[GSBN] Embodied energy comparisons
Bruce King Ecobuild
bruce at ecobuildnetwork.org
Thu Feb 19 22:45:32 UTC 2009
A note on transportation energy, of which Andrew is a bit dismissive.
I was also dismissive, until I did a calculation for a specific job
(my report excerpted below in red after my signoff tag). I had
assumed that reinforced concrete was so energy intensive that any- and
every-thing should be done to minimize its use (no easy task here in
shaky California).
What I found was that I was not only wrong, but VERY wrong.
Transportation energy was HUGE, at least when discussing the movement
of heavy stuff (earth and rock) into and out of a dense urban area
(ie, pretty far, and by truck). My simplified conclusion is to
confirm what is now enshrined in various green building standards such
as LEED: keep it local. That axiom becomes more true the heavier the
material is, and conversely less so with light materials. If the best
instant hot water heater happens to be made on the other side of the
world, go ahead and get it, no big deal. If, however, you're talking
about moving dirt, or the heavy structural and finish materials, then
localize vigorously.
Here in the USA, we routinely ship framing lumber in great quantity
over a thousand miles to its sales and use point, such as where Derek
lives in New Mexico. In San Francisco, we import gravel -- GRAVEL --
a thousand miles from British Columbia for our concrete. The system,
in other words, is massively dependent on cheap oil. That maybe made
sense for our parents' generation, but not for ours, and certainly not
for all of those generations -- of all species -- yet to come.
My two cents. I really appreciate everyone's posts. This is no
simple subject, but we do need to think these things through.
Thanks,
Bruce "a still vigorous local" King
(415) 987-7271
bruce-king.com
************************************************************
. . . the foundation discussion of a drilled pier system or not
resurfaced last week as excavation and site clearing began. We have
always shown drilled piers in the drawings where the structures are
over an appreciable amount of fill, but decided -- after much
deliberation -- to omit piers in the more stable, "cut" portions of
the foundation. I had led the charge away from piers on the
assumption that the saved concrete and rebar amounted to the greener
way to go; Mark Baumann and Andy Murray [geotechnical engineers]
tentatively concurred, and we crafted a foundation that worked in
every sense of the word, based on that assumption. We were operating
on instinct and judgement, as no one had ever (to our knowledge) ever
even tried to make any sort of apples-to-apples comparison for
something like this -- at least from an ecological perspective. The
resulting design, as is currently shown on the drawings, requires the
overexcavation and export of a three foot layer under the cut areas,
which volume must then be backfilled with imported, compacted baserock.
Spurred by recent onsite discussions, Mark and I set out to put
numbers to this. Specifically, we worked with the excavator and
concrete contractor to determine the dollar and carbon costs that
would be associated with a switch to an all-piers/no-overexcavation
foundation.
We were very surprised.
It turns out that eliminating the 800 cubic yards of overexcavation/
backfilling, and adding about 40 short (eight feet deep) drilled piers
(21 cubic yards of reinforced concrete), has the following effects:
1) Dollars
Save about $100,000 in excavation, export and import costs. Spend an
additional $35,000 for drilled piers.
Net savings $65,000
2) Carbon emissions (figures taken from multiple cross-checked
sources, e.g., EPA)
Save 70,000 pounds of carbon (!!!) associated with burnt diesel fuel
for excavation, export and import costs (3120 gallons of fuel at 22+
pounds of carbon per gallon). Spend (emit) an additional 8400 pounds
of carbon for drilled piers (21 cubic yards at 400+ pounds carbon per
cubic yard).
Net savings 61600 pounds of carbon
************************************************************************
On Feb 19, 2009, at 12:11 PM, Graeme North wrote:
> More from Andrew
>
> Interesting notion of Andrew's that local doe not matter - I think
> it really does matter for reasons of building local economies and
> resilience, and for shortening local feedback loops - using a
> distant PVC plant to make your stuff does not seem justifiable to me
> in any other terms expect those Andrew puts forward below - there's
> more to our choices than carbon storage
>
> By the way - trees are not nearly as good at carbon storage as
> healthy pasture which stores carbon in the soil - (which it seems is
> where most of the carbon in the world is stored). So much for
> carbon guilt credits by asking someone somewhere to plant a tree for
> you - especially when good pasture is used for the plantings unless
> in a very integrated holistic system of husbandry.
>
> No easy answers
>
> Graeme
> Graeme North Architects
> 49 Matthew Road
> RD1
> Warkworth
> tel/fax +64 (0)9 4259305
>
> graeme at ecodesign.co.nz
> www.ecodesign.co.nz
>
>
> Begin forwarded message:
>> From: Andrew Alcorn <jandrew.alcorn at gmail.com>
>> Date: 19 February 2009 8:14:41 PM
>> To: Graeme North <graeme at ecodesign.co.nz>
>> Subject: Re: [GSBN] Embodied energy comparisons: SB vs Stick-built
>>
>> Hi Graeme
>>
>> Joining the list sound sensible... I did use to be on it, or it's
>> ancient equivalent, over a decade ago.
>>
>> Andrew
>>
>> Hi Tim
>>
>> All good ideas - your list. Unfortunately, intuition isn't a reliable
>> indicator of sustainability performance. Even after years of work in
>> this field, mine's been seriously caught out more than once.
>>
>> Straw bale works, even with more concrete footing and more roof. Of
>> course, a timber floor is better again.
>>
>> As a long-time embodied energy researcher, I feel entitled to
>> proclaim
>> that embodied energy is not the best way to measure sustainbility. It
>> has its uses - its good in making comparisons. Actually, money is
>> pretty good, but that requires more work to be able to say exactly
>> how
>> good. Money captures lots more aspects of the (damaging) human
>> enterprise than energy does. Teddy Goldsmith (The Ecologist) captured
>> this when he declared that the environment will not be saved until
>> the
>> economy collapses. But that all opens another, larger, can of
>> worms...
>>
>> Measureing performance in a whole-wall way is a good idea. But,
>> actually, you need to do it in whole-house way. That's when you find
>> stuffing as much carbon-storing material in as possible is the best
>> strategy.
>>
>> Small needs to be related to the number of occupants. If you go
>> *slightly* bigger, but include another person into the household,
>> that's better. Comparing houses on a per-capita annulised basis is
>> the
>> only reliable way I know of to make accurate comparisons.
>>
>> Longevity is important. If you can get each item in the house to last
>> longer, then you use fewer resources to do repairs and maintenance
>> over the life of the house. Hence, materials that don't need painting
>> are good. The exception to this rule, curiously, is carbon based
>> materials (timber and SB). If you replace them at more frequent
>> intervals, and carefully bury the removed items, then over the life
>> of
>> the house you end up storing more carbon in the ground, which means
>> there's less in the atmosphere.
>>
>> Another good strategy (which I know will generate a lot of indiganant
>> hot air) is to use asa many plastic products as you can bear.
>> (Personally I detest the stuff and don't use it for anything.) The
>> reason is that plastic represents carbon fossil fuels that get turned
>> into stuff, instead of being turned into transport fuel and burnt,
>> and
>> then re-buried. That is, the carbon comes out of the ground, then
>> after a few years goes back into the ground, without having been
>> turned into atmospheric CO2. Basically, its better for the oil-and-
>> gas
>> stream to be, as much as possible, diverted to solid objects that get
>> re-buried. But, only use plastic things when you can't use wood.
>> Using
>> wood means a lower atmospheric CO2 level than using plastic does.
>>
>> Looking after people is a good idea, but, actually, the planet
>> doesn't
>> care if a few more people die from cancer because of poisonous
>> materials, so its hard to rate low-toxicity materials as high as
>> minimising climate change effects. Which brings us to another can of
>> worms...what/who are we trying to be good sustainable citizens for -
>> human beings, or other species? Humans are REALLY bad for
>> bio-diversity, generally. (This is a question I put to my students.
>> Often the answer I get isn't the same as the one I get from ordinary
>> folk.)
>>
>> No. Don't adjust materials to what's locally available. Use what is
>> going to give the best life-cycle performance for the house. Don't
>> worry about transport distances - they're such a distant second as to
>> be a total red-herring.
>>
>> Hope this helps.
>>
>> Andrew
>>
>> 2009/2/19 Graeme North <graeme at ecodesign.co.nz>:
>>>
>>> Graeme
>>> Graeme North Architects
>>> 49 Matthew Road
>>> RD1
>>> Warkworth
>>> tel/fax +64 (0)9 4259305
>>>
>>> graeme at ecodesign.co.nz
>>> www.ecodesign.co.nz
>>>
>>> Begin forwarded message:
>>>
>>> From: Tim Owen-Kennedy <timok33 at gmail.com>
>>> Date: 19 February 2009 12:12:08 PM
>>> To: "(private, with public archives) Global Straw Building Network"
>>> <GSBN at greenbuilder.com>
>>> Subject: Re: [GSBN] Embodied energy comparisons: SB vs Stick-built
>>> Reply-To: "(private, with public archives) Global Straw Building
>>> Network"
>>> <GSBN at greenbuilder.com>
>>> Hi All,
>>>
>>> I might be wrong but I'm reading the flurry of communication
>>> lately as a bit
>>> of a sign that we are all a bit slowed down work wise; economy or
>>> winter
>>> (for us northies) or both? but I must say I'm appreciating the
>>> quality.
>>> Anyway...
>>>
>>> I'm always a fan of the "it depends" answer and the recognition of
>>> the
>>> "flaws" in the questions (I've been averaging all the lengths of
>>> the string
>>> in the craft room and will have an answer for you by next
>>> lifetime), but as
>>> hard as it is to put out numbers that can be taken out of context
>>> later it
>>> seems like it would be nice to have data on the economic impacts,
>>> embodied
>>> energy, sequestered carbon and comparative thermal performance of
>>> four
>>> simple wall assemblies, maybe 12 ft long with the same 3ft x4ft
>>> window in
>>> each. (Boy I sure love single sentence paragraphs, hope you all
>>> could
>>> follow the above).
>>>
>>> For us in California I would like to know: standard 2x6 title 24
>>> (minimum
>>> energy performance compliant) wall, high performance 2x6 wall with
>>> best
>>> accepted thermal detailing, load bearing straw bale with floating
>>> window
>>> buck, and a post and beam straw bale with the window mounted to
>>> full height
>>> 2x framing.
>>>
>>> As I write this I'm swimming in the feeling of the futility of
>>> this exercise
>>> but my assumption is that we'll see that the conventional wall has
>>> far less
>>> economic (distilled net energy from previous and potentially
>>> ecologically
>>> disastrous efforts) and embodied energy. The added costs of the
>>> roof and
>>> foundation for the thickness of the bale wall and the extra cost in
>>> detailing the bale wall will be really significant economic and
>>> embodied
>>> energy "costs". And that it might not payback easily in the thermal
>>> performance unless the project is designed to last much longer
>>> than it's
>>> mortgage, factoring in the carbon sequestration could really tip the
>>> argument. My thinking would be to get numbers attached to the
>>> value of
>>> durable natural energy efficient design.
>>>
>>> Therefore Durability has always been high on my top ten list of
>>> ecological
>>> design priorities which go something like:
>>> 1. Build as small as you can for the activities you want to house.
>>> 2. Invest the savings from building smaller in quality and
>>> durability.
>>> 3. Make all of it as personally beautiful, inspiring, and soothing
>>> to live
>>> in as your understanding allows; so that the building will be
>>> loved and
>>> cared for as it evolves.
>>> 4. Use materials that are as close to how they occur in nature as
>>> can make
>>> them durably beautiful.
>>> 5. Organize the materials to serve the activities and health of the
>>> occupants as passively as possible.
>>> 6. Adjust materials use in proportion to their availability in
>>> your area.
>>> 7. Maximize the value to the occupants of materials that are
>>> scarce and/or
>>> require lots of manufacturing or transportation.
>>> 8. Design and build with the evolution, recycling, and
>>> decomposition of the
>>> building in mind.
>>> 9. Review the Design so that the costs/impacts can be recuperated
>>> and
>>> ideally overcome by the benefits.
>>> 10. Maximize the Labor vs. materials ratio in the project -
>>> investing the
>>> most in local economies (high economic multiplier) and minimizes
>>> the risks
>>> of unintended consequences in the manufacturing, and make good use
>>> of the
>>> most enjoyably renewable resource on the planet, people.
>>>
>>> This is my attempt to frame the statements non technically toward
>>> what to do
>>> instead of what not to do; and to hopefully guide us to doing the
>>> best we
>>> can with what we know now. (My greatest design question still is
>>> since the
>>> bulk of the negative impacts of our efforts seem to come from
>>> unintended
>>> consequences - How do we design for what we don't yet know -
>>> biomimicry has
>>> been the best answer that's come so far).
>>>
>>> But it sure would be great to be able to quantify some of these
>>> concepts and
>>> adjust the priorities accordingly. It's just not something I'm
>>> capable of or
>>> I probably would have tried it by now. I would love to have any
>>> input on
>>> these that you are willing to share. Especially with regards to
>>> how best to
>>> factor in the Carbon
>>>
>>> I think the Skilled John's list is great and I would group all of
>>> them in
>>> under different priorities above. The issue always seems to me to
>>> be once
>>> you've answered each question as to what degree (relative to what
>>> standard)
>>> it is more yes or no, how do you compare it's relative value to
>>> the other
>>> answers.
>>>
>>> I love Derek's question of highest value and I've tried to address
>>> that with
>>> items 1,2,3,7 & 9 but think it could be worked in more explicitly.
>>>
>>> Well, sorry so long. I hope this is as valuable for some of you as
>>> it is for
>>> me, thanks for all your input on the refinement of "what we know
>>> now."
>>>
>>> Tim "caring and trying" O-K
>>>
>>> On Tue, Feb 17, 2009 at 8:26 AM, Joyce Coppinger
>>> <jc10508 at alltel.net> wrote:
>>>>
>>>> Count me as in favor of adding Andrew.
>>>>
>>>> Joyce
>>>>
>>>>
>>>> on 2/16/09 4:00 PM, David Eisenberg at strawnet at aol.com wrote:
>>>>
>>>> Good idea!
>>>>
>>>> David
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Graeme North <graeme at ecodesign.co.nz>
>>>> To: (private, with public archives) Global Straw Building Network
>>>> <GSBN at greenbuilder.com>
>>>> Cc: Andrew Alcorn <jandrew.alcorn at gmail.com>
>>>> Sent: Mon, 16 Feb 2009 2:53 pm
>>>> Subject: Re: [GSBN] Embodied energy comparisons: SB vs Stick-built
>>>>
>>>> Dear all
>>>>
>>>> I suggest that Andrew Alcorn be added to this list - he has been
>>>> involved
>>>> in earth and strawbale building research and design for many
>>>> years and is
>>>> one of the few researchers I know of who is delving deeply into
>>>> this
>>>> embodied and related energy stuff in buildings
>>>>
>>>> In addition it will save me forwarding on loads of emails to him,
>>>> and his
>>>> replies to you
>>>>
>>>>
>>>> cheers
>>>>
>>>>
>>>>
>>>> Graeme
>>>> Graeme North Architects
>>>> 49 Matthew Road
>>>> RD1
>>>> Warkworth
>>>> tel/fax +64 (0)9 4259305
>>>>
>>>> graeme at ecodesign.co.nz
>>>> www.ecodesign.co.nz <http://www.ecodesign.co.nz>
>>>>
>>>>
>>>>
>>>> On 17/02/2009, at 8:39 AM, Derek Roff wrote:
>>>>
>>>> How about a more abstract one:
>>>>
>>>> Is this the best use of this material?
>>>> Are we diverting/consuming a material from some other more
>>>> important use?
>>>>
>>>> This is sort of the flip side of recycling- removing things from
>>>> the
>>>> market that have other uses. The poster child for this kind of
>>>> dilemma is
>>>> crude oil. Oil pundits like to say it has a million different
>>>> uses, from
>>>> pharmaceuticals to fertilizers to building materials. Instead,
>>>> we burn 99%
>>>> of it, getting the lowest possible use from an amazing material.
>>>>
>>>> Right now, I look on ethanol this way. To produce a marginal
>>>> (perhaps
>>>> negative) energy source, we have impacted food supply and general
>>>> wealth and
>>>> health in Mexico among other places.
>>>>
>>>> I don't have an example in mind for this kind of misuse of a
>>>> material as
>>>> it relates to the building industry. Perhaps others can suggest
>>>> one.
>>>>
>>>> Derelict
>>>>
>>>>
>>>> --On Monday, February 16, 2009 11:01 AM -0800 John Swearingen
>>>> <jswearingen at skillful-means.com> wrote:
>>>>
>>>>
>>>>
>>>> Ok, since we've decided that embodied energy is of less or equal
>>>> significance as life-cycle energy use, I would suggest that any
>>>> materials or forms of construction be evaluated on at least these
>>>> areas:
>>>>
>>>>
>>>> ? Does the material contribute structurally
>>>> ? Does the material contribute thermally (insulation)
>>>> ? Does the material provide thermal storage (mass)
>>>> ? Does the material provide fire safety
>>>> ? Does the material contribute to the local economy
>>>> ? What are the manufacturing environmental costs
>>>> ? What are the transportation and wastage environmental costs
>>>> ? Is the material a by-product, waste-product, or recycled
>>>> ? Is the material bio-degradable, recyclable or land-fill
>>>> ? Is the material toxic in manufacture, use or disposal
>>>> ? What is the expected life-span of the system (resistance to
>>>> environmental damage)
>>>> Feel free to add.
>>>>
>>>> John
>>>>
>>>>
>>>>
>>>>
>>>> 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
>>>>
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