[GSBN] Embodied/embedded energy figures

David Eisenberg strawnet at aol.com
Mon Oct 17 09:33:24 CDT 2011


I'd like to chime in with appreciation of the discussion here and to echo
Jim and Tom's observations but to also say that in my experience - as a long
time proponent of the importance of embodied energy here in the US, that it
was the energy efficiency folks who dismissed the importance of embodied
energy continually until the last few years, not those of us involved in
greening the built environment. Their argument was that if you compared
operating and embodied energy, you would see that embodied energy was
insignificant. My argument was that we were talking about a significant
number dwarfed by a huge number, but the size of the embodied energy did not
mean that the embodied energy was not important, just that it was made to
look insignificant by the size of the operating energy. They often used
percentages to compare the two and I would say, okay using that method, what
is the percentage of embodied energy when operating energy is zero? And how
much have you increased the embodied energy in order to get to net-zero? My
view is that that is the bigger issue...we're typically using much higher
embodied energy materials and systems in most of these buildings to get to
low operating energy performance - which amplifies the problem. And the
global warming potential also typically goes way up.

The other aspect of this is the assumption that we will have the affordable
and available energy to continue to build energy intensive buildings the way
we're been doing it. A tenuous assumption at best. Regardless, it would be
great to have more research and better documentation for the spectrum of
natural building materials and systems.

Thanks for the great dialogue.

David Eisenberg



On Mon, Oct 17, 2011 at 2:53 AM, Jim Carfrae <jim.carfrae at plymouth.ac.uk>wrote:

> I would agree with Tom that we are losing sight of the importance of
> embodied energy.
>
> If you compare a well built SB house to the equivalent Passiv Haus they can
> both reduce their energy in use to a similar level.
> But looking at their total energy dept over 60 years, the Passiv Haus
> (built with conventional materials) will have a higher energy dept, with up
> to 40% of its dept tied up in the fabric of the building.
>
> The more you reduce energy in use, the greater the proportion of your
> energy dept over time will be in the materials you use.
>
> As Tom points out it depends on the source of figures you use, but using
> the Bath data a quick comparison of straw and expanded polystyrene is
> interesting:
>
> To achieve the U value of a typical SB wall (0.17 Wm2K) using polystyrene,
> you would need a thickness of 135mm.
> For each square metre of wall at the given thickness of each material:
> The straw has an embodied energy of 9.5 MJ
> The expanded polystyrene has an embodied energy of 419 MJ
>
> So a short and simplified answer to the question 'why use straw?' could be
> 'because the conventional equivalent has over 40 times the embodied energy!'
>
> This is a pretty gross generalisation, but is still food for thought!
>
> I presented a paper called 'The Leechwell Garden House' at the PLEA
> conference in Brussels this summer that discussed this issue. You can
> download a copy from my website, along with other SB related research:
> http://www.carfrae.com/downloads/index.html
>
> Thanks
>
> Jim
>
> J M J Carfrae PhD
> Environmental Building Group
> School of Architecture
> University of Plymouth
> Drake Circus
> Plymouth PL4 8AA
> UK
>
> jim.carfrae at plymouth.ac.uk<mailto:jim.carfrae at plymouth.ac.uk>
> 07880 551922
> 01803 862369
>
> On 17 Oct 2011, at 09:12, Tom Woolley wrote:
>
> Dear all
>
> Here is the link to the Bath database that Bruce couldn't find
>
> http://www.bath.ac.uk/mech-eng/sert/embodied/
>
> However Craig Jones who has done most of the work on this has now moved
> into the private sector and works for "Sustain"
> http://www.sustain.co.uk/
> Craig.Jones at sustain.co.uk<mailto:Craig.Jones at sustain.co.uk>
>
> While I think Craig and Geoff at Bath have done a great job on this, to
> keep the issue of embodied energy on the agenda,
>  it worries me that the ICE database is treated with almost biblical
> respect in many refereed publications.
>
> Bath has never had proper funding for original research on ICE and so much
> of the data has been gathered from here there and everywhere.
> This means that the data provided by many commercial companies has not
> necessarily been independently verified
> Some of us would question figures given for the embodied energy of natural
> materials for instance.
>
> I would be interested to know where embodied energy figures on the agenda
> in other countries ( for something I am currently writing)
> In the UK, organisations like the AECB and the Passiv Haus people are
> pushing the argument at the moment that energy in use is the only thing that
> matters.
> I though we had got rid of this debate years ago but it has resurfaced
>
> While the greenies have been dismissing embodied energy , the commercial
> sector has embraced it recently, a strange reversal
> For instance see the work of Gareth Roberts at Sturgis on carbon profiling
> http://sturgiscarbonprofiling.com/?paged=3
> Its worth downloading their RICS Redefining Zero publication
> While it doesn't say anything about strawbales it does provide a very
> interesting methodology.
>
> We are launching the Alliance for Sustainable Building Products in
> Parliament on November 16th
> I have a one page leaflet about this but I think you cannot add attachments
> to these emails so if anyone would like this please sent an email to my
> personal address
> tom.woolley at btconnect.com<mailto:tom.woolley at btconnect.com>
>
> Tom
>
>
> On 14 Oct 2011, at 19:47, Bruce King wrote:
>
>
> The University of Bath (UK) has the best database I know of, but I can't
> find the link.
>
> Thanks,
>
> Bruce King, PE
> Director of EBNet
> Ecological Building Network
> the art and science of building well
> bruce at ecobuildnetwork.org<mailto:bruce at ecobuildnetwork.org>
> PO Box 6397
> San Rafael, CA 94903 USA
> (415) 987-7271
> follow us on Twitter: @EBNetwork
> blog:  http://bruceking.posterous.com/
>
> On Oct 14, 2011, at 11:37 AM, Chris Magwood wrote:
>
> Hi all,
>
> I'm working on a research paper and I'm trying to find good, reliable
> information on embodied energy (or embedded energy) in building materials. I
> have some good papers from Australia and some stuff from CMHC, but I'd be
> glad to receive suggestions for other sources.
>
> Thanks!
>
> Chris
>
> --
> www.chrismagwood.ca<http://www.chrismagwood.ca/>
> www.endeavourcentre.org<http://www.endeavourcentre.org>
>
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> Tom Woolley
>
> Rachel Bevan Architects
> 80 Church Road
> Crossgar
> Downpatrick
> BT30 9HR
> tom.woolley at btconnect.com<mailto:tom.woolley at btconnect.com>
> 028 44 830988
> www.bevanarchitects.com<http://www.bevanarchitects.com>
>
>
>
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