Researchers at the University of Calgary say they have a machine that can extract carbon dioxide from the air at a reasonable cost and using relatively little energy. From what I can tell, the CO2 extracted would still need to be buried somewhere. Even so, if such technologies prove cost effective and scalable, they could potentially play a role in stabilizing climate.
More details are in this PDF. Apparently, the tower can capture 15 tonnes per year of CO2 per square metre and each tonne of capture requires 81 kilowatt-hours of electricity (about $4 worth). Estimated total costs per tonne (including capital) range between $12.80 and $43.80.
Could this solve the whole climate problem, if we built billions of them?
Well, human CO2 emissions are about 40 billion tonnes per year. A basic cost estimate would therefore be $512 billion to $1.752 trillion, with higher initial costs for capital deployment. That is high but not impossible. Also, we would presumably cut emissions where doing so would cost less than air capture.
My biggest concern is whether the technology works as advertised and whether it could be scaled up to have a meaningful impact. I don’t see any reason to dismiss its potential outright, though I also don’t see sufficient evidence to say that this is a silver bullet for dealing with climate change.
Oh, and those prices don’t include the cost of burying the CO2, which could be far higher than the capture costs.
As discussed before:
“According to Lynn Orr, director of the Global Climate and Energy Project at Stanford, using a quantity of infrastructure equal to that presently used to extract oil, we could sequester about 14% of humanity’s fossil fuel related emissions. That is about half the combined output from large factories and power stations – the kind of facilities where CCS is most likely to be used. According to an article in Nature, $80 billion dollars of investment per year would be sufficient to capture “several million tonnes of carbon per year.” Burying gigatonnes will presumably cost several orders of magnitude more.”
Published online 29 April 2009 | Nature 458, 1094-1097 (2009) | doi:10.1038/4581094a
News Feature
Climate crunch: Sucking it up
It’s simple to mop carbon dioxide out of the air, but it could cost a lot of money. In the second of three features on the carbon challenge, Nicola Jones talks with the scientists pursuing this strategy.
When Frank Zeman made a device to mop carbon dioxide out of the air of his laboratory at Columbia University in New York, it didn’t look like a machine that could save the planet. Black tape held together plastic parts eaten away by lye; baking soda encrusted the outside. If someone walked behind the air intake (which looked like a grey hair dryer), their exhalations would interfere with the results. But the contraption worked.
Such a device, if scaled up and perfected, could be used to dial back Earth’s greenhouse thermostat by taking CO2 straight out of the sky. Although Zeman’s fully functioning desktop device has not yet made it out of the lab, others have developed parts of bigger and more ambitious devices, some of which are heading for commercialization. All are imperfect, but they all work, and that undeniable fact is turning air capture from a ‘what-if’ pub discussion into a serious proposal.
“The bare-bones chemistry of carbon capture is simple. The simplest thing to do is to expose air to a sorbent of lye (NaOH). This reacts with CO2 to create a solution of sodium carbonate. It’s so simple that Klaus Lackner, also of Columbia University, once helped his daughter to do it for a school science project. To get the carbon out of solution, a trick can be borrowed from the pulp and paper industry: when slaked lime (Ca(OH)2) is added to the mix, particles of calcium carbonate settle out. Throw this into a kiln and you are rewarded with a pure stream of captured CO2 and quicklime (CaO), from which the sorbent can be renewed.”