Ron, Ken, and others:
Given that the Lima meeting is in its middle day today, let me push everything aside to write answers to Ron's questions. I am speaking only for myself. 1. Yes, there is only one change, aside from formatting, in the June 1 version of the APS report. We say so on the second page of the preface. As we were issuing the unformatted version at the end of April, David Keith identified a clear mistake in our report, involving the pressure drop per meter for a specific packing material, which we had carried forward from a 2006 paper. Fortunately, one member of our committee, Marco Mazzotti, was an author of that paper. With one of his co-authors, he updated his earlier work with new information from the manufacturer of the packing, additionally found an error in his earlier analysis, followed a hunch that there was an easy fix for us by substituting one packing for another, and we buttoned this up. The new packing is cheaper, but we verified that our initial cost estimate for packing had been so conservative that the new packing actually fit the assumed price better. I am aware at this time of no outright error in our report. People may find some, and if they do I hope they will tell me about them. 2. Item a. In my view, the experts (specifically Keith, Lackner, and Eisenberger) were given adequate time to interact with us. Our project took two years. We established groundrules at the front end that there would be an arms-length relationship and (confirmed more than once) that as a matter of policy we would not learn confidential information. All three presented to us at our kick-off meeting in March 2009, reviewed a draft (along with almost 20 others) in April 2010, and communicated repeatedly with us. I had the personal goal of being sure that the key ideas in their work were understood by our committee and commented upon in our report. Nonetheless, none of the three of them is happy with the result. One comment all three would make is that they would have done the study differently. They would have asked what air capture could cost if one were to assume success in the presence of risk; our committee felt that in the absence of reviewable published data, this was an illegitimate task. We decided to include one cost estimate based on a benchmark design, resulting in a system whose cost is probably quite a lot higher than $600/tCO2, and in the process, by careful attention to methodology, the reader can learn how to think about costs. Personally, I now appreciate (and the reader will too who works through the calculation) that the most underestimated cost factor is the pressure drop as air moves through the contactor, which enters not only as a an energy cost but also through its impact on "net carbon," even for largely decarbonized power. All three experts are working on low-pressure-drop systems for this reason. Item b. I know of no comparable study. We call explicitly for some group to do some comparable analysis of biological air capture: afforestation, biochar, BECS - maybe one study for each. In that instance it will be critical to understand what scale-up looks like: small-scale deployment is cheap and could have major co-benefits. But how much planetary engineering is entailed if one aims for the reduction of atmospheric CO2 by 1 ppm per year for a hundred years - negative carbon on a monumental scale? 3. ASAP means "as soon as possible." I think one needs to be careful with such language. If one is in a car, one can slam on the brakes or brake carefully. Both could be called smallest-possible-distance braking, but the meaning of "possible" would be different in the two cases, with more conditionality in the second case. When Pacala and I wrote the wedges paper in 2004, we identified a societal goal of an emissions rate at mid-century no higher than today's; if restated in today's language, 30 MtCO2/yr in 2061. That goal is now considered timid by many - it is associated with "3 degrees," while the more politically correct "2 degrees" is associated with 15 MtCO2/yr. My view is that we shouldn't choose between these two goals now. We should make that decision in 10 to 20 years, but concentrate now on getting on a new path. But I think it is also important, and will make the activist community more credible, if we concede in some prominent way that the world could overreact to climate change, undervaluing what can go wrong when "solutions" are deployed, from the destruction of forest ecosystems to nuclear proliferation. In short, we want to keep conditionality at the front of our minds, not treat it as an afterthought. We should be suspicious of distractions, and, to my mind, direct air capture is one of these. Air capture is a close neighbor of post-combustion capture at coal and gas power plants, a much cheaper mitigation strategy. This simple fact about technological neighbors tells is to be very careful always to state that near the top of the mitigation agenda for several decades is decarbonizing the global power system. There is something grotesque about pulling CO2 our of the air at one place while pouring it into the air at four-hundred times greater concentration at another place. First things first. The underlying irresolvable argument is political. Is a radical goal (2 degrees) that requires instant comprehensive mitigation best suited to spur action, even when activists widely concede (mostly privately) that the goal is unachievable and has the potential to lead people to throw caution to the winds? Or is a liberal goal (3 degrees) -- more suited to deliberative action, more respectful of the legitimate needs of developing countries, and more matched to the building of coalitions -- a better choice? Which is more likely to lead to our getting started and not having our grandchildren looking at "5 degrees"? I leave the Lima group with a final thought. Is SRM only an emergency strategy? What are the pros and cons of a continuous ground-bass deployment of 1 W/m^2 of stratospheric aerosol negative forcing, as an overall helper on the margin and as a way of learning about larger deployment? Rob From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, June 21, 2011 12:03 PM To: Robert Socolow Cc: [email protected]; [email protected] Subject: Re: [geo] Cost of Air Capture and the APS report Robert and ccs 1. Thanks for the added links and information. Not yet mentioned on this list is that your APS panel changed (added?) only one footnote (#18) - and as near as I can tell - changed no conclusions. Still projecting $600/tonCO2, it seems. 2. As you may have noticed there has been some discussion this list on how we (Society) should be evaluating climate technologies. I do think that groups such as the APS have done and can do a great public service with studies of the type you have performed here (but I know too little of the topic to know if your panel or Keith should be given the higher believability rating). I thank you for taking on a thankless task. Two questions for you, based on my concerns (as at what may happen in Lima, for instance) a. Do you feel that the air capture experts were given adequate time to present to your panel - or might you now do something different procedurally? b. Are you aware of any other similar (highly technical, multiple and presumably un-biased panelists) technology assessment in the works (by professional societies or anyone) for any of the other field(s) of geoengineering? 3 Your proposal with Prof Pacala to use the simplified concept of seven wedges reaching 1 Gt C each in 50 years time (and 25 Gt C each avoided) has been very helpful (unfortunately not yet very well followed). Several questions on that as related to the interests of this list: a. Since we all (?) are trying to get into carbon negative territory ASAP, can you comment on having each wedge grow twice as rapidly so as to get to zero fossil carbon by 2060. This being even longer than Jim Hansen desires, of course - so can you endorse an even shorter growth period for the (roughly seven? or do we need 14 now?) wedges. b. Have you given thought as to what a similar carbon negative wedge split should be on the CDR side? How much BECCS, air capture, ocean deposition. tree planting, Biochar, etc? Does the wedge concept still work as well? At what time point in the 50 year history for the "traditional" Pacala-Socolow wedge growth would you recommend starting the CDR wedges? Soon? c. Is there a way that the SRM technologies fit into a wedge description? Thanks in advance. Ron _____ From: "Robert Socolow" <[email protected]> To: [email protected], [email protected] Cc: [email protected] Sent: Monday, June 20, 2011 8:33:12 PM Subject: RE: [geo] Cost of Air Capture and the APS report Ron and others: I attach .pdfs for the report (revised) and the press release. The links are: Report: http://www.aps.org/policy/reports/popa-reports/loader.cfm?csModule=security/ getfile <http://www.aps.org/policy/reports/popa-reports/loader.cfm?csModule=security /getfile&PageID=244407> &PageID=244407. Press release: http://www.aps.org/about/pressreleases/dac11.cfm The links have not been changed. Rob Socolow From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Monday, June 20, 2011 8:08 PM To: [email protected] Cc: [email protected] Subject: Re: [geo] Cost of Air Capture and the APS report David - Can you provide a link to the revised APS report? (I failed.) Thanks Ron _____ From: "David Keith" <[email protected]> To: [email protected] Sent: Monday, June 20, 2011 4:38:16 PM Subject: [geo] Cost of Air Capture and the APS report Several recent posts have referred to the American Physical Society's report on Air Capture. We posted a critique of the report and in turn the APS released an updated version that-using a post-facto kluge-addressed two of the errors that had identified. The our comments are posted on www.carbonengineering.com the website of our Air Capture startup company, the deep link is here: http://www.carbonengineering.com/wp-content/uploads/2011/05/CE_APS_DAC_Comme nts.pdf. We at Carbon Engineering are self-interested. Of course! But that cuts both ways. We have a huge incentive do to quality engineering that can be brought to market and not to waste our time on stuff that does not make sense. Speaking for myself, I have opportunities to do commercial work on both AC and on biomass with capture (BECCS). And I have access to high quality proprietary engineering and economic analysis of both. If I thought that BECCS was much cheaper than AC then I would not be working on AC. David -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en. -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
