Monday, September 13, 2010

Carbon Capture and Storage (CCS) - Yay or Nay?

A new paper (1) published in the prestigious American Chemical Society journal, Environmental Science and Technology, has put the cat among the pigeons over carbon capture and storage (CCS). It argues that the colossal amount of money that CCS would entail globally would be better spent on "virtual CCS", meaning per se that instead of actual CCS, the emission of carbon be avoided in the first place by a wholesale implementation of non-fossil energy sources, specifically wind and nuclear power. As a statistic to prove the point, it is estimated that one wedge (billion tonnes) of carbon in the form of CO2 sequestered by CCS would cost $5.1 trillion over 50 years, while the same amount of money used to build wind-turbines would save 1.91 "wedges" worth of CO2 over the lifetime of the windmills. A strong rebuttal to this case is presented in the September Chemistry World (2), which calls for a parallel development of CCS and non-fossil energy rather than the exclusion of the former.

Since 100 million tonnes per DAY of CO2 would need to be so sequestered by CCS the engineering required to bring it to fruition is phenomenal. There are essentially two methods to remove carbon from fuel: post-combustion and pre-combustion. Post-combustion, CO2 is removed from flue gas by passing it through a liquid amine which dissolves the CO2. Pre-combustion, the fuel (coal, gas, biomass) is processed into a mixture of CO2 + H2 and the CO2 is removed. Either way, the CO2 must be put somewhere, for which strategies include pumping it into rocky formations (such as depleted oil and gas wells) at a pressure of 100 atmospheres, or even piping it in liquid form under pressure onto the sea-floor where it is cold enough and the pressure high enough that it is hoped the material will stay there, assisted by the formation of CO2-hydrate.

(1) C Tsouris, D S Aaron and K A Williams, 2010, Environ. Sci. Technol., 44, 4042


Yorkshireminer said...

Dear Chris,
I have always thought that carbon capture was a bit of a joke. I do not know but I would suspect that you would have to use a third more energy to extract the Co2 from coal fired stations and where is the energy coming from burning more coal which in turn has to have its Co2 extracted and so on infinitum. that is apart from all the coal that must be burned to supply the steel and infra-structure for the carbon capture in the first place a little bit like chasing your tail. A much more sensible way of going about it would be to plant more tree that could be ramped up over a few year than embark on this stupid way of doing things. that is apart from insulation houses, which means that you don't use the energy in the first place. Although I will admit that it cost a hell of a lot of energy to produce the insulation the results in energy saving must be far better in the long run To me it a bit like improving the MPG of a car by 10% the engine might be more expensive but the energy used to improve the efficiency is more than compensated in the energy saved over the life of the vehicle.

Yorkshireminer said...
This comment has been removed by the author.
Professor Chris Rhodes said...

Hi Dave,

yes, that's my understanding too... that you would need to build a third coal-fired power station for every two other to cope by CCS with the carbon emissions (from all three).

Yes, there are, for all vast schemes of engineering as are necessary for widescale wind, solar, nuclear and so on, the costs of the energy for the steel manufacture etc., much of which would have to come from coal, at least in the immediate decades.

My hunch is that CCS will never happen on the grand scale, and whatever we can develop by way of non-fossil energy will be necessary to help substitute for the impending depletion of fossil-resources in any case.

Nice to hear from you!

By the way, what did you think of my novel, University Shambles? It was intended as a black comedy but sadly is ever closer to the truth especially with the government cuts of 13% to the UK university budget over the next 3 years.



Mark said...


This might be a little off topic but I think you might find this of interest. A popular website here in the states has an article about a man who spent the last 20 months living without money by choice and then writing a book about it. To me his life style is way too Spartan but he could be the prototype of how we live if your prophesies of peak oil come to pass.

You can read the article by using the link below.

Professor Chris Rhodes said...

Hi Mark,

yes, his lifestyle is a little too frugal for me too, but congratulations to him for his achievement. Truthfully, though, it is only possible for a smallish number of people to live this way, and within a rather less Spartan overall society.

There was a woman in the UK who also lived for a year, I think?, on £1 a day and she also wrote a book about it.



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