Carbon Capture and Utilisation (CCU): a vital tool for the rapid decarbonisation of industries and societies.
Carbon capture and utilisation is simultaneously a method of capturing the excess CO2 from our atmosphere as well as maximising the value of the CO2 and therefore initiating the circularisation of the CO2 economy.
At current rates of emission, projection models estimate that global average temperature by the end of the century may be superior to 2°C which will result in serious climate catastrophes, irreversible effects on our ecosystems and consequent impact on vast populations, economies and societies around our planet.
CO2 emissions are the crux of many of the aforementioned issues. For these reasons, it is imperative that we find ways of capturing this CO2 and when possible; utilising this CO2 to mitigate the costs of this operation.
Carbon Capture and Utilisation is comprised of two steps:
- Capturing the CO2 via a wide range of different adsorbent technologies.
- Harnessing the CO2’s potential to convert into a variety of products
Pre-, Post- and Oxy-fuel combustion capturing processes
There are a number of methods in which CO2 can be captured:
- Pre-combustion processes: comprises of converting fuel into a mixture of CO2 and hydrogen. The hydrogen is then separated and combusted without producing any CO2. This CO2 can then be compressed and used in transport and storage.
- Post-combustion processes: separating the CO2 from post-combustion gases. CO2 can then be captured by using liquid absorbents. Once filtered from the exhaust gases, the CO2 is then reheated to form a high purity CO2
- Oxy-Fuel processes: This time, the exhaust gases are mainly water vapour and CO2 as a result of conducting the combustion process with a mix of pure oxygen and CO2 instead of using ambient “air”. This facilitates the separation step.
CO2 as a feedstock for chemicals
CO2 has found success as a building block in polymerisation reactions that form a wide range of synthetic materials. These materials range from simple plastics to foams and even resin. The CO2 can represent up to 50% of the weight of these polymers. The EU polymer market is saturated with fossil fuel carbon sources, and thus needs to change to cleaner options such as CO2 recycling.
CO2 as a feedstock for fuels
As the EU is incentivising the production and consumption of clean fuels, it is also increasing the importance of the organic building block for many of these fuels: methanol. When carbon dioxide is hydrogenated it forms methanol. With this methanol, many more simple carbon-based fuels can be formed such as synthetic methane and ethanol.
Source: ‘Gaseous Carbon Waste Streams Utilization’ National Academic Press, 2019
CO2 as a building block for construction
As infrastructure and urbanisation in the EU develops, construction represents 12% of EU CO2 emissions. Industry and academia have joined efforts to alleviate the environmental pressure of concrete production. One current use of CO2 in the construction industry is called concrete curing.
The carbonation of CO2 to produce solid calcium carbonate (CaCO3) can replace traditionally energy intensive steam-based concrete curing methods. Despite the CO2 representing a low percentage of the concrete’s weight, this process offers the intrinsic long-term sequestration of CO2.
In efforts to increase the percentage weight of CO2 in concrete, researchers and companies are looking to develop cements which use CO2 as an ingredient. Although some of these technologies still require further development, the general consensus is that CCU technologies will play a key-role to a long-term sustainable energy transition.
The driving forces for these technologies are that CO2 needs to be removed from our atmosphere and that a real market value for these emissions needs to be created in order to create a circular economy for CO2. Current estimates of the global CO2 market will soon become a trillion dollar market.
To ensure that we make the best use of these decarbonising and much-needed technologies for our energy transition, Energy Technologies Europe promotes legislation that appropriately recognises all the benefits of CCU technologies.
 Alberici S. Assessing The Potential Of CO2 Utilisation In The UK. Ecofys UK; 2017.
 World Economic Forum https://www.weforum.org/agenda/2020/01/co2-as-industrial-feedstock/