Harvard applied physics professor David Keith is building a machine that can suck carbon dioxide from the air. Keith has started a company called Carbon Engineering that has attracted venture capitalists that see a future for this technology.
The machine uses a three-step process to filter the air and separate and sequester the carbon dioxide. First, a fan sucks air into the machine where it enters a 31-foot-long chamber filled with wavy plastic material. A sodium hydroxide solution runs down that plastic and reacts with the CO2 to pull it out of the air and turn it into carbonate solids. Those solids then go into a 900 degree Celsius kiln where they're broken down and become a stream of pure CO2. That pure CO2 is then capture where it can go on to be stored underground or used for other purposes.
The machine reuses ash left behind in the kiln to regenerate the sodium hydroxide solution and the process continues.
Of course the removal of the CO2 from the air is never the tricky part of these projects, rather it's what is done with the captured CO2 that leaves people feeling unsure. The permanence of underground storage is still untested.
But the potential for the technology has generated some interest. Bill Gates and other billionaire investors have given money to Keith's project and Keith himself hopes that it can be scaled up to a size that could actually make a positive impact on the environment.