"This report explores direct air capture (DAC) of carbon dioxide (CO2) from the atmosphere with chemicals. DAC involves a system in which ambient air flows over a chemical sorbent that selectively removes the CO2. The CO2 is then released as a concentrated stream for disposal or reuse, while the sorbent is regenerated and the CO2-depleted air is returned to the atmosphere. To guide the reader to an understanding of the factors affecting costs, a benchmark system is introduced that could be built today. With optimistic assumptions about some important technical parameters, the cost of this system is estimated to be of the order of $600 or more per metric ton of CO2. Significant uncertainties in the process parameters result in a wide, asymmetric range associated with this estimate, with higher values being more likely than lower ones. Thus, DAC is not currently an economically viable approach to mitigating climate change. Any commercially interesting DAC system would require significantly lower avoided CO2 costs, and thus would likely have a design very different from the benchmark system investigated in this report. This report identifies some of the key issues that need to be addressed in alternative designs."
http://www.aps.org/policy/reports/popa-reports/loader.cfm?csModule=security/getfile&PageID=244407 Earth to physicists: natural, direct (biogeo)chemical air capture already consumes in net >55% (>16GT/yr) of anthro CO2 emitted to the atmosphere and does so for free (OK, there are environmental costs like ocean acidification). Suggested moral of the story - follow nature's lead and do not require CDR systems to make costly and risky concentrated CO2 as the end product. - Greg -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to geoengineering@googlegroups.com. To unsubscribe from this group, send email to geoengineering+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
