2011-05-10 04:24:11Direct Air Capture of dilute CO2 makes 'little sense'
perseus

owlsmoor@googlemail...
78.143.221.111

Direct Air Capture of CO2 With Chemicals

ScienceDaily (May 9, 2011) — The American Physical Society has released a new assessment -- Direct Air Capture of CO2 with Chemicals -- to better inform the scientific community on the technical aspects of removing carbon dioxide from the atmosphere...... It concludes that DAC would play a very limited role in a coherent CO2 mitigation strategy for many decades. Deployment of DAC would not be pursued aggressively until the world has largely eliminated centralized sources of CO2 emissions, especially at coal and natural gas power plants, either by substitution of non-fossil alternatives or by capture of nearly all of their CO2 emissions. For example, it makes little sense to ignore the emissions of CO2 in the flue gas from a coal power plant while removing CO2 from ambient air where it is 300 times more dilute.....

That last point is precisely why I've always been rather baffled by this concept. 
I suppose the advantage of air capture is that CO2 could be captured anywhere rather than having to transport it to the sequestering point.  However, it appears that my suspicions are confirmed here, it's cheaper to do it where CO2 is most concentrated, then pipe it!
2011-05-10 04:45:18
nealjking

nealjking@gmail...
91.33.124.78

I think the point is that the final issue with CO2 is total concentration, not just emissions.

By the time we get total emissions to zero, we will still be over the 350 ppm target that Hansen has been talking about. To reduce concentration below that, we have to go negative: get the stuff out of the air.

2011-05-10 22:36:59
perseus

owlsmoor@googlemail...
78.143.221.111

It should be possible to reduce atmospheric CO2 by the same technique as envigased for fossil fuel plants if they were fuelled from biomass rather than Coal or Gas.

Dream on we will ever get to the point were we are willing to pay for this stack CO2 removal, let alone atmospheric CCS.

2011-05-10 22:45:39
nealjking

nealjking@gmail...
84.151.43.157

If Hansen's target of 350 ppm is accurate, we will have to do something, even if no further CO2 is added - because we are already above 350 ppm (about 390).

2011-05-14 18:10:35
PeteM
Pete Murphy
pete_murphy65c@btinternet...
86.135.173.247

 

A few years ago I read a book by Kunzig and Broecker  " Fixing Climate "  which suggested they had developed a potentially  economically viable process for extracting CO2  from the atmosphere .  

Does this report  overule this ?

(PS I'm tend to support the motto  - prevention is better than cure )

 

 

2011-05-14 22:21:05
perseus

owlsmoor@googlemail...
188.220.205.42

The word potentially is important here.  I suppose growing trees is potentially economic if all the costs of climate change are allowed for.