[GSBN] embodied energy comparisons

[Derek Roff]

Thanks, Martin.  Could you clarify a bit about this sentence?  Do the 
sources that you quoted give an explanation?

"cement-based products in contrary are accepted to reduce the PCF 
(product-carbon-footprint) as the CO2 used for production is stored for 
a long time."

What I find confusing, is that production of cement produces a lot of 
CO2 from fossil fuels in mining, processing, calcining, and utilizing. 
It produces/releases a fair amount of sequestered CO2 from the 
limestone during the calcining chemical reaction.  I'm not thinking of 
any point at which "the CO2 used for production" is stored at all.  A 
small amount of CO2 is reabsorbed from the air by finished concrete, 
but what I have read is that this is a tiny fraction, and needs to be 
tiny, to maintain the integrity of the concrete.

So what CO2 storage are they talking about?

Derek

--On Thursday, May 6, 2010 9:24 PM +0200 martin oehlmann 
<moehlmann at wanadoo.fr> wrote:

> Dear all,
>
> however not much response here on this issue...  some possible
> interesting observations in the meantime:
>
> According the perception of IPCC and UN-FCC straw and wood are not
> seen as CO2-sink, yet CO2 neutral, cause of the durability is
> “difficult” to calculate. In contrary cement-based products in
> contrary are accepted to reduce the PCF (product-carbon-footprint) as
> the CO2 used for production is stored for a long time. (source:
> Memorandum Product Carbon Footprint, German Ministry for Environment,
> Nature Protection etc.)
>
> Comment: compliments for the cement lobby, low cost cementbased
> massproduction for housing with a lifespan 30-40 years.
>
> If planted forests get cut after 30 years and seen as a CO2 sink, a
> high quality building which lasts 100 years and longer built with
> natural materials better should be perceived as storage, if the
> intention from IPCC and UN-FCC is to support sustainable
> constructions.
>
> Nice day and all the very best,
>
> Martin Oehlmann
>
> Brittany



Derek Roff
Language Learning Center
Ortega Hall 129, MSC03-2100
University of New Mexico
Albuquerque, NM 87131-0001
505/277-7368, fax 505/277-3885
Internet: derek at unm.edu