02 September 2009

Air Capture in the Royal Society Geoengineering Report

The UK Royal Society committee on geoengineering has put out a report (PDF) that reads, well, like it was put together by a committee. But it does say some very interesting things about air capture:
Air capture is an industrial process that captures CO2 from ambient air producing a pure CO2 stream for use or disposal. There is no doubt that air capture technologies could be developed . . .
The Committee expresses considerable ignorance about the costs of air capture, simply calling them "high." Somehow the Committee was either unaware of or chose to ignore (I'm not sure which option is worse) the only peer-reviewed paper that compares to costs of air capture to other approaches to mitigation (i.e., as expressed by IPCC and Stern):

Pielke, Jr., R. A., 2009. An Idealized Assessment of the Economics of Air Capture of Carbon Dioxide in Mitigation Policy, Environmental Science & Policy, Vol. 12, Issue 3, pp. 216-225.

Funny how that sort of thing seems to happen a lot in climate science., but I digress. The report then has this very interesting nugget:
Proposals for new methods [of air capture] are still appearing (confidential submissions received) and it is very likely that substantial cost reductions are possible in future.
So let's summarize what the Royal Society report says: Air capture is undoubtedly technologically feasible, it is "very likely" that "substantial cost reductions are possible," and "with relatively low environmental impacts and low risk of unanticipated consequences."

So then why hasn't air capture occupied a more central role in climate policy discussions? The Royal Society report suggests an answer to this as well:
Already, the politics of geoengineering are complex and contested, and the positions taken by scientists and other analysts may interweave policy preferences with technical judgements. . . Differences in professional and personal values may therefore play a significant role in the evaluation of geoengineering options relative to conventional mitigation and adaptation. The very discussion of geoengineering is controversial in some quarters because of a concern that it may weaken conventional mitigation efforts, or be seen as a ‘get out of jail free’ card by policy makers . . .


  1. I read your paper on the air capture of CO2 and I find the sources you use for the cost estimates of capturing CO2 way too optimistic. As you say yourself, there have been no pilot plants build to base a cost estimate on. They have build pilot plants for capturing CO2 from coal plants and there is a recent paper of the costs of capture costs. "Realistic Costs of Carbon Capture" by Mohammed Al-Juaied and Adam Whitmore. I frankly think their estimates are too low, but the number they come up with are from $30 to $50/tCO2, which is $110 to $180 ton of carbon. Keep in mind that this is a flue gas which has over 100,000 ppm of CO2, not 400ppm like air does. Given that, only the $500 a ton estimate is even slightly plausible.

    Also I'd like point out that the Chinese are building nuclear power plants for less than 2,000 per KWh or 2 billion per GWh. That means that for 1 trillion a year we would get 500GW of carbon free power. Keep in mind that nuclear power plants are income producing assets, so after 20 years the whole construction system would be self financing.

    In 30 years we will have retired all our coal and natural gas powered electric plants. If we don't have a practical electrical vehicle by then, then we can build nuclear plants to produce ammonia for a vehicle fuel.

  2. Joel-

    Thanks for these comments. I used a wide range of published estimates to account for the fact that there are different views on costs. I do not adjudicate between them.

    But do note that the conclusions of my paper are insensitive to the cost range that I use and probably not even to a doubling.

    I'll track down that paper, thanks for the pointer.