[GSBN] Embodied energy comparisons: SB vs Stick-built

Derek Roff derek at unm.edu
Sun Feb 15 00:19:57 CST 2009


I'm a bit concerned by what I understood from the summary.  It seems 
to say that it is better/greener to build a bigger house, at least 
one with more materials, such as straw plus wood frame.  While straw 
and wood both contain carbon, I would be surprised if you could get a 
2x4 to a job site in an industrialized country without 
generating/releasing a lot more carbon into the atmosphere than is 
contained in the board.

Another aspect of the calculation should be, "What would have 
happened to this material if I hadn't used it in my house?"  The 
average 2x4 would still be a tree, which would be much better for the 
environment.  Straw is a little harder to pin down, since it is a 
by-product of growing grains.  If we compare building with straw to 
burning it, building has a great greenness advantage.  If we compare 
building to leaving the straw in the field, the difference is much 
smaller, and might favor leaving the straw in the field.  In any 
case, we know that straw would not live on for another season.

I believe that smaller is better/greener, when it comes to building 
design, and a larger perspective may be needed in analyzing the 
importance of carbon sequestering.  Have I misunderstood Andrew's 
summary?

Derelict

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


--On Saturday, February 14, 2009 8:34 PM -0800 John Swearingen 
<jswearingen at skillful-means.com> wrote:

> Very interesting!~
>
> I know some people have gotten 'grants' from carbon credits for
> sequestering CO2.
>
>
> On Wed, Feb 11, 2009 at 8:30 PM, Graeme North
> <graeme at ecodesign.co.nz> wrote:
>
>
> Here is Andrew's interesting reply
>
>
> best
>
>
>
>
> Graeme
> Graeme North Architects
> 49 Matthew Road
> RD1
> Warkworth
> tel/fax +64 (0)9 4259305
>
> graeme at ecodesign.co.nz
> www.ecodesign.co.nz
>
>
>
> On 12/02/2009, at 12:57 PM, Andrew Alcorn wrote:
>
>
> Hi Joyce
>
>
> As Graeme says, I am nearing completion of a PhD thesis that looks
> at
> this question. Numbers are not quite complete yet, but the short
> answer is that the embodied energy is not such an important
> consideration, in terms of minimising environmental impact, as
> embodied CO2 emissions (ECO2) is. To build a house that has an
> (annualised) per-capita CO2 emission that is within what the planet
> can absorb, the only way possible is to incorporate as many low ECO2
> materials as possible. (Basically, plant materials, which have a
> 'negative' CO2 emission value.) And the only way to do that, simply
> considering the mass of stored carbon required, is to use straw
> bale
> as the insulating material. Of course, combining that with a stick
> frame adds even more stored carbon.
>
>
> So, if one is asking the question "What is better, stick frame of
> straw bale?", and one is asking this question from the point of view
> of minimising environmental impact (which, presumably, is why its
> framed in an embodied energy way) the answer is "Use both together".
>
>
> As far as actual numbers go, that's a "How long is a piece of
> string?"
> question. What size house? Is it completely load-bearing straw bale,
> or hybrid load-bearing and infill? Or just infill? What sort of
> cladding and lining? What are the exact design details? One would
> have
> to know the answer to all these (and other) questions to be able to
> do
> actual numbers.
>
>
> Anyway, the actual numbers for embodied energy would be an answer to
> the wrong question. Fortunately, the rule of thumb answer (to the
> "What is environmentally best?" question) is very simple: stuff as
> many plant materials into your design as you can.
>
>
> A judicious amount of mass is helpful too, of course, but by and
> large
> this is a lesser consideration that maximising stored carbon.
> Obviously, the usual strategies for minimising operating energy (and
> hence CO2 emissions) are important to incorporate too. The magic
> allowable CO2 per-capita number can't be reached just by using
> straw
> bale for insulation: you also have to use solar hot water, and
> reduce
> lighting, refrigeration and appliance load too. Oh, and minimise
> surfaces that have to be painted - over the years paint,
> surpisingly,
> amounts to a lot of embodied energy and CO2 emissions.
>
>
> I am happy for my email (jandrew.alcorn at gmail.com) to go out, and
> any
> part of this email too, if you want. Obviously there is much more
> to
> say, and I expect people may ask questions, like "Why is ECO2 more
> important than embodied energy?" The anser to ALL those question is
> what my PhD is about. (You can read it in a few months.) In the
> meantime, people may want to download a report of mine here:
> http://www.victoria.ac.nz/cbpr/documents/pdfs/ee-co2_report_2003.pd
> f
> It doesn't include earth of straw bale. The values for those are
> attached.
>
>
> Best regards
> Andrew Alcorn
>
>
>
>
>
>
>
>
>
>
>
>
> 2009/2/12 Graeme North <graeme at ecodesign.co.nz>:
>
>
>
>
>
> HI Joyce - info is scant on this but there is a researcher in NZ
> doing this
> sort of work for  PhD though -
> I've copied this through to him to  see if he is OK about his email
> being
> available to others  hopefully he has these figures
>
>
> best wishes
> Graeme
> Graeme North Architects
> 49 Matthew Road
> RD1
> Warkworth
> tel/fax +64 (0)9 4259305
>
>
> graeme at ecodesign.co.nz
> www.ecodesign.co.nz
>
>
> On 11/02/2009, at 12:27 PM, Joyce Coppinger wrote:
>
>
> Didn't get any replies on this one when I sent it out earlier so am
> resending to see if anyone has any ideas of a source.
> Can anyone suggest the best resources (past and present) to find
> technical
> information on embodied energy of straw bale vs. stick-build
> structures.
> Thanks
> Joyce
> -------
> Joyce Coppinger, Managing Editor
> The Last Straw journal
> GPFS/TLS, PO Box 22706, Lincoln NE 68542-2706 USA
> 402.483.5135, fax 402.483.5161
> <thelaststraw at thelaststraw.org>
> www.thelaststraw.org
>
>
> _______________________________________________
> GSBN mailing list
> GSBN at greenbuilder.com
> http://greenbuilder.com/mailman/listinfo/GSBN
>
> <EE and ECO2 for Adobe - SB - StrawClay.xls>
>
>
>
>
> _______________________________________________
> GSBN mailing list
> GSBN at greenbuilder.com
> http://greenbuilder.com/mailman/listinfo/GSBN
>
>
>
>
>
> --
> John Swearingen
>
> Skillful Means
> www.skillful-means.com



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




More information about the Gsbn mailing list