Pulling CO2 from air vital, but lower-cost technology a stumbling block so far: researchers

July 24, 2012
Allen Wright, senior staff associate at the Lenfest Center for Sustainable Development, shows off a material that captures carbon dioxide from the air, which could be used to reduce atmospheric greenhouse gas concentrations. Credit: Lenfest Center for Sustainable Energy

Emerging techniques to pull carbon dioxide from the air and store it away to stabilize the climate may become increasingly important as the planet tips into a state of potentially dangerous warming, researchers from Columbia University's Earth Institute argue in a paper out this week.

The of directly taking carbon out of the air will likely be expensive, but such technology may well become cheaper as it develops and becomes more widely used, and cost should not be a deterrent to developing such a potentially , the authors said.

The techniques would address sources of CO2 that other types of carbon capture and storage cannot, and have the potential to even lower the amount of CO2 in the atmosphere -- significant because the world may already have crossed beyond the point where the climate can be stabilized by just limiting .

"The field of , the field of capture and storage as a community is too timid when it comes to new ideas," said lead author Klaus Lackner, director of the Lenfest Center for . "You cannot rule out new technology simply because the current implementation is too expensive."

Lackner and his colleagues at the Lenfest Center, part of the Earth Institute, summarize the technical and financial obstacles facing direct air capture of carbon in the review paper, "Urgency of development of CO2 capture from ambient air," published July 23 in the journal . Lackner has been working on the problem for more than a decade, and he founded a company in 2004 to work toward commercializing the techniques.

Various methods are being developed to extract CO2 directly from stationary sources such as coal-fired power facilities and steel and cement , storing the CO2 underground or using it for other purposes, such as feeding farms to produce . But these systems do not address the problem of emissions from mobile sources such as cars, trucks and airplanes.

CO2 in the atmosphere, building up from humans' burning of fossil fuels and other activities, has led to warmer average temperatures across the globe, melting ice sheets and glaciers, raising sea levels and producing more frequent extreme weather events. Nine of the 10 warmest years in the modern meteorological record, since 1880, have occurred since 2000; the first six months of 2012 were the 11th warmest on record, based on land and ocean surface temperature measurements, according to the National Oceanic and Atmospheric Administration and the National Climatic Data Center.

CO2 can linger in the atmosphere for hundreds of years; to stabilize and possibly reduce it will take concerted, long-term efforts across the globe – including the replacement of fossil fuels as an energy source. But, the authors contend, that is not likely to happen fast enough.

"Stabilizing atmospheric CO2 will require drastic emissions reductions," the authors write. "Carbon-free renewable and nuclear energy resources are theoretically sufficient for humankind's energy needs, especially if combined with significant increases in energy efficiency. It is unclear, however, whether these resources can be deployed rapidly and widely enough and overcome socio-political obstacles related to cost, environmental impacts, and public acceptance."

That's where carbon capture and storage comes in. These emerging technologies have the potential to nearly eliminate CO2 emissions from fossil fuel plants. But, the authors say, even modest residual emissions of 10 percent from those plants would prevent us from stabilizing atmospheric CO2 in this century. Air capture technology could be used to mitigate that, and also to deal with the potential problem of CO2 leaking from storage systems, some of which include pumping CO2 deep into the ground.

And, the authors said, those systems do not address all the CO2 coming from more diffused sources, such as in the transportation sector. Those sources account for between a third and a half of society's total CO2 emissions.

Developing systems to capture CO2 directly from the air could help. The paper looks at various methods. As CO2 passes through the systems, it is pulled into absorbent liquids or surfaces, then separated out. But CO2 is less concentrated in ambient air than it is coming out of a stationary source like a power plant. The key is to find a way to grab a lot of CO2 out of the air with a minimum expense of energy. Estimating the cost of that technology right now is impossible, the authors said.

But if a mass-produced device could capture a ton of CO2 per day, a million of them, like forests of artificial trees, could capture more than a tenth of humans' total output of CO2 today.

The authors caution that the development of various types of carbon capture and storage should not be seen as an argument for doing nothing about how we burn energy.

"In a way, it's too late to argue that we shouldn't consider [such] solutions. The concern that this kind of technology would give us an excuse not to do anything [to reduce carbon emissions] is wrong, because we're too late for that," Lackner said. "We have to push very hard right now, and we have to have every means at our disposal to solve this problem."

The paper stands in contrast to a report put out last year by the American Physical Society, which flatly states that direct air capture of CO2 "is not currently an economically viable approach to mitigating climate change."

Without dramatic cost reductions, that report contends, other options for reducing CO2 output from decentralized sources will be more economically feasible – including increasing efficiency; switching to cars and other devices powered by electricity coming from non-carbon-based sources, such as nuclear, solar and wind; and using low-carbon fuels created from biological or other materials.

Government-sponsored efforts to foster research and development of carbon capture and sequestration are mostly focused on removing CO2 from stationary sources, and even that technology still faces serious financial and technological challenges.

But Lackner and colleagues argue that many other technologies have started out at extremely high cost, which has dropped as the technology is refined and products are produced on mass scales. They also contend the air capture systems could reduce the cost of transporting captured carbon from stationary sources to storage sites.

"Demanding an assurance of economic viability at the outset stifles innovation, favors incrementalism and keeps game-changing ideas from consideration," the authors said. Even if the technology started with a baseline cost of $600 per ton of CO2, the cost could probably be substantially reduced as the technology develops. "The challenge seems large but no larger than the corresponding challenges in other climate mitigation technologies," they say.

Taking CO2 directly out of the air has been going on for decades on a small scale in submarines and spaceships. Processes for liquefying air already require removal of water and CO2, too.

Lackner, a director and adviser to Kilimanjaro Energy, the company he founded, is studying how certain resins could absorb CO2. He and co-author Allen Wright of the Lenfest Center are shareholders and consultants to Kilimanjaro, one of three companies working on various air capture techniques. (You can view a video of Wright explaining the technology at MIT's Technology Review.)

Another company working on air capture technology, Global Thermostat, was formed by two Columbia University professors: Peter Eisenberger, a physicist who founded the Earth Institute and formerly ran research labs for Bell Labs and Exxon, and Graciela Chichilnisky, an economist, mathematician and entrepreneur.

Lackner and Wright's co-authors include Sarah Brennan, Jürg Matter, A.-H. Alissa Park and Bob van der Zwaan, all affiliated with the Lenfest Center. Matter also works at the Earth Institute's Lamont-Doherty Earth Observatory; van der Zwaan also works for the Energy Research Centre of the Netherlands.

Explore further: Chemically scrubbing CO2 from the air too expensive

More information: "Urgency of development of CO2 capture from ambient air," Proceedings of the National Academy of Sciences

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4.7 / 5 (3) Jul 24, 2012
It's weird, because I read recently that there would be enough storage leakage to render the entire concept pointless...
3.1 / 5 (7) Jul 24, 2012
It still has to be done without increasing net CO2 in the energy life-cycle.

Perhaps wind/solar can provide the enormous energy to make CaO from CaCO3, capture the CO2 product, then use the CaO to capture free CO2 from the atmosphere, then indirectly CO2 from the oceans as they later outgas and reduce acidity. However this takes centuries.
Is someone somewhere making an 'ark' for shellfish to reintroduce when ocean acidity recovers?

What a waste though, having to even consider this now.
If the oil wasn't squandered it could have been used to just fuel the development of alternative energies and remain in reserve for countless more generations. We could have an enviable renewable energy industry and no global warming problem.
2.3 / 5 (6) Jul 24, 2012
"plant more trees" - Freeman Dyson (is smarter than you).
3 / 5 (4) Jul 24, 2012
We could have an enviable renewable energy industry and no global warming problem.

That is a damn good goal worth pursuing. I second that idea!
1.8 / 5 (6) Jul 25, 2012
how much energy will is cost to pull c02 out of the air? how will we make that energy? by releasing more c02????

pulling c02 otu of the air is a scam. even if global warming is not.

you want to lower c02 in the atmosphere, your first goal is finding a way to produce enormous quantities of energy without producing c02, or at least, producing less c02 than is produced with coal and wood --the most c02 intensive of all fossil fuels.

that's the starting point. anything else is a scam because you will only be encouraging more burning of fossil fuels to suppply energy to an endless set of 'solutions' . even energy efficient technology is only useful to reduce c02 if it does NOT encourage more consumption, thereby resuliting in the same amount of c02 being released.

it's this simple, if you want to reduce c02 you basically ahve to start at the beginning, when you decide to release it into the atmosphere.

not rated yet Jul 25, 2012
Also, you need to capture the CO2 that is mixed with natural gas.
Natural gas (methane) is much better than coal, but the CO2 in the mixture should be captured at the gas field and pumped into an empty gas field.
4.3 / 5 (3) Jul 25, 2012
As stated in the article, we might be already past the point where simply reducing CO2 emissions would prevent climate change. These solutions, along with things like blocking/reflecting part of the sunlight hitting earth need to be at least considered.

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