The CO₂ capture technology of Climeworks is based on a cyclic adsorption-desorption process that occurs on a novel filter material (“sorbent”). During adsorption, atmospheric CO₂ is chemically bound to the sorbent’s surface. Once the sorbent is saturated with CO₂, the CO₂ is driven off the sorbent through heating the sorbent to around 60-100°C, thereby delivering high-purity gaseous CO₂. The CO₂-free sorbent can be re-used for many adsorption-desorption cycles. The beauty of the process is the fact that over 90% of the system’s energy demand can be supplied by low-grade heat; the remaining energy is required in the form of electricity for pumping and control purposes.

The patent-pending technology has been developed in collaboration with the Professorship of Renewable Energy Carriers at ETH Zurich. The optimization of the sorbent and scale-up of the sorbent synthesis process is carried out in collaboration with the Swiss Laboratories for Materials Science and Technology.