The 4-mil plastic weighs 8.7Kg/1000SF. At 3Kg CO2 per Kg plastic, then this results in 26Kg CO2 per 1000SF. Using the revised figures for Akbari et al., 1000SF of whitened roof offsets 8 tonnes or 8000Kg. 26/8000 = 0.3%. If new plastic had to be installed annually for 20 years, without any recycling, the emissions increase to 6% of the total offset. I doubt other sources of CO2 from transportation, installation, disposal, etc. would add significantly to the total. I agree that life cycle costs need to be determined if any of these covers were to be used to generate credits, including the CO2 from methane oxidation.
I have no estimates on the spray on or membrane coatings, other than some of them produce a thicker film which would translate into larger CO2 emissions from production. Due to their long lifetimes, however, I doubt the externalities would be significant. ----- Original Message ----- From: jim thomas To: [email protected] Cc: geoengineering ; Arthur Rosenfeld ; Haider Taha ; [email protected] ; Derek Fiddler ; Jayanty, R. K. M. Sent: Tuesday, December 15, 2009 8:11 PM Subject: Re: [geo] Re: The Nexus of Cows and Roofs Alvia Have you dug up any figures on embedded energy costs (and hence co2 emissions) for white paint/PVC/tio2 and polyethylene production per square meter - i see the industry claims polyethylene has a 1-3 kg co2 carbon footprint per kg of production (depending on density) but haven't checked if that includes disposal .. i don't know how much your membranes weigh but i guess there is something there. That and something on transport of materials and energy sots of applications for thsoe sprayers would be helpful to throw into the calculations. I accept it might be small and with new-build one can argue that there is no additional production since there would have been some sort of cover/paint anyway but if you are proposing basing tradable, countable credits on this 'solution' then it could be additional production and those sort of externalities might all really add up. Maybe Akbari et al have already taken this into account but it doesn't show up in your presentation anywhere. best Jim On Dec 15, 2009, at 11:19 PM, Alvia Gaskill wrote: After extensive revisions and additions, another version of the powerpoint on using roof whitening to generate CO2 and CH4 (as CO2) credits has been prepared and is attached. Dr. Jayanty presented an earlier version in India this month. I would appreciate any comments. Responding to some of the comments received, the statement that cooler (NIR reflective) shingles would cost more than the standard ones came from the Rosenfeld memo to the State Dept. The memo says $2/square meter and I used $2/SF in the previous version, so the actual difference is about $0.18/SF or $180 for a 1000SF roof. The slide in question, no. 45 has been corrected. I haven't been able to confirm this myself, but whether they are more expensive or the same, the cost differential with the plastic sheeting is still quite large. There is something wrong with the way I calculated the offsets for CH4 using the Myhre equations. Anyone who can explain this, please do so. I alternatively calculated the CH4 offsets based solely on the differing lifetimes of CH4 and CO2 in relation to the roof lifetimes. In doing so, CH4 provides for 4 times the offset, so there is a clear advantage to pairing it with roof whitening in a trading scheme. The offsets calculated by Akbari et al. have been reduced by about 20% due to the use of the correct CO2 perturbation lifetime schedule. The photo slides now have captions, one benefit coming out of this study that I now know how to add them. I would also be interested in finding out how the proposals from Art and Hashem were received in Copenhagen. Good luck in your retirement, Art. You've already done your part to brighten up our troubled world, but don't stop now. ----- Original Message ----- From: Alvia Gaskill To: [email protected] Cc: Arthur Rosenfeld ; Haider Taha ; [email protected] ; Derek Fiddler Sent: Friday, November 13, 2009 11:04 AM Subject: The Nexus of Cows and Roofs This presentation was slapped together in <24 hours so don't hurt yourself laughing over the mistakes. The other author, Dr. Jayanty is presenting this in various places in India during November and December, hence the lack of identified locations on this draft. It is aimed for an audience of university students, so I included all the background information about global warming. The picture slides aren't labeled. Slide 37 shows an aged white roof for a Sam's Club in Durham, NC, 2009. Slides 50, 51 show elastomeric coatings applied or being applied to roofs. Slide 57 shows the 4-mil plastic next to the 8-mil on a tennis court, Slide 58 shows 4-mil alone. Slide 59 4-mil on shed roof. Slide 60 Mylar film with 4-mil on top and Slide 61, 16-mil next to 4-mil. I also didn't explain that the current trading price of carbon dioxide on the European exchange is around $25/tonne (as the dollar deteriorates, the value goes up--be careful what you wish for). Call it bad karma or whatever, my own roof began leaking yesterday while wrapping this up. A paper is in preparation going into more detail about this work. I would also recommend that the white plastic be compared with the other roof treatments on government buildings ASAP to see if I'm correct about the cost advantage. AC is used nearly the year-round in parts of FL, AZ and Calif. and it's almost summer in Australia. Hint, hint. Comments appreciated as this is a work in progress and we can change the future, FlashForward or not. Alvia Gaskill Expert on roofs, but not cows -- 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. <Fast Tracking Energy Savings and Methane Carbon Credits.ppt> Jim Thomas ETC Group (Montreal) [email protected] +1 514 2739994 -- 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.
