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Correcting Miller, et al [2011] (open letter of support)

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  • dave santos
    Cristina Archer Ken Caldeira Dear Cristina and Ken, A close review of Miller, et al s Jet stream wind power: little power, large impact  2011 paper, and a
    Message 1 of 1 , Mar 3, 2012
      Cristina Archer
      Ken Caldeira
      Dear Cristina and Ken,
      A close review of Miller, et al's "Jet stream wind power: little power, large impact" 2011 paper, and a rereading Archer and Caldeira 2009, "Global Assessment of High Altitude Wind Power", cited in Miller, leads me to object that you were very unfairly misrepresented. Miller 2011 misleadingly stated that you "estimated the potential of jet stream wind power to be " roughly 100 times..."...". when in fact no such claim of "potential" was made, but only a preliminary purely illustrative estimate in Roberts, et al, 2007 was cited. Miller compounds the error in mixing its maximal sustainable jet stream energy extraction estimate total of 7.5TW with old total atmospheric energy estimates, falsely attributing to you an estimate of "maximal extractable wind power" of 1700TW (a number Miller concocts), when you never made any such estimate of maximal extractability. Miller's sloppiness makes it wrongfully appear as if you committed a scientific error of more than two orders of magnitude!
      Your 2009 paper was a cautious work, a classic of sorts, and very instructive to the AWES development community. You properly emphasized lower-level winds as having primary technological potential; a picture far more balanced than Miller's sensational implications; which made the public narrative read like failed science heroically corrected. Its unfortunate how this hyperbolic attack on a straw-man grabbed headlines. It would have sufficed for Miller, without overstatement, to point out a general ambiguity in many earlier discussions, between instantaneous power and sustainable extraction. No one ever proposed what the world needed was hundreds of times more power, while killing the gobal ecosystem, as Miller seemingly impugns.
      Miller 2011 made another preposterous assertion, that its conservatively calculated and possibly accurate jet stream sustainable extraction maximum of 7.5 TW represents "a very limited potential of jet streams to contribute to human energy needs". If this is the worst case, that's still quite close to all that humanity would need, given sustainable population levels and ongoing advances in energy efficiency and conservation ethics.
      Such grim spin against upper wind seems more worthy of Clean Coal or Nuke Lobbies, rather than MPI. In fact Miller 2011 was promptly exploited by an anti-green meat-industry front group, as a pure feel-good story. Who knows what other know-nothingist social mischief and reputational harm to the infant AWES sector may result. The net impression of Miller 2011, against a preponderance of independent data, is a general disregard for the general upper wind resource (wind higher than wind towers), which is hardly confined to upper jet streams. The very idea of Airborne Wind Energy, as better than most alternatives, seemed put into doubt. 
      Miller 2011 nevertheless makes a scientific contribution in shining light on the regeneration rate of atmospheric kinetic energy. Although reviewer, Kirk-Davidoff, did not directly question Miller's shabby characterization of earlier work, he displayed exceptional insight and knowledge into AWE, and considerably undermined the worst distortions in Miller's assumptions, on logical factual grounds. There is a healthy middle ground in this scientific discourse, but its not Miller 2011; Archer and Caldiera 2009 stands as the most even consideration of the subject to date. We go where the best science leads.
      A reasonable conjecture is that AWES technology can both make clean energy while also serving to offset a badly overloaded geostrophic energy well caused by anthropogenic warming. AWES technology seems suited for potential geoengineered mitigation of adverse climate changes, since it can in principle powerfully manipulate climate. If the maximal extraction rate ever does prove severely limiting, and a desperate need to avoid CO2 emissions trumps the trade-offs, it may even be possible to enhance the atmospheric kinetic regeneration rate, if we find the right dynamical sensitive-input channels. Its interesting to note that air traffic has for decades opportunistically mined the major jet streams for tailwind.
      The flaws in professionalism in Miller 2011 are merely distractive. The rapidly advancing atmospheric science, and dependent engineering, is not nearly so unpromising as Miller purports. The AWES R&D community remains grateful for your foundational work and eagerly awaits your rebuttals of the unfair attacks and future contributions,
      dave santos
      KiteLab Group
      AWEIA Advisory Board
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