◼ TECHNOLOGY Bloomberg Businessweek December 23, 201924
PLANT: COURTESY CARBON ENGINEERING. ILLUSTRATION BY LIA KANTROWITZ; DATA: CARBON ENGINEERING; IHS MARKIT◼Amountcaptured
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captureplant
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allcarsin theU.S.in 2018, Harvard applied physicist David Keith and
others wrote an article for the journal Joule explain-
ing how it could be done for $94 to $232 a ton using
inexpensive, off-the-shelf components.
Now a company Keith founded—Carbon
Engineering, in Squamish, B.C.—is working to turn
those engineering estimates into reality. It’s prepar-
ing to construct a plant that’s designed to remove
1 million tons of CO 2 from the atmosphere annually.
It will be by far the world’s largest, offsetting the
emissions of 250,000 cars. The company announced
the million-ton plan in September, just months after
saying its goal was a half-million tons a year.
Carbon Engineering’s plant will be built at an
undisclosed location in the Permian Basin of Texas
in cooperation with a unit of Occidental, which will
use the captured gas for oil recovery. (Chevron,
Australian mining giant BHP Billiton, and Microsoft
co-founder Bill Gates are among the company’s
other investors.) Construction is scheduled to begin
in 2021 and finish in 2023. If it works, Keith’s com-
pany intends to roll out hundreds and eventually
thousands of identical plants all over the world.
Chief Executive Officer Steve Oldham says in
a video on Carbon Engineering’s website that the
plant will remove CO 2 at a cost of $100 to $150 a ton.
He’s been more cautious recently, saying in an inter-
view only that the cost will come in under $200.
The other two principal carbon-capture com-
panies are also trying to scale up. Zurich-based
Climeworks has 14 small plants in operation in
Europe. The biggest, in Switzerland, captures
900 tons of CO 2 a year from the atmosphere at a cost
of $600 a ton. It has plans to get down to $200 a tonin three to four years and to $100 by 2030. New York-
based Global Thermostat aims to suck up 2,000 tons
of the gas each year at a plant it’s building in Tulsa.
Peter Eisenberger, former head of physical sciences
at Exxon Mobil Corp.’s research and development
department, is its chief technology officer; Graciela
Chichilnisky, an economist at Columbia, is the CEO.
There’s no question that direct air capture is rel-
atively high-hanging fruit. Even if the cost reduc-
tions are achieved, it will still be more expensive
than cutting back on emissions. And it’s costly vs.
other “negative emissions” alternatives: Planting
trees costs $15 to $50 per ton of carbon dioxide
removed, according to a recent study by the National
Academies of Sciences. Capturing CO 2 from concen-
trated sources, such as flue gases of power plants, is
also cheaper than grabbing it out of plain air, where
it makes up only four molecules out of every 10,000.
So why pursue it? Because emissions reduction
alone won’t be enough to stop the planet from heat-
ing up. Some emissions will continue for decades—
battery-powered passenger jets remain a remote
prospect, for example. As for negative-emissions
technologies, there’s not enough room for all the
forests we’d need to plant to stop global warming.
Ditto for croplands for growing biomass for fuels.
And equipping smokestacks to capture carbon won’t
be enough, as half of all emissions come from less
concentrated sources.
Direct air capture is workable because CO 2 is an
acid, meaning it reacts strongly with various bases to
form salts. Carbon Engineering will use fans to drive
air through plastic sheets dripping with potassium
hydroxide, producing a salt, potassium carbonate.◀ A direct air
capture pilot plant at
Carbon Engineering
headquarters in
Squamish, B.C.● CO2 change over
one year