Ingolstadt, September 10, 2020 – The Swiss company Climeworks is building the world’s largest direct air capture and storage facility for converting atmospheric CO2 to rock in Iceland. Audi is partnering with the Zurich-based environmental start-up and promoting a future technology with the project. The facility will filter 4,000 metric tons of carbon dioxide from the air and mineralize it underground. Climeworks is removing 1,000 metric tons thereof from the atmosphere on behalf of Audi.
The process – how the CO2 gets deep underground
With direct air capture technology, carbon dioxide is extracted from the ambient air and air free of CO2 is returned to the atmosphere. Climeworks’ new facility in Iceland transports the CO2 filtered out of the air below the Earth’s surface, where natural processes then mineralize it. The carbon dioxide is thus permanently removed from the atmosphere.
The facility first draws in air and feeds it into the CO2 collector, which contains a selective filter material. This uses a specially developed adsorbent to bind the CO2 in the air. When this filter is saturated with CO2, it is heated to 100 degrees Celsius using waste heat from a nearby geothermal plant to release the CO2 molecules. Water from the Hellisheiði power plant then flows through the facility and transports the carbon dioxide roughly 2,000 meters below the surface of the Earth. The CO2 molecules react through natural mineralization processes with the basalt rock and are converted to carbonates over a period of several years, thus permanently storing the CO2 underground. The water returns to the cycle of the geothermal power plant. The facility will operate 24 hours a day, seven days a week, and will filter 4,000 metric tons from the atmosphere each year. One quarter of that will be credited to Audi. 80,000 trees would be needed to bind this amount naturally.
The direct air capture technology from Climeworks boasts two major advantages: Lifecycle analyses show that 90 percent of the CO2 filtered out of the air is effectively and permanently stored underground. This high reduction capacity makes the facility particularly efficient. The technology can also be scaled up to the megaton-per-year range and thus harbors great potential from the future.
Iceland is one of several places on Earth offering the ideal conditions for this process. Its volcanic origin makes the country one of the world’s most potent geothermal regions. The particularly high geothermal energy means that the Earth’s heat can be converted to electricity cost-effectively and virtually CO2 neutrally. Furthermore, the rock in Iceland has the ideal composition for storing large amounts of CO2.