Arrhenius permanently stores CO2 in algae cultures
Horw/Rothenburg - Arrhenius uses microalgae in photobioreactors to capture significantly more CO2 from the air than trees. Now, a reactor in Rothenburg in the Swiss canton of Lucerne has been put back into operation. The biomass it obtains is stored in the soil or made available to the bioeconomy.
The startup company Arrhenius, which is based at Lucerne University of Applied Sciences and Arts (HSLU), has filled its photobioreactor in Rothenburg with a fresh starter culture of chlorella algae. According to a statement from the university, these microalgae are used to remove CO2 from the air.
The innovative method behind this process dates back to Reto Tamburini's master's thesis at HSLU, where he developed the first reactors on a laboratory scale. Arrhenius co-founder and HSLU professor Mirko Kleingries had already been researching CO2 capture technologies for 10 years. As a lecturer at HSLU, the third member of the team, Karina von dem Berge, contributes her expertise in business development.
Arrhenius taps into algae’s ability to absorb carbon dioxide from the air. Because algae grow much faster than trees, they bind significantly more CO2 than trees in a shorter period of time. According to calculations in the HSLU report, one kilogram of carbon bound in algae biomass corresponds to around 3.7 kilograms of CO2 removed.
The process essentially involves three steps, explains Tamburini in a video: «First, the algae are cultivated in photobioreactors, where they absorb CO2. They are then separated from the water, dried, and can be stored underground.» This ensures that the captured CO2 remains permanently stored in the ground.
In addition to negative emissions, algae biomass can also be used in dietary supplements, animal feed, or in the production of bioplastics. According to Tamburini, the focus is currently on scaling up the plants. «Once large plants are operational in locations with plenty of sunshine, we will be able to enter the CO2 certificate market,» he said.
