[Strawbale] re: Embodied Energy, Carbon research of Big Bales...

Mark BP / Low Energy Design Ltd mark at lowenergydesign...
Mon Nov 5 05:12:13 CET 2007

Just had a look at the Athena site.  The free spreadsheet available 
there is pretty limited in its scope - haven't looked at the larger 
package for which you have to pay a few hundred dollars.  Also seems to 
be applicable to the north American market only.  My other worry arises 
from the list of sponsors.... - and from the fact that at least one of 
their packages was developed specifically for Green Globes, an 
assessment programme sponsored by north American big forestry and cement 
companies who didn't like the requirements of tougher programmes like LEED.
But, that said, I can't find anything else that's out there in 
user-friendly form.

Mark BP / Low Energy Design Ltd wrote:

> Max, I look forward to the results of your work.
> I did a very simple analysis of comparative embodied energy as part of 
> my thesis 2 years ago - strawbale construction came out considerably 
> better than any of the construction methods which are "mainstream" in 
> Britain.  I'm glad that someone is committing to a more detailed 
> analysis regime - a tool by which we can compare lifecycle energy 
> costs of different options at the design stage would be most welcome.
> Re what you actually include when calculating embodied energy:  it 
> depends on local practice.  Would the straw stems normally be cut 
> anyway? (as opposed to just chopping off the grain heads) - if yes, 
> then you don't need to include that energy cost.  Would they normally 
> be baled anyway?  - if yes, then you don't need to include that one 
> either, or maybe a differential between the energy costs for a baling 
> strategy convenient to the farmer and a baling strategy that yields 
> good building bales.  For nearly all bales in Britain (where I used to 
> live), and for a high proportion (maybe even a majority) in the 
> Canadian prairies (where I live now), the only energy costs 
> appropriate to include for the bales themselves are for transport to 
> site and for any use of power tools in construction of the bale walls 
> (e.g. in precompression, or for spraying of plaster).
> But it is also important to do this on a whole-building basis - 
> thicker walls result in larger roof and floor assemblies and hence in 
> higher embodied energy figures for those parts of the building.
> And I think I can predict pretty confidently that in a bale building 
> the embodied energy from the strawbales will be dwarfed by that from 
> other materials, especially cement.  So to my mind a really useful 
> tool would pay more attention to concrete and stucco than to bales.
> The other issue that complicates this when you get to carbon intensity 
> - at least here in the prairies - is just how much carbon is 
> sequestrated by digging straw into the ground.  Our provincial 
> government has made rather large and grandiose claims for this 
> practice as part of their climate change strategy, and I am - to say 
> the least - sceptical (not least because it enables them to evade the 
> responsibility of developing a truly sustainable energy policy, which 
> would involve them having to sometimes say no to the coal industry and 
> to those in the provincial power company who don't like thinking in 
> new ways).  If there are any agronomists on this list who can shed 
> light on this issue, I at least would be grateful.
> I wasn't able to find OPTIMIZE via CMHC's labyrinthine website.  
> However, I did find this:  
> http://www.cmhc-schl.gc.ca/en/inpr/bude/himu/coedar/upload/Sustainable-Building-A-Materials-Perspective.pdf 
> ,
> which makes reference to this:  
> http://www.athenasmi.ca/about/lcaModel.html .
> Not having had a proper look at either the former document or the 
> latter site (and LCA model), I can't comment on their quality, but 
> they're worth knowing about at the very least.
> Mark Bigland-Pritchard
> Borden, Saskatchewan, Canada
> Robert Tom wrote:
>> On Sun, 04 Nov 2007 13:14:03 -0500, Max Vittrup Jensen 
>> <max at permalot...>  wrote:
>>> It so happen to be that Canadian François Gonthier-Gignac and I are 
>>> in  process of developing a tool to promote cleaner ways of building 
>>> through  optimizing Embodied energy, energy efficiency and costs in 
>>> residential  housing.
>> Some time ago (10 years ?) through the auspices of Canada Mortgage &  
>> Housing Corp.
>>     http://www.cmhc-schl.gc.ca
>> there was a LCA software program developed called "OPTIMIZE" that 
>> enabled  one to model the embodied energy of a proposed design, as 
>> well as the life  cycle costs and other things like replacement costs 
>> at the end of the life  cycle, water consumption, waste generation, 
>> ease of re-use/recycling of  the deconstructed building materials and 
>> if I recall correctly, potential  for off-gassing of VOCs and actual 
>> dollar costs.
>> I've gone through a number of hard drives since then so I can't pull 
>> up  the actual printout results (about 10 pages per run I think) at 
>> the moment  but if you contact CMHC, they should be able to provide 
>> you with  documentation.
>>> put to the task of coming up with  an amount of kilo joule 
>>> whichgoes  into 1 single big bale, my approach would be to find out 
>>> how many big  balesan average (European) baling machine make per 
>>> hectare, and find out  the liters ofdiesel consumed. These figures 
>>> should give the individual  answer.The LCA (Life Cycle Analysis) 
>>> tool then also need  some figures  for transport to storageand to site,
>> Typically, the figure for embodied energy would include the energy  
>> consumed for transport to storage and to the site, as well as the  
>> "production energy" for harvesting and baling operations and any 
>> other  energy consumed during the process of construction to get the 
>> bales in  place in the walls.  You will this defined in:
>> Cole, Raymond J. and Rousseau, David. 1992.
>> Environmental auditing for building construction: energy and air 
>> pollution  indices for building materials.  Building and Environment 
>> 27, #1 (January)
>> Obviously, since big bales require the use of heavy machinery at each 
>> and  every stage of their handling, the embodied energy per kilogram 
>> of straw  will be greater than that for "regular"-sized two and three 
>> string bales  so the figures provided for the EE of straw in the 
>> references provided  earlier in this thread, will not apply.
>> Also, I'm pretty sure that the EE numbers in the sources mentioned 
>> were  compilied by looking at Canadian and Australian  
>> farming/transportation/building practises which I suspect, would be  
>> noticeably different than those for most European locations, mostly 
>> due to  scale.
>> Even here in Canada, one will see quite a difference in scale between 
>> 2  different provinces within the same country (ie Prairies vs 
>> Central  provinces.)
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