Mar 11, 2009
Converting Carbon Dioxide
“Nothing beats finding vast lakes of oil for the pumping, or vast deposits of coal for the digging; thanks mother nature!” proclaimed Craig Grimes of Penn State University in an emailed response to my skeptical question regarding his work on catalysts that can convert the greenhouse gas carbon dioxide into a fuel, methane.
I report on his fascinating work in the March issue of Intute Spotlight. The process involves using solar power to chemically reduce carbon dioxide back to a combustible hydrocarbon. Grimes suggests that a flow system employed on fossil fuel burning power station chimney stacks could scrub out the carbon dioxide before it enters the atmosphere and provide us with a viable additional energy source.
Playing devil’s advocate, my skepticism was regarding the energy required to produce the catalysts, which are composed of relatively rare minerals, to build and maintain the plant and to decommission it at end-of-life. There are also the costs of actually trapping the carbon dioxide and then transporting the methane produced to sites where it is needed. Moreover, burning that methane then releases the carbon dioxide elsewhere, so it’s not a quick fix.
Grimes retorts that, “The idea is we better
start
figuring out
how to not
put carbon
dioxide into the atmospherewe better start figuring out how to not put carbon dioxide into the atmosphere, and begin to anticipate that our vast lakes of oil and vast deposits of coal are finite. Solar energy is not finite, at least in any conventional sense, but it is diffuse. There are lots of pitfalls with renewable energy sources, which is why coal and oil are cheaper to buy and use,” he told me. “Yes, you have to make the materials, install them, etc. All of that takes time, energy and money. However, outside of praying for a miracle, i.e. Having a faith-based energy policy, we would be well put to start trying to come up with an alternative to coal and oil.”
I also asked Grimes whether the same system might be used to process carbon dioxide sequestered from the atmosphere directly. “Yes, carbon dioxide that is to be ‘buried’ could instead be used as feedstock for the process, so its win win,” he told me. “The idea is not to burn the methane venting it back in to the atmosphere. You burn, collect, recycle, burn, collect, recycle…”
My Intute Spotlight column has an entirely environmental theme this month. Alongside my report on Grimes’ carbon conversion catalysts, we have a write-up on the recent modelling of Antarctic cooling 35 million years ago and a report on new materials that can efficiently extract hydrogen gas from mixtures and so might fuel a future hydrogen economy.
Oomman K. Varghese, Maggie Paulose, Thomas J. LaTempa, Craig A. Grimes (2009). High-Rate Solar Photocatalytic Conversion of CO2 and Water Vapor to Hydrocarbon Fuels Nano Letters, 9 (2), 731-737 DOI: 10.1021/nl803258p
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March 24th, 2009 at 12:08 pm
Thanks for your feedback Louise, I don’t doubt a lot of hard work is being done by lots of workers the world over into such efforts, whether or not it will lead to viable energetic solutions is a different matter, of course. Fingers crossed.
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March 24th, 2009 at 11:31 am
Hard work is currently being carried by out by scientists to develop inexpensive materials that have the capability to turn carbon dioxide and methane from the earths atmosphere into useful industrial fuels by using solar enwergy – I know because I am one of them!
March 22nd, 2009 at 4:00 am
photovoltaic is required to produce electricity only, listen to me, we pay bills for electricity and bills for gas for cooking and to heat water. Photovoltaic has been mastered over dozens of years and it still has low convenience based on production/costs, and materials used to build photovoltaic panels are very POLLUTING. P. panels aren’t everlasting, once you dropped them after many years of use, you pollute the environment with toxic materials- Yet this technology on sunlight conversion can become quite old compared to the new scientific papers reporting in some cases convertions of almost 80-90% of sunlight.
March 22nd, 2009 at 3:46 am
We can’t rely on renewable energies, methane is another energetic resource, we aren’t talking about electricity production. All europe fails and rely on gas importation from Russian stocks. There are many projects eager to store carbon dioxide to be buried underground as a feedstock, instead you could use it for this project, wich right now is as mere as a prototype so leave apart your skepticism: the first cell phones, cars invented likewise the first co2+h20 reverse chemical process to make gas will be subject to million changes if the whole world was publicly adverted, many scientists could develope better patents with machines yelding better results and built on strategic spots, thus leaving no more methane to be extracted from underground, that once burned it produces co2+h20, thus increasing C02 in our athmosphere continuosly. this process will stop further increase of c02, ceasing methane extractions and will help economic crisis with self-sufficient energy production .
March 13th, 2009 at 7:51 am
@Ben, @Bert, @David Thanks for your comments on this. I too am rather skeptical of this kind of research, always have been. There seems to be little point in developing ways to recycle fossil fuels if only to burn them. Any such system cannot be 100% efficient, so I assume with such an approach carbon will continue to flood into the atmosphere. There is also the cost in terms of energy and resources of building the infrastructure to handle such a system in the first place. A cost that might best be applied to finding ways to generate power at the ultra-local level using renewables.
March 13th, 2009 at 7:06 am
I agree with David Henry — I fail to see how this is anything more than an impressive chemical feat if the energy efficiency of the methane capture is less than our current photovoltaic systems — as all it would do is simply displace more efficient capacity for the sake of not actually reducing our carbon dioxide levels (as the purpose of the methane, presumably, is to combust it for energy).
I think much better to pursue non-carbon-emitting sources of energy (nuclear, solar, wind, etc) or some of the more radical cutting edge carbon sequestration techniques based on photosynthesis (like this one based on splitting water: http://blog.benchside.com/2009/03/imitation-is-the-sincerest-form-of-flattery/)
March 12th, 2009 at 10:37 pm
My first thought on reading the above report was that Grimes was delivering an early April Fools Day joke. Then I read the abstract of his paper and was embarrassed by my lack of respect; it reports a significant chemical result. Then I thought about it a bit more, and re-read your and the other comments, and am halfway back to where I started with regard to his proposition. He is essentially proposing a closed energy cycle, with methane being a carrier for solar energy captured by his catalysts. We release the energy by combustion and convert it to electricity, with the carbon dioxide byproduct recycling back to methane. If, and this is a big “if”, the sunlight conversion efficiency of his catalyst is a lot higher than that that of competing solar photovoltaic systems, then he might have something, at least theoretically. Otherwise, why not use the captured sunlight for direct conversion to electricity and avoid the massive new technology commitment? In the long run shouldn’t we get carbon out of our energy equation completely?
I didn’t have ready access to the full paper and don’t know if Grimes provided any conversion efficiency results; the abstract statement of improved efficiency over previous results, while impressive, does not address the photovoltaic comparison issue.
March 12th, 2009 at 6:45 pm
Well has he discovered somehting as, or more efficient than photosynthesis? Is this just an idea, or has he actually discovered a catalyst that can use solar energy to produce a hydrocarbon? Show me the prototype.
March 12th, 2009 at 2:46 pm
I’ve mentioned that idea previously along with the idea of “mining” landfills on at least a few separate occasions over the last 20 years. Once the economic and resources pressure is high enough, it will no longer be a matter of choice. We will be forced to tap the resources in our waste.
March 12th, 2009 at 2:43 pm
I’ve been toying with an “energy reservoir” concept. There are 450 landfill methane capture operations in the U.S. at present. None of these landfills was initially designed to maximize production of methane. Why not deliberately configure landfills to produce methane. By presorting garbage into biodegradable and inert categories and concentrating the methane generating material, a rich energy reservoir can be created.