André Bardow, Prof. of Energy and Process Systems Engineering, ETHZ

An industry within planetary boundaries is not only better for the environment, but also for the industry itself. The transformation towards this goal requires all options. The circular economy is the ideal solution. At the same time, we need to rethink the use of chemicals.

Our planet owes a great deal of prosperity to chemistry, pharmaceuticals and life sciences. However, this success also has dark sides: from microplastics in the sea to CO2 in the atmosphere. We must therefore preserve the positive aspects and overcome negative consequences. The CO2 issue requires a move away from fossil raw materials, a double challenge for our industries, since fossil resources provide us with both energy and carbon. The search for the carbon source of the future is still largely open.

Three ways to carbon: biomass, CO2, recycling
Renewable carbon can be accessed in three ways: via biomass, CO2 or recycling of waste. All three routes are currently being intensively investigated, but some principles can already be derived: CO2-neutral industries in the chemical, pharmaceutical and life sciences sectors will use all sources. The specific choice will depend on both regional potential and the molecular character of the products, for which biomass is sometimes and CO2 is sometimes the better starting point.

Where these routes are excessively difficult, we will even have to resort to fossil resources with rigorous CO2 capture and storage. However, even biomass and CO2 are not without drawbacks: land use and energy requirements limit their potential. A CO2-based chemical industry would require 75% of the world's electricity – from renewable sources (1).

Your product is your best raw material
The ideal way to achieve a more sustainable industry is therefore through a circular economy: this actually reduces the demand for primary energy compared to the linear fossil value chain (2). The key is to preserve the molecular structures and the energy stored in them through mechanical and chemical recycling. In the future, the motto should therefore be: your product of today is your best raw material of tomorrow.

Efficiency and resilience through a circular economy
The circular economy not only protects the climate, but also the other planetary boundaries, from ozone to biodiversity. For Switzerland, the circular economy also offers the opportunity to use local resources, reduce dependencies and strengthen resilience. Our companies also have a command of the necessary complex value chains.

How much chemistry do we need?
However, we also have to question the demand for products. Even with optimal processes and recycling rates of over 75%, the plastics industry would not be able to cope with the predicted growth by 2050 within the planetary boundaries (3). The slogan ‘Reuse, reduce, recycle’ thus remains more relevant than ever and will lead us to a better, more sustainable industry.

(1) A. Kätelhön, R. Meys, S. Deutz, S. Suh, A. Bardow. “Climate change mitigation potential of carbon capture and utilization in the chemical industry”. PNAS, Vol. 116 (23), 11187-11194, 2019.https://doi.org/10.1073/pnas.1821029116

(2) R. Meys, A. Kätelhön, M. Bachmann, B. Winter, C. Zibunas, S. Suh, A. Bardow. Achieving net-zero greenhouse gas emission plastics by a circular carbon economy.Science374,71-76(2021).
DOI:10.1126/science.abg9853

(3) M. Bachmann., C. Zibunas, J. Hartmann, V. Tulus, S. Suh, G. Guillen-Gosalbez, A. Bardow. Towards circular plastics within planetary boundaries. Nat Sustain 6, 599–610 (2023). https://doi.org/10.1038/s41893-022-01054-9