© Climeworks / Julia Dunlop

Awesome extrac­tors

Clime­works, a Swiss company, filters carbon dioxide out of the air to contribute to climate protec­tion.


Waste incin­er­a­tion is not exactly some­thing that makes people think of improved air quality. But in the commu­nity of Hinwil in the Swiss canton of Zurich, the two aspects are being combined in a project that’s unique world­wide. On the ground, a local waste manage­ment authority converts trash to slag by burning; above, Clime­works turns carbon dioxide into plant food. It’s an effi­cient cycle as the waste incin­er­a­tion provides energy for the CO2 extrac­tors on the roof. They bring the green­house gas via a pipeline to a green­house 400 meters away, where a nursery uses it to boost the growth of cucum­bers and toma­toes. The process turns 900 tons of CO2 from a climate nemesis into a growth booster.

From dream to climate target

The tech­nology is called direct air capture (DAC) and the plant was devel­oped by Christoph Gebald and Jan Wurzbacher. The two engi­neers became acquainted early in the millen­nium during their studies at the Swiss Federal Insti­tute of Tech­nology in Zurich. “We decided on the first day to found a company together,” says Wurzbacher. “That was our big dream.” In 2007 they began research on tech­nolo­gies for extracting carbon dioxide from the air. Just two years later, they founded Clime­works.

The company has set itself some ambi­tious goals: “Tech­nolo­gies for removing CO2 from the air are indis­pens­able for reaching the two-degree target,” says Valentin Gutknecht, Marketing Manager at Clime­works. The company would like to see one percent of world­wide CO2 emis­sions being filtered out of the air by 2025. Doing that would take 250,000 plants like the one in Hinwil. It consists of 18 extractor units that are controlled and moni­tored together. The advan­tage of its modular design: It needs little space, is easily scal­able, and can there­fore be used anywhere.

Useful CO2

The carbon dioxide filtered out of the air by the direct air capture plant can be used for many things, such as renew­able fuel, fertil­izer and carbon­a­tion in bever­ages.

The basic prin­ciple of the CO2 extractor is actu­ally quite simple. A fan draws in air through a filter that captures the CO₂. When the filter is satu­rated, the carbon dioxide is sepa­rated at 100 degrees Celsius. Of course choosing the right process and compo­nents was some­what more compli­cated. “Energy effi­ciency was a very impor­tant aspect for us; we had an eye on it from the begin­ning,” says Wurzbacher. That was a reason for Clime­works to choose large axial fans from ebm-papst. They have to trans­port very high air flow with low pres­sure losses and also be very quiet. “We bene­fited from being able to set up and measure the entire system at ebm-papst in Mulfingen. That helped us to maxi­mize the effi­ciency.”

“Removing CO2 from the air is indis­pens­able for reaching the two-degree target.” Valentin Gutknecht, Marketing Manager at Clime­works

Clime­works is also working on the effi­cient use of the carbon dioxide. Growing vegeta­bles as in the initial project in Hinwil is only one of several possi­bil­i­ties. The CO2 harvested in the DAC plant can also be used for the produc­tion of carbon­ated bever­ages or climate-neutral fuels and mate­rials. The main thing is that it disap­pears from the atmos­phere.

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