Last year, the Paris Agreement saw almost 200 countries pledge to cut greenhouse emissions, in order to keep global temperatures from rising more than 2° C (3.6° F) above pre-industrial levels, before the end of the century. But just curbing the rise in emissions won't be enough – technologies that actively pull more CO2 out of the atmosphere will also be vital. To that end, a new CO2-filtering plant has just opened up near Zurich.
Climeworks, the company behind the technology, calls it a Direct Air Capture (DAC) plant. From its perch on the roof of a waste recovery facility, the DAC plant collects CO2 that the facility pumps into the air, and chemically deposits it onto the surface of a filter. When each filter is completely full, it's heated to about 100° C (212° F) to isolate the CO2, which can then be purified and sold.
In the case of the plant in Hinwil, the pure CO2 is piped to a greenhouse 400 m (1,312 ft) away, where it's used to grow vegetables. But Climeworks says the gas could also be used for a variety of industrial applications, like creating other climate-neutral fuels, carbonating beverages, or simply being stashed away underground.
To make it as efficient as possible, the DAC plant is powered by the excess heat from the facility underneath it. In its current form, the system can capture as much as 900 tonnes of CO2 every year, and to demonstrate its effectiveness the Hinwil plant will operate as a pilot project for three years. After that, Climeworks has outlined some pretty ambitious plans.
"Highly scalable negative emission technologies are crucial if we are to stay below the two degree target of the international community," says Christoph Gebald, co-founder and managing director of Climeworks. "The DAC technology provides distinct advantages to achieve this aim and is perfectly suitable to be combined with underground storage. We're working hard to reach the goal of filtering one percent of global CO2 emissions by 2025. To achieve this, we estimate around 250,000 DAC plants like the one in Hinwil are necessary."
The Climeworks team describes the DAC system in the video below.