1. Power generation is possible, but there are better sources and only a small percentage can at present be used this way. Their papers addressed some of the alternative uses.
2. Yes, one would have to get permits to do this and perhaps the case can be made this is carbon sequestration and not disposal. 3. Regarding the methane issue, while the temperature and pressure would allow for hydrate formation (remember the problems with the Deepwater Horizon containment vessel, the "Top Hat?") and there are known hydrate deposits nearby that are actively producing the hydrates via microbial activity (the Bush Hill site), there are other factors that would mitigate against this occurring for the CROPS type disposal scenario or for wood itself. The bottom water above the sediment layer has a relatively high oxygen content. The plant waste and wood also contain high levels of lignocellulose such that the lignin protects the cellulose from attack by the bacteria. Unlike marine snow, this material would take much longer to decompose and wouldn't necessarily produce methane. And, since the disposal areas would likely be subject to intense monitoring, the rate of methane production would be known and the addition of crop/wood waste could be stopped if necessary. Field trials would have to be undertaken first and these would identify whether or not methane or something else is a potential problem. ----- Original Message ----- From: Andrew Lockley To: [email protected] Cc: geoengineering Sent: Friday, September 10, 2010 5:20 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]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
