When Formula 1 announced its courageous ambition to become carbon neutral by 2030 in late 2019, much of the focus was on fuels. Although they represent only around 0.7% of the 250,000 tonnes of CO2 carbon footprint of the championship, the multiplier effect of this technology is enormous.
A much larger proportion of the total footprint resides in transporting people and equipment around the world, and this is also high on the agenda – with F1 engaging with the aviation industry and academia on sustainable aviation fuels (SAF). Many people, however, point out that the cars themselves are built using a large amount of carbon fiber and wonder what impact this has on Formula 1’s carbon neutral ambitions and whether any alternatives are considered.
It is perhaps useful to recall what is meant by « carbon fiber », or more precisely, by carbon fiber composites. These materials are made of carbon fibers that are usually woven into a web and then impregnated with a resin. In the uncured state, the resin binds the fibers together with enough freedom to allow the fabric to be draped in a mold. Structures are normally made up of several layers of fabric and these layers can be separated by a honeycomb stabilizer to create geometric rigidity. Once polymerized at temperature, the resin hardens and the structure becomes a rigid component.
There are many types of carbon fibers and they can be woven in different ways, but all the fibers used in F1 are of a type known as PAN fibers. They are so called because the precursor from which they are made is a polymer called polyacrylonitrile. It is an organic material that is spun into fibers, which are then chemically stabilized.
At this point the fibers are white, but the next process is carbonization, which takes place at very high temperatures and transforms the fibers into tightly bound carbon crystals. The fibers are then graphitized at approximately 3,000 degrees centigrade. They are then grouped and finally spun to obtain the specific type of yarn required.
Carbon exists in many different forms, which chemists call allotropes. They range from very soft graphite to extremely hard diamond, both of which are forms of carbon. The carbon of carbon fiber can be modified to be either very strong or very stiff or, to some extent, both. This is what has made it such an attractive material in applications where extreme properties are required at very light weight.
Carbon fiber was first developed for aerospace by the Royal Aircraft Establishment in Farnborough, England in the 1960s, but it was motorsport that demonstrated how it could be used in a variety of applications. industrialized applications.
Carbon fiber has been used for decades in F1
Of course, in the 1960s and even in the following decades, few people thought about the carbon footprint of the materials they used, but since this subject became topical, research has been undertaken to find substitutes for fibers and resins, which are also hydrocarbon-based.
The basic principle of achieving strength and stiffness by combining fibers and resins is not new. The fiberglass used in the bodywork of certain cars for many years exploits exactly the same principle, as does the construction of houses by a process called « cob ».
This process has been used since the 12th century in Europe and consists of an armature – the wattle – made of wood and a sticky clay-like substance used in exactly the same way as a resin hardened at room temperature in the modern materials. The idea of a biocomposite is therefore not really new, but when attention has turned to the use of biomaterials as structural composites, it has highlighted the amazing properties of carbon fiber composites.
A modern biocomposite is made from natural fibers, often flax, although hemp and jute are also used. Since they are bio-based, they are considered sustainable, although like first-generation biofuels, if they use arable land for their production, they can compete directly with growing food.
In general, the production of natural fibers is less energy intensive than that of synthetic fibers and their ease of biodegradability as well as their high calorific value in the event of incineration give good results at the end of their life. Resins can also be bio-based and a bio-based resin derived from food waste has a high transition temperature which makes it suitable for a number of components.
Biocomposites are unlikely to be used for components requiring high strength or stiffness – such as a monocoque or wishbone – but there are countless applications where the reduced properties do not compromise the design.
So what is the greenhouse gas reduction of a natural composite compared to a carbon composite?
Unfortunately, this question is more difficult to answer than it seems. The mechanical properties of natural fibers are not as good as those of carbon, and although producers have some interesting ways of mitigating this drawback, a structural component made from a flax-based composite will be heavier than a component made of carbon.
Natural fibers are increasingly present in GT
Although it is claimed that the flax-based composite, on an equal weight basis, can achieve a 75% reduction in carbon footprint, this does not take into account the difference in weight of a finished component of strength or comparable rigidity. Similarly, in a full life cycle assessment, this figure does not take into account some of the other processes and components used in production.
While this may sound negative, it is not. Biocomposites are unlikely to be used for components requiring high strength or stiffness – such as a monocoque or wishbone – but there are countless applications where the reduced properties do not compromise the design.
I think we will see a lot more biocomposites in the future and just as the properties of carbon fiber have improved over the years through continuous development, natural products can also be improved. This will be done by improving processes, or even by genetically engineering the plants from which they come.
As F1 aims for carbon neutrality, what does the future hold?