The world's first commercial plant for capturing carbon dioxide directly from the air opened yesterday, refueling a debate about whether the technology can truly play a significant role in removing greenhouse gases already in the atmosphere.
The Climeworks AG facility near Zurich becomes the first ever to capture CO2 at industrial scale from air and sell it directly to a buyer.
"Highly scalable negative emission technologies are crucial if we are to stay below the 2-degree target [for global temperature rise] of the international community," said Christoph Gebald, co-founder and managing director of Climeworks.
The plant sits on top of a waste heat recovery facility that powers the process. Fans push air through a filter system that collects CO2. When the filter is saturated, CO2 is separated at temperatures above 100 degrees Celsius.
There are many critics of air capture technology who say it would be much cheaper to perfect carbon capture directly at fossil fuel plants and keep CO2 out of the air in the first place.
Among the skeptics are Massachusetts Institute of Technology senior research engineer Howard Herzog, who called it a "sideshow" during a Washington event earlier this year.
He estimated that total system costs for air capture could be as much as $1,000 per ton of CO2, or about 10 times the cost of carbon removal at a fossil fuel plant.
"At that price, it is ridiculous to think about right now. We have so many other ways to do it that are so much cheaper," Herzog said.
He did not comment specifically on Climeworks but noted that the cost for air capture is high partly because CO2 is diffuse in the air, while it is more concentrated in the stream from a fossil fuel plant.
Climeworks did not immediately release detailed information on its costs but said in a statement that the Swiss Federal Office of Energy would assist in financing. The European Union also provided funding.
In 2015, the National Academies of Sciences, Engineering and Medicine released a report saying climate intervention technologies like air capture were not a substitute for reducing emissions.
Last year, two European scientists wrote in the journal Science that air capture and other "negative emissions" technologies are an "unjust gamble," distracting the world from viable climate solutions (Greenwire, Oct. 14, 2016).
Engineers have been toying with the technology for years, and many say it is a needed option to keep temperatures to controllable levels.
It's just a matter of lowering costs, supporters say. More than a decade ago, entrepreneur Richard Branson launched the Virgin Earth Challenge and offered $25 million to the builder of a viable air capture design.