather than stored.
Three Emerging CCU Pathways
Beyond the industrial uses already established, several CO₂ utilisation routes are the focus of research and commercial projects. Among them, synthetic fuels, carbonated building materials and CO₂-based polymers illustrate three distinct approaches. They differ as much in their conversion processes as in how long the carbon remains locked in the final product.
Synthetic Fuels (e-fuels / Power-to-X)
CO₂ can serve as a feedstock for several energy-carrying molecules, including methane, methanol and certain aviation fuels. [2] These processes generally rely on combining CO₂ with hydrogen, ideally produced from low-emission electricity.
The thermochemical routes under study include:
Direct CO₂ hydrogenation, particularly for producing methanol.
Indirect conversion via RWGS (Reverse Water-Gas Shift), which yields carbon monoxide that can then be used to synthesise fuels or chemical intermediates.
Other thermocatalytic reactions, capable of producing formic acid or more complex molecules, including certain hydrocarbons from Fischer-Tropsch processes. [6]
In these applications, CO₂ supplies the carbon needed to build energy molecules from hydrogen, notably liquid or gaseous fuels that can be easier to store, transport and use within some existing infrastructure. [2]
Carbonated Concrete: Mineralising CO₂ in Materials
In construction, captured CO₂ can be used to form solid carbonates within certain materials. There are two main approaches:
Injection into fresh concrete during mixing.
CO₂ curing, where precast elements are exposed to a CO₂-enriched atmosphere. [7]
The CO₂ then reacts with certain compounds in the concrete to form solid carbonates, including calcium carbonate (CaCO₃). Part of the carbon is thus held within the material over long periods.
Mineralisation stands out above all for its potential for durable carbon storage. The National Academies classify carbonated concrete and aggregates as Track 1 products, defined by a lifespan of more than 100 years and the ability to retain carbon over the long term. [4]
The ICEF, for its part, identifies cement and aggregates among the key near-term markets for CCU, owing in particular to the enormous volumes of materials consumed by the construction sector and the stability of the resulting carbonates. [3]
CO₂-Based Polymers and Chemicals
Polymer and chemical manufacturing offers another avenue for putting captured CO₂ to use. In some industrial processes, CO₂ can replace a portion of fossil feedstocks and help produce components found in plastics, resins, foams and other materials. [5]
Although some processes are already in commercial operation, CO₂ utilisation in the chemical industry remains an emerging field at large scale. Its growth depends in part on improved conversion technologies, access to raw materials and the adaptation of production infrastructure.
Over the longer term, these advances could help diversify the carbon sources that industry relies on. In one scenario examined by the National Academies, CO₂ could supply about 25% of carbon demand for chemicals and derived materials by 2050. This outlook nonetheless hinges on developing the necessary technologies and supply chains. [8]
Molecules that can be produced from CO₂ can be grouped by the number of carbon atoms they contain:
C1 products, containing a single carbon atom: methanol (CH₃OH), methane (CH₄), carbon monoxide (CO), formic acid (HCOOH) and urea.
C2+ products, containing two or more carbon atoms: certain alcohols, carboxylic acids, hydrocarbons and other more complex molecules. [6]
Table 2: Three CCU Pathways: Mechanism, Products and Carbon Permanence
| Pathway | Main mechanism | Key products | Carbon permanence |
|---|---|---|---|
| Synthetic fuels | Conversion of CO₂ with hydrogen | Methanol, methane, aviation fuels | Short, Track 2 products |
| Carbonated concrete | Mineralisation into carbonates | Concrete, aggregates | Potentially durable, Track 1 products |
| Polymers and chemicals | Chemical synthesis | Plastics, resins, chemical intermediates | Variable |
Sources: [2], [4], [7]
From Capture to Carbon Utilisation
Captured CO₂ utilisation opens up new prospects for the chemical, energy and materials sectors. By turning CO₂ into a raw material, CCU makes it possible to explore new production routes and broaden the range of carbon sources available to industry.
While the climate benefits depend on the process, the energy resources involved and how long the carbon is retained, technological progress could pave the way for new industrial applications.
As these sectors mature, CCU could contribute to a more diversified use of carbon resources, complementing emission reduction efforts and geological CO₂ storage solutions.
Follow Squatex on LinkedIn to stay up to date on developments in clean energy and natural resources.
References
[1] International Energy Agency. "About CCUS." IEA, 7 Apr. 2021, https://www.iea.org/reports/about-ccus.
[2] International Energy Agency. Putting CO₂ to Use: Creating Value from Emissions. IEA, 25 Sept. 2019, https://www.iea.org/reports/putting-co2-to-use.
[3] Sandalow, David, et al. Carbon Dioxide Utilization (CO₂U): ICEF Roadmap 2.0. Innovation for Cool Earth Forum, Nov. 2017, https://icef.go.jp/wp-content/themes/icef_new/pdf/roadmap/icef2017_roadmap1.pdf.
[4] National Academies of Sciences, Engineering, and Medicine. Carbon Dioxide Utilization Markets and Infrastructure: Status and Opportunities: A First Report. National Academies Press, 2023, https://nap.nationalacademies.org/read/26703/chapter/2.
[5] International Energy Agency. Putting CO₂ to Use: Creating Value from Emissions. IEA, Sept. 2019, https://iea.blob.core.windows.net/assets/50652405-26db-4c41-82dc-c23657893059/Putting_CO2_to_Use.pdf.
[6] National Academies of Sciences, Engineering, and Medicine. "Chemical CO₂ Conversion to Fuels, Chemicals, and Polymers." Carbon Utilization Infrastructure, Markets, and Research and Development: A Final Report, National Academies Press, 2024, https://www.nationalacademies.org/read/27732/chapter/9.
[7] Rocky Mountain Institute. "Carbon as a Service: Sequestering CO₂ in Concrete." Concrete Solutions Guide, RMI, 2021, https://rmi.org/app/uploads/2021/08/ConcreteGuide5.pdf.
[8] National Academies of Sciences, Engineering, and Medicine. "Priority Opportunities for CO₂- or Coal Waste–Derived Products in a Net-Zero Emissions Future." Carbon Utilization Infrastructure, Markets, and Research and Development: A Final Report, National Academies Press, 2024, https://www.nationalacademies.org/read/27732/chapter/4.
[9] Oil and Gas Climate Initiative, with Boston Consulting Group. Carbon Capture and Utilization as a Decarbonization Lever. Oil and Gas Climate Initiative, Apr. 2024, https://www.ogci.com/wp-content/uploads/2024/05/CCU-Report-vf.pdf.
