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On-Plant Carbon Capture Much More Efficient Than Air Scrubbing, Study Says

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To get rid of carbon dioxide from our atmosphere, one sure way to go would be capturing the gas directly from the air. However, this is more of a challenge than would be capturing the carbon at the source of its emission, the power plant furnaces, say Stanford and MIT researchers.

A similar study has already been performed by Princeton researchers this spring, when they were saying that a machine that would be able to scrub carbon dioxide of a 1000-MW plant would have to stretch over 30 kilometers.

Now, Jennifer Wilcox and her colleagues at Stanford and MIT, has published a study in the Proceedings of the National Academy of Sciences, according to which it would be much more economically efficient to capture carbon at power plants, cement plants and refineries.

“The concentration of CO2 in outside air is 300 times less than in the coal-fired flue gases emitted from a power plant. The lower atmospheric concentration makes removal from air much more expensive than removing CO2 directly from the flue gases at the source,” she said.

Comparing the alternatives, Wilcox reached the conclusion that it would cost some $1,000 per ton to sequester carbon after it had been emitted and some $50 to $100 per ton to catch it before exiting the furnace.

“Direct air capture sounds great in theory,” Wilcox said. “In reality, though, a lot of energy is required, and using fossil-based energy sources to capture and regenerate the carbon dioxide could readily result in more carbon dioxide entering the atmosphere than is captured.

Furthermore, if we were to follow the first, expensive option, the energy used would not be allowed to come from other coal-powered plants, but from renewables like solar and wind. On the other hand, it would make more sense replacing coal plants altogether than using clean energy to sequester what’s already in the air.

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3 COMMENTS

  1. Jem your still trying to justify reinventing the wheel, the carbon we are extracting from the planet in the form of fossil fuels is also a renewable resource but on a larger time scale. (it takes more time to make it) The question was time and money the simple solution is to increase plant life on the planets surface. Where do you think all those fossil fuels came from anyway. To say the planet cant manage its own carbon is silly it’s done it before. The evidence is in your gas tank. People would like to think of themselves as being a little more important in the scheme of things than they are. However I do believe we can assist the natural order of things. The carbon was not seperated in the past when it was sequestered before so why must it be so now. (thus the reinventing of the wheel) Just take those leaves you normally send to your landfill each year when you rake your yard and bury them. Carbon sequsetered. The advantage to this plan is the biomas that you have buried will some day be come a deposit of fuel. Hopefully we wont need it by the time it’s ready. The point is there is an eaiser way and a more natural way. Just bury the bio mas and let the trees and plants take it out of the air they are far better at it than anything we can come up with.

  2. Joe,
    There isn’t room on the planet to grow enough trees to capture all the carbon from burning fossil fuel and when eventually the wood rotted or burned all that carbon dioxide would be back again. Whether it’s ten years or a hundred years it’s still a problem. The carbon dioxide needs to be buried for geological time scales.

    Below I have reproduced my comment on this paper on another website.

    The article about atmospheric carbon capture costs based on work at MIT misses the point. Nobody has ever suggested that capturing carbon from the atmosphere would be cheaper than from power station flue gas or that current EU carbon dioxide permit costs could cover either.

    But capturing CO2 from the atmosphere allows us to continue using motor vehicles, aircraft etc. without trashing the planet or displacing food crops and wildlife to grow renewable fuel. To stop atmospheric CO2 concentration rising we need to reduce emissions to less than 10% of today’s value.

    The energy requirement for atmospheric CO2 capture depends on the route chosen, but for example Kheshgi showed in his 1995 paper that a route using fairly conventional cement technology to make calcium oxide from limestone required only 164 kJ/mol of net CO2 captured when the calcium oxide was recombined with CO2 to form dissolved bicarbonate in the ocean.

    Even if one accepted the cost of £640/te of CO2 quoted in the article, it is still equivalent to only £1.60 per litre of petrol which is far from being unaffordable by most motorists. And indeed unless the range, cost and recharging time of battery powered vehicles improves dramatically it may well be the preferred option.

  3. Cough! COUGH! Reinventing the wheel is not the solution to a bumpy road. There is a system already in use that sequesters carbon! Thousands of tons per year are removed from the air! It’s called plant life! So if you really want to clean up the co2 just plant a tree, and then take it to the next level and buy or build something that’s made out of wood. You know that coffee table thats been handed down in your family for generations represents sequsetered carbon? Sure it’s convienent to do a study that shows how much carbon is being produced, it makes for talking points but how about somebody do a study and show how much carbon is sequestered on a yearly basis. I live in a log home the carbon in those logs is locked up until the house burns or rots to the ground (not likely to happen, I hope) The point is your not dealing fairly with the carbon, to only look at half the equation is just wrong….unless you have an agenda. Don’t get me wrong I’m for clean energy but spewing crap science to justify an agenda is self defeating and reduces the chances of real progress in the right direction. Apples to apples people. We need the real picture in order to make an informed decision. Stop treating us like we can’t use the internet to find out it’s all one sided.

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