[GSBN] embodied energy and sequestration

[martin oehlmann]

Dear Tom,

here you have the text which explains the opinion of IPCC and UN-FCC. They distinguish between biogen carbon and geogen carbon like cement/beton and burned lime.
This reference is accepted by the German Governement. They think still there are 3 little pigs building a house ;-)))

It seems to be we are creating a subworld in the big world. Great if there are connected...

Nice day, Martin
3.3.2 Speicherung von CO2 bzw. Kohlenstoff in Produkten 

Der PAS 2050 schlägt vor, die (Zwischen-)Speicherung von CO2 zu erfassen und nach einer vorgegebenen Formel von den Gesamtemissionen abzuziehen (PAS 2050: 2008, p. 8). Beispiele sind Holz in Möbeln, Papier in Büchern (jeweils biogener Kohlenstoff), Zement/ Beton oder gebrannter Kalk (geogener Kohlenstoff). 

Nach dem Verständnis von IPCC und UN-FCC (United Nations Framework Convention on Climate Change) wird die Zwischenspeicherung von biogenem Kohlenstoff nicht als Senke betrachtet. Letztlich stellt das nur eine Verschiebung auf nächste Generationen dar. Gegen eine gesonderte Bilanzierung sprechen auch praktische Gründe – der weitere Lebensweg der Produkte ist schwer vorherzusagen und der (abziehbare) zwischengespeicherte Kohlenstoff ist mengenmäßig meist nicht bedeutend. 

Aus diesen Gründen sollte die Speicherung von biogenem Kohlenstoff nicht vom PCF abgezogen werden. 

  ----- Original Message ----- 
  From: Tom Woolley 
  To: (private, with public archives) Global Straw Building Network 
  Sent: Friday, May 07, 2010 2:19 PM
  Subject: Re: [GSBN] embodied energy and sequestration


  Dear all


  Maybe there is confusion here between cement and lime


  Lime can absorb C02 during carbonation and this can make a small contribution to carbon sequestration over its life in a building


  Cement however does not in most cases as cement works best if it does not carbonate unlike lime. 


  The argument that C02 is stored in concrete is a  bogus argument put about by the cement and concrete industry to try and greenwash cement.
  The carbonation argument seems to be based on the idea that concrete can be crushed at the end of life and that this has some carbonation benefit
  See
  http://www.sustainableconcrete.org.uk/main.asp?page=85


  The C02 is emitted during the manufacture of cement and is not recovered in my opinion . It contributes to fossil fuel energy wastage and global warming
  Even the use of recycled material like ash involves energy though the cement industry have made great strides in reducing this


  Cement manufacture remains one of the highest emitters of C02 in all human activity as alternatives are not being used in many parts of the world


  Pragmattically we probably all use a bit of cement from time to time but it should be avoided if there are better alternatives like lime or earth
  Here is an interesting paper which discusses these issues and compares cement to alternatives


  http://www.springerlink.com/content/56266t21424h4854/


  Calculation of sequestration  in wood straw etc.


  A paper on this is being prepared by David Robson of University of Cumbria and initial findings have been presented to the UK Renewable Building Group
  Several GSBN UK members are part of this group


  This research will be made available when complete and will hopefully provide some hard data on the sequestration contribution of renewable bio based materials


  Tom
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sustainablesources.com/pipermail/gsbn/attachments/20100507/a7eb2350/attachment.htm>