CO₂-based plastics

Definition

Plastics are polymers and consist on average of 80 percent carbon. Today, this comes almost exclusively from fossil sources such as crude oil. In the future, carbon could be extracted from carbon dioxide (CO₂), which, like biomass (see bioplastic from waste), is a renewable source of raw materials. This would make plastics CO₂-based. Carbon dioxide can be captured from industrial exhaust gases or from the air using the technology “carbon capture and utilisation” (CCU, see negative emissions technologies) and converted into plastics. This transforms the CO₂ from an unwanted waste product into a useful recyclable material. So far, only a few CCU technologies exist that can convert CO₂ directly into polymers. The majority of these are combined biological and chemical processes that result in polymers via several intermediate products such as ethanol, ethylene and methanol.  

In addition to substituting fossil raw materials, CO₂-based plastics have the potential to store CO₂ temporarily or permanently in durable products – provided that suitable storage sites can be found. 

Current applications and opportunities 

The first generation of marketable products is already here. The largest group of CO₂-based plastics is polycarbonates, which are used for transparent, high-strength components, and polyols, which are basic chemicals. Pilot projects are also underway to produce polyurethanes for use in foams such as mattresses, in paints and adhesives, and for elastic components. The Swiss company On is a pioneer in the use of CO₂-based ethylene vinyl acetate in the production of its shoes.  

The opportunities for CO₂-based plastics lie in the defossilisation of the plastics industry. Although only a few applications have so far made it to the market, the range of possible applications is enormous. In principle, all plastics can be made CO₂-based. However, from a technological standpoint, most of the processes required for this are not yet fully developed. Fine-tuning and implementing this technology promotes the use of local resources and reduces dependence on fossil and other imported raw materials. 

For Switzerland, which has scarce raw material resources, diversifying carbon sources towards CO₂, biomass and plastic recyclates (see plastics recycling) is essential to achieving security of supply. The country has a strong research landscape. There is also an established plastics industry for niche applications, while Swiss company Climeworks is also the world’s first company to capture CO₂ from the air. With this combined expertise, Switzerland has what it takes to become a true innovation hub. However, the commercial production of plastics from CO₂ is likely to be limited to high-quality niche applications in the high-price segment for the time being. 

Challenges 

The production of plastics from CO₂ on a large scale is very energy-intensive. In order to reduce the carbon footprint compared to plastics from fossil sources, the energy required for this must be renewable and cheap to produce. The competitiveness of CO₂-based plastics depends heavily on the process costs for CO₂ capture and the efficiency of the conversion processes – both require continuous optimisation, which in turn depends on advances in biochemical processes and in the catalysts used. The high energy demand for the production of CO₂-based plastics puts this sector in competition with others. The economic viability must be examined with a critical eye. 

Whether Switzerland can establish itself as a production location depends on CO₂ pricing: The current CO₂ tax of just under 120 Swiss francs per tonne does not compensate for the high production costs in Switzerland. In addition, there is a lack of incentives to reduce CO₂ emissions in industry, such as the European Union’s emissions trading scheme. Clear rules for factoring in CO₂ savings in these plastics could also be a viable incentive that would promote innovation. 

Focus on industry

CO₂-based plastics make use of local resources, reduce dependence on raw material imports and help build a more secure future by eliminating fossil supply chains. In this way, they offer the industries that use and manufacture them the opportunity to reduce their carbon footprint. In the medium to long term, companies should see their profits increase through the use of this technology. 

Numerous sectors of the economy are involved along the value chain, from CO₂ capture and the conversion of CO₂ into plastics to the application of the products. The crucial factor is the ability of companies to work together and to integrate into the value chain. Successful technology development requires interdisciplinary expertise, particularly in the fields of plant engineering, biotechnology, chemistry, electronics, material sciences, physics and process engineering. Users will benefit from knowledge of life cycle assessment and process and system modelling combined with artificial intelligence. This is because large amounts of data on variable material and energy flows have to be handled, as well as economic aspects. Training in Switzerland offers a good foundation, but it is not enough to meet the demand for workers and specialist knowledge. 

International perspective

By international standards, Switzerland is well positioned in research into CO₂-based plastics. One contributor to this is the National Centre of Competence in Research “Sustainable chemical processes through catalyst design” (NCCR Catalysis), which is being funded by the Swiss National Science Foundation from 2020 to 2027. Investments in pilot and demonstration plants are now required to get the technology working more effectively in practice. 

Future applications 

In principle, all plastics or their basic chemicals can be produced from CO₂. The technology thus has the potential to contribute to a CO₂-negative plastics industry. The scope of application depends to a large extent on the technologies used for the CO₂ conversion. The most technologically advanced are drop-in chemicals for polymer synthesis, i.e. basic chemicals made from renewable raw materials that are structurally identical to their fossil counterparts. New types of polymers are also conceivable for use in agriculture, the food industry and medicine. 

The conversion of CO₂ into recyclable plastics contributes to a circular carbon economy. Possible applications include components for the automotive and electronics industries as well as additives for bitumen and packaging. If waste from CO₂-based plastic products – similar to radioactive waste – can be safely and permanently stored in repositories, i.e. for at least 1000 years, carbon sinks can be created. However, this would require revisions to current waste legislation. It would also be necessary to find suitable storage sites and methods, and to examine an alternative system of levies, such as an advance disposal fee. 

In addition to plastics from biomass and from recycled materials, CO₂ plastics are a promising avenue for defossilising the plastics industry. They could not only help to reduce CO₂ emissions, but also create economic opportunities for Switzerland. In order to fully exploit their potential, technical and regulatory hurdles must be overcome: Although Switzerland has the knowledge and resources to play a pioneering role in this area, favourable conditions and targeted investment in research and pilot plants are essential.