An interesting paper, but one which nonetheless does not consider the possibilities offered by Biomass Energy with Carbon Capture & Storage. If you can float crop waste down the Mississipi for sinking, you can float it down in dry bags for burning.
Typically, CCS knocks about 20% of the energy output of a power plant (from memory). So, it still looks like it's worth burning the crop waste to recover the energy, then sequestering the CO2. (Although the 20% may rise if the carbon efficiency of the generation process is lower for crop waste). Further, the paper's comparison with natural gas isn't terribly helpful, as it's a particularly scarce fossil fuel. Coal would make a more realistic comparison, in the long term - dramatically reducing the benefit claimed. One further point is that sequestering CO2 rather than crop waste doesn't carry any risk of clathrate formation. Perhaps someone could do me the courtesy of pointing out any flaws in my analysis? A On 12 September 2010 21:55, Marty Hoffert <[email protected]> wrote: > Maybe the attached paper will help: An early approach explaining why, > fundamentally, it's better to bury crop residue biomass than to burn it for > energy. > > Marty Hoffert > Professor Emeritus of Physics > Andre and Bella Meyer Hall of Physics > 4 Washington Place > New York University > New York, NY 10003-6621 > > NYU Phone: 212-998-3747 > NYU Fax: 212-995-4016 > Home Phone: 516-466-9418 > Home Fax: 516-487-0734 > Cellphone: 516-972-4779 > Email: [email protected] > Web page: http://www.physics.nyu.edu/people/hoffert.martin.html > > > Andrew, > > > > All of these arguments were answered last year when the paper came out, but > apparently you did not digest them then, so I will repeat, briefly. Burning > biomass for electricity or making ethanol avoids fossil fuel carbon > emissions = 30% of the starting biomass carbon. Biomass is a poor fuel, > better to bury it. Please read the paper. Or is there something about 3>1 > that you don't understand? > > > > Biomass could be co-fired with coal to generate power and if the CO2 from > that process were captured the overall C sequestration and avoidance > efficiency would be about 115%, but will plant operators divert generating > capacity from coal to the poor fuel, biomass? > > > > Methane from biomass is unlikely to be a problem because anaerobic > processes in the ocean is dominated by sulfate reduction. Thus, methane > diffusing from within the stacked bales would be oxidized by sulfate > reducers. Please take the time to educate yourself on these matters before > you post ill-informed opinion to the group. > > > > BE > > > > = Stuart = > > > > Stuart E. Strand > > 490 Ben Hall IDR Bldg. > > Box 355014, Univ. Washington > > Seattle, WA 98195 > > voice 206-543-5350, fax 206-685-9996 > > skype: stuartestrand > > http://faculty.washington.edu/sstrand/ > > > > *From:* [email protected] [mailto: > [email protected]]* On Behalf Of* Andrew Lockley > *Sent:* Friday, September 10, 2010 2:21 PM > *To:* [email protected] > *Cc:* geoengineering > *Subject:* Re: [clim] Re: [geo] Carbon sequestration workshop Sep 9-10, > Heinz Center, Washington DC > > > > Isn't the main problem with CROPS that you're burying something which is > flammable, at the same time that similar flammable materials are being dug > up elsewhere ? There seems little point collating and transporting all that > crop waste, then just throwing it into sea, when you could generate power > with it instead. > > Ironically it might be more efficient to use the electricity so generated > to power carbon air capture technologies. With a bit of luck there would > still be enough electricity left over to sell, even after you'd captured > more carbon than was in the original crop waste. > > A second problem is, as previously mentioned, the legal restriction on > dumping at sea. > > Finally, an issue which appears not to have been studied in detail is the > risk of the CROPS scheme causing large gas hydrate deposits, which are then > later destabilized as the oceans warm. This could potentially create a > forcing far greater than that of the avoided CO2. > > Hopefully someone can calculate these effects, as I don't know how to. > > A > > On 10 Sep 2010 20:10, "Alvia Gaskill" <[email protected]> wrote: > > I think there is some confusion about the term "ventilation rate" as it is > used here. The work that apparently forms the basis for the 250-year > ventilation rate for the GOM discusses it in terms of how long the deep > water in the Gulf stays there before being carried back out into the > Caribbean Sea. If you look at Figure 15 from the linked reference, it shows > that the deepest water exits over the Yucatan Sill at 2040 meters. What > happens to it after that is unclear. The ventilation rate referred to here > is how long it takes the water to make it out of the Gulf, not how long it > would take CO2 from decomposing bales of crop waste to re-enter the > atmosphere. The relatively high oxygen levels at the bottom, around 5 mg/L > could accelerate oxidation of the waste, but over long periods of time it > would probably become buried in sediment and would be in an anoxic > environment, also limiting any transport of CO2 to the surface. So I would > encourage you to research this a little more before giving up on the Gulf of > Mexico. > > > http://oceanografia.cicese.mx/personal/jochoa/PDFS/Rivas_etal_JPO_2005.pdf > > ----- Original Message ----- From: "Stuart Strand" < > [email protected]> > To: <[email protected]>; <[email protected]>; "geoengineering" < > [email protected]>; <[email protected]> > Cc: <[email protected]> > Sent: Friday, September 10, 2010 12:50 > Subject: RE: [clim] Re: [geo] Carbon sequestration workshop Sep 9-10, Heinz > Center, Washington DC > > > > > After our publication it was pointed out to me that the ventilation rate of > the Gulf of Mexico is... > > -- > 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]<geoengineering%[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]<geoengineering%[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]<geoengineering%[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. 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