Professor David Keith of the University of Calgary is working on a device that removes carbon dioxide (CO2) directly from ambient air.
Keith has built a tower, 4 feet wide and 20 feet tall, with a fan at the bottom that sucks air in. Keith expects the air coming out at the top to have approximately 50% less CO2 than the air coming in.
The tower features in an episode of Discovery Channel’s new “Project Earth” series on television. The series has the largest budget of any in Discovery Channel’s history, and it may eventually attract a global viewership of more than 100 million.
The episode on Keith’s research has already aired in the U.S. - if you're missed it, you can watch it on Discovery Channel’s website, at: http://dsc.discovery.com/tv/project-earth/project-earth.html - click on “Episodes.”
If the program hasn't aired in your country, you may not get access to the online episode, but you can read more at: http://dsc.discovery.com/tv/project-earth/lab-books/fixing-carbon/guide1.html - also click on the links under "MORE CARBON"
The picture below describes the Big Picture of recycling, in which I envisage aviation to fund CO2 air capture. When talking about recycling, most people think about recycling of industrial products only. They may also see composting of organic waste as a (second) way of recycling. Instead of composting, I actually envisage organic waste to be burned by means of pyrolysis, in order to produce agrichar and hydrogen. I also envisage a third way of recycling that includes removing CO2 from the air. This CO2 could also be used for the production of agrichar and for commercial purposes such as to enrich greenhouses and for the production of building material, carbon fiber, etc. Furthermore, this CO2 could be used as fuel for aviation.
To tackle emissions by aviation, we can switch to airplanes and helicopters that are powered by batteries and hydrogen, or switch to fuels other than fossil fuel. Growth of algae could be assisted by such captured CO2, which could also be turned directly into fuel.
By financially supporting air capture of CO2 and the use of such CO2 to produce fuel, aviation could close the circle of this third way of recycling. This could make aviation environmentally sustainable. Since government is such a large user of aviation (both the military and civil parts of government), it makes sense for the government to start funding such air capture as soon as possible. An international agreement, to be reached in Copenhagen in 2009, could further arrange for the proceeds of environmental fees on commercial flights to fund such air capture and its use for fuel.
Further links:
http://dsc.discovery.com/tv/project-earth/explores/carbon.html - Discovery Channel
http://www.ucalgary.ca/news/september2008/keith-carboncapture - David Keith
http://www.ucalgary.ca/~keith/AirCapture.html - David Keith
http://www.ucalgary.ca/~keith/Misc/AC%20talk%20MIT%20Sept%202008.pdf - M.I.T.
views.blogspot.com - by Sam Carana
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Comments: 23
Since electricity represents much of the cost of taking carbon out of the air, it makes sense to locate such air capture devices close to wind farms, which can produce large quantities of surplus electricity at night and early in the morning when demand for electricity is low. The surplus of electricity produced by wind turbines at night could be used to recharge batteries of electric cars, produce hydrogen and operate air capture devices. Such quadruple use of wind turbines could lower the cost of wind turbines and thus the price of electricity for all. Storing electricity in car batteries and in the form of hydrogen could also help smooth out glitches, peaks and outages in the electric grid.
I just updated the article, to explain how I envisage such CO2 capture from the air to be funded. I'll post more on the cost of this later.
Very interesting article! But is there not a chance that this is akin to draining the Atlantic with a teaspoon? And how much carbon is added to the atmosphere by the construction of such devices? Is there a net gain?
The sheer vastness of the atmosphere and the tiny (relatively) character of this device look like a wish more than a solution, but it would be nice if I'm totally wrong there.
If there is in fact, a net gain, the funding would have to be from general tax revenues and could constitute a good investment. I can't see where you can work a prebate into this technology, but give it a try!
Thanks, Sam!
As an afterthought, I would submit that it would be much easier and more practical to not put the carbon into the atmosphere than to attempt to remove it in this fashion.
Just my thoughts on the subject.
Some cost modeling is done in the above-mentioned M.I.T.-paper. The tower looks like it's made mainly of plastic, which could be made with carbon produced by such a tower. Inside the tower, limestone or a similar agent is used to bind the CO2 and to split CO2 off by heating it up. This constitutes a small one-time cost, as the limestone is recycled within the tower. The main cost appears to be the electricity to run it.
"Keith and his team showed they could capture CO2 directly from the air with less than 100 kilowatt-hours of electricity per tonne of CO2. Their custom-built tower was able to capture the equivalent of about 20 tonnes per year of CO2 on a single square metre of scrubbing material... (Even) if you used electricity from a coal-fired power plant, for every unit of electricity you used to operate the capture machine, you’d be capturing 10 times as much CO2 as the power plant emitted making that much electricity,” Keith says. [source]
In the U.S., each person emits about 20 tonnes of CO2 annually. In other words, each person in the U.S. could remove as much CO2 from the air with such a device, with an annual 2 Megawatt-hours of electricity to operate it. By comparison, a refrigerator consumes about 1.2 Megawatt-hours annually [2001 figures]
James: ".. funding would have to be from general tax revenues and could constitute a good investment ... (but) it would be much easier and more practical to not put the carbon into the atmosphere than to attempt to remove it in this fashion."
It's hard if not impossible for the aviation industry to 'not put carbon into the atmosphere'. More and more countries are now adding environmental fees to flights, so why not use the proceeds of such fees to finance projects that actually remove CO2 from the air?
Yes, that's a good question, Bill. Planting more trees alone seems inadequate if temperatures rise further and the forests burn away or turn into deserts. I think we need a more comprehensive approach and there's a lot of scope to enrich the soil with agrichar. Trees can lock up between of 1 and 20 tonnes of CO2 per hectare. The soil can contain even more CO2. Organic material buried in the soil in the form of peat can lock up some 285 tonnes of CO2 per hectare. With agrichar, some 363 tonnes of CO2 can be locked up in the soil, according to an article in New Scientist. Furthermore, agrichar can remain in the soil for thousands of years and it makes the soil hold more water, microbes and other organic material, thus also increasing soil fertility. CO2 captured from the air can be used to produce agrichar, as indicated on the image underneath the article.
On the other hand Hydrogen, I mean "pure or practically pure" Hydrogen is still very expensive to get.
So there is a solution in which I have been involved since 1998 and which has recently been quoted on the OTC:MNGA. If you want to know more about this you may go to www.magnegas.com or just email me privately to avoid boring the whole community!
This is a type of recyclers, built in Florida, which take as input polluted waters loaded or not with oils, animal or human manure, etc. I mean usually municipal waters, vegetable or mineral oils, etc. and get as out put clean waters and a gas called MagneGas which is in fact made of 2/3 of Hydrogen.
This gas is in some way equivalent to Natural Gas, however it is lighter than air and therefore cannot explode.
Since 1999 cars have been running with such a gas. No engine change but, when the engine is not designed for gas, a device has been added to decompress the gas for a cost of less than $1,500 because specially designed for each car. Usually the device will not exceed $400 in usual production.
The cars run indifferently on gasoline or MagneGas with the same yielding.
This gas has many other uses, indeed.
However one interesting point is that, at the car exhaust, it is ejected in the atmosphere about 9 to 12% of Oxygen. And such property becomes important when one considers the air properties: presently it contains 20.8% of Oxygen while in a stat I found from 1931 it was 21.2%. And this may explain why we all feel much more tired than former generations.
BTW, MagneGas is selling its recyclers outside the USA mainly in emerging countries. Maybe, as press stated a week ago, Dunedin in Florida, will buy a recycler as well.
Cut carbon to 350ppm, says James Hansen. CO2 levels are far higher and rising (see image below). That means we need air capture.
Gilbert: "Of course a solution exists: to use Hydrogen to burn most of the last CO2 particles."
Not only would it be expensive, it would merely produce methane, which is a more powerful greenhouse gas than carbon dioxide, at least in the short term. When burned, it would just release the carbon back into the atmosphere in the form of carbon dioxide.
Gilbert: "...take as input polluted waters loaded or not with oils, animal or human manure, etc. I mean usually municipal waters, vegetable or mineral oils, etc. and get as out put clean waters and a gas..."
Instead of using organic waste to produce syngas, I would prefer to see pyrolysis used to produce hydrogen and agrichar. The hydrogen can then be used to power cars, boats, etc. Electricifcation of vehicles makes more sense than switching to natural gas or syngas.
We need to get rid of coal-fired power plants altogether, Larry. Wind power already is a cheaper alternative, cheaper than coal, as confirmed by GE who makes a lot of wind turbines. So, why spend additional money on efforts to capture CO2 at smokestacks, if such efforts can only be successful to some extent, while there are also other emissions that justified their closure, such as mercury. Mining and transporting coal will still cause emissions. And look at the wastelands left behind after mining.
It makes more sense to build air capture facilities at places with a massive surplus of electricity, such as close to offshore windfarms. The coast in front of New York has some of the best wind in the world and the strongest winds often blow at night when there's little demand for electricity. Surplus power from wind turbines already occurs in Denmark and Spain, and this will only increase with more wind turbines. Such surplus power could be used to capture CO2 from ambient air, to charge batteries of electric vehicles, to produce hydrogen, etc, thus facilitating clean industries and making wind power ever more economic in the process.
This method is now discussed in the article Artificial Trees Could Cool Climate at the Discovery Channel, which explains that dry alkaline resin soaks up acidic CO2 from the air. After one hour, the resin is completely saturated with CO2. Adding water releases the CO2, which is then captured and stored. Drying the resin makes that it can be reused to capture CO2.
To harvest one ton of CO2 per day requires about 32,800 feet of resin. Two to three years from now, harvesting will cost about $150 for each ton, GRT estimates. When the technology is fully mature, the price will be as low as $20. For more background, also see this recent article in the Economist.
Further details www.21stCenturyChallenges.org