What is CO2 Utilization?
Carbon dioxide utilization refers to using or repurposing CO2 that has been captured using Direct Air Capture or point source carbon capture. It is an alternative to sequestering the captured CO2 in depleted oil wells or with geological mineralisation.
By utilizing CO2 and repurposing it into products and processes, we address, in part, the alarming levels of carbon dioxide in the atmosphere that are causing climate change.
Value of Carbon Utilization
Utilizing CO2 that has been captured can lower the costs of reducing emissions by turning waste into revenue-generating products.
We use approximately 230 million tonnes (Mt) of carbon dioxide annually in a number of processes. The largest consumer is the fertiliser industry where 130Mt of CO2 is used, followed by the oil and gas industry at 80Mt for Enhanced Oil Recovery (EOR).
Currently, the CO2 used is produced in synthesis gas plants such as ammonia/ hydrogen production, in breweries through the fermentation process, or through burning fossil fuels such as natural gas. So instead, we can use CO2 captured in a more environmentally friendly way.
Where Utilization of CO2 can be Employed
The most promising areas of CO2 usage are:
Hydrocarbon Fuels
Combining hydrogen with CO2 can produce hydrocarbon fuels and replace fossil fuels for high energy applications e.g. shipping, heavy duty vehicles and aviation. However, for these fuels to be economically viable and carbon neutral, we need a cheap and environmentally safe source of hydrogen.
Grey hydrogen is produced with coal or lignite gasification and is a carbon-intensive processes.
Blue Hydrogen is produced via natural gas or coal gasification but the CO2 emitted is captured at the source using carbon capture and storage (CCS) technologies.
Green hydrogen is produced using electrolysis of water with electricity generated by renewable energy. It can only be considered truly green if the electricity used is from a carbon-neutral source.
Sustainable Aviation Fuel (SAF)
Aviation is a major culprit of CO2 emissions and this industry is under intense pressure to reduce the fossil fuel component of its fuels. For example, the EU is mandating the increased use of SAF at airports (2% by 2025 and 70% by 2050). In this context, sustainable aviation fuel (SAF) offers a solution for the future of aviation as a greener and more viable industry.
The captured CO2 can be converted into synthetic fuel which can reduce aviation carbon emissions by up to 80%. SAF can be blended with conventional jet fuel, and since it’s chemically similar to jet fuel, it won’t require any engine modifications to introduce.
However, high production costs present scalability challenges for SAF, and limited availability necessitates further research and investment in production technologies.
Food and Beverage Industry
CO2 is widely used for carbonation in soft drinks, refrigeration, and packaging processes to enhance product preservation.
Chemical Manufacturing and Chemical Feedstock
Industries utilize CO2 as a raw material to synthesize important chemicals such as methanol, urea, and polycarbonates. What’s more, CO2 can be converted into valuable products such as plastics, resulting in less reliance on fossil fuel-derived materials. Taking it a step further, companies like Fortnum Recycling & Waste in Finland[1] have succeeded in making biodegradable plastic from captured CO2.
Mineralisation and Construction Materials
Innovative techniques allow CO2 to be used in producing low-carbon concrete and building materials, effectively sequestering carbon in long-lasting structures. The CO2 reacts with minerals to form stable carbonates, which can be used in construction materials like concrete. In so doing, this method reduces emissions from one of the largest polluting industries—construction.
Bio-based Utilisation (Algae and Plants)
Certain plants, algae, and microbes can absorb CO2 and use it to grow. This process can produce biofuels, biomass, food, or other bio-based materials. These organisms can be cultivated on non-arable land, which then bypasses the food vs fuel conflict.
There are some hurdles to overcome, though, as establishing large-scale facilities requires substantial investment. Also, environmental conditions can affect productivity, leading to inconsistent results.
Pharmaceuticals and Medical Use
CO2 finds various applications in medical fields, including cryotherapy, where it is used for its cooling properties.
Enhanced Oil Recovery (EOR).
While fossil fuels continue to be needed, CO2 can be used for Enhanced Oil Recovery (EOR) and at the same time sequester large amounts of CO2 for centuries. The oil sector users CO2 for EOR, injecting it into wells to increase oil extraction efficiency while simultaneously storing some of the gas underground.
On the positive side, EOR is a proven technology that enhances oil production, and this method reuses CO2, thus reducing emissions associated with oil recovery operations.
But, there is also negative sentiment towards EOR as it remains tied to fossil fuel production, which generates additional CO2 emissions. It can be seen as a license to keep on using fossil fuels and as greenwashing this industry.
CO2 as a new material
Carbon nanotubes and graphene are some of the latest man-made materials which are currently used in specialised applications. The availability of large volumes of CO2 allows for the possibility of using carbon fibres for industrial wiring and the widespread replacement of steel and concrete by carbon composites.
Challenges of CO2 Utilization
While CO2 utilization presents numerous advantages, it faces some barriers to widespread implementation, with high costs being the most pressing.
Transport Costs
Transporting CO2 from remote capture sites to utilization facilities is often expensive. Furthermore, developing the necessary infrastructure like pipelines is both costly and time-consuming. Additionally, there are safety risks associated with transporting large volumes of CO2 under high pressure.
Energy and Operational Costs
Many processes that convert CO2 require substantial energy inputs, which can limit their overall carbon-saving potential. While investing in renewable energy sources could alleviate this issue, it also adds to the initial outlay costs.
Conclusion
A collective call to action is needed for industries and governments alike to invest in carbon dioxide removal, storage and utilization technologies, aiming for a meaningful impact on global emissions. We need active policies for carbon capture and reuse/sequestration which encourage investment by industry and academia to achieve the targets set out to avert wide-spread climate-related disasters.
For more:
What is Carbon Sequestration?
DAC Technologies
How Does Direct Air Capture Work?
Interested in carbon capture technology?
Sources used in this blog include:
www.iea.org
www.energypost.eu/10-carbon-capture-methods-compared-costs-scalability-permanence-cleanness
www.neonscience.org/observatory/observatory-blog/what-role-do-deep-soil-minerals-play-carbon-storage
https://www.weforum.org/agenda/2023/12/airlines-sustainable-aviation-fuel-carbon-targets/