Relative importance of embodied energy?
I read this case study by David Fridley of Lawrence Berkeley National Laboratory:
http://www.theoildrum.com/node/6842
Then I remembered one of Martin’s blog entries:
https://www.greenbuildingadvisor.com/blogs/dept/musings/energy-use-most-important-aspect-green-building
The case study indicates that when evaluated on a annual basis, the embodied energy of a residential building is roughly equal to the energy consumed for its operation. The case study assumes a 30 year life-span for these buildings which is average in China.
Many of the comments made in Martin’s blog suggest a view that operational energy consumption over the life of the building is a more critical consideration.
Questions:
1. If embodied energy is roughly equivalent or even somewhat less than total life-cycle operational energy consumption, shouldn’t material selection, building practices and location receive just as much attention as designing for efficiency?
2. Is there any standard approach for including embodied energy into a net energy use model?
Interestingly, the results of this case study suggest that embodied energy forms a much larger piece of the energy use pie than operational energy consumption when taking a wider view of urban living. Particularly interesting is the ratio of embodied energy tied to human consumption to the embodied energy tied to residential buildings… Food for thought for those who don’t believe that humans are the elephant in the room.
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Replies
Lucas,
This report serves to quantify one of the most significant qualitative impacts that humanity imposes on the biosphere: that large concentrations of human biomass are a cancer on the earth. While I disagree with much of Derek Jensen's philosophy (author of Endgame and Resistance Against Empire), I appreciate his definition of a city: a large-scale concentrated human habitation that exceeds the carrying capacity of its local environment and hence requires the exploitation of resources from somewhere else. Cities, in other words, are unsustainable by definition.
It's hardly worth arguing whether the embodied energy or the operational energy of a single-family home is more or less important. Either type of consumption, if it derives from fossil fuels, is terribly problematic and unsustainable - both economically and ecologically. And we never factor in the embodied and operational energies of the suburban and rural infrastructure required to supply those single-family homes. This LBNL study suggests that this infrastructure is enormous and highly impactful.
What should be obvious is that both cities and single-family suburban homes are obsolete and unsustainable. We will not survive as a species unless we learn - and very quickly - to differentiate between needs and wants, do more with less, and share essential resources in extended family, multi-generational compounds and village-based communities.
We really shouldn't need scientific studies to "prove" what common sense makes clear and ecological ethics requires.
I think an emphasis on reducing operational energy is pragmatic in the short term. Its the low hanging fruit which the majority of build projects aren't accounting for and this is irresponsible. But material choice impacts are as important (E=MC2).
Some think Life Cycle Assessments (which encompass embodied energy among many other categories) will be the authoritative tool for sustainability. At one point I tried to familiarize myself with several LCA software developments but found LCA measurements too subjective in their distillation of many complex issues into numerical scale. Also I'm afraid that LCA rankings are prone to lobbying efforts. (The vinyl and portland cement institutes have funded LCA software development).
I subscribe to Buddhism. The teachings of Buddhism point out that reality is an ever changing set of circumstances following the logic of karma (except for one thing that does not change.)
I think the concept of karma is important for the building trades as well. We could talk of the karma of a material or the karma of a particular source of energy. This wood I sourced where did it come from? How was it manufactured and what kind of world does this manufacturer create? Are all the impacts of using this wood (or any another building material or energy source) help create a more compassionate world for all living beings?
Agreed. It should not be either/or but should be both... and then some. Once a realistic net energy use picture is painted for the building taking into account embodied energy, add the component of energy use (embodied and operational) that constitutes that portion of the web of infrastructure that supports that building. Though an amazingly complex calculation, an energy use model like this could provide a much more realistic idea of the actual energy footprint of a building. I suspect that the results generated by such a model could be quite discouraging to many as it would probably become a little too apparent just how far out in left field we are. The impossibility of the suburb of "green" net-zero mcmansions springs to mind.
Agreed. However it seems that common sense is in short supply in the world today. What other tools are available to illustrate and understand the magnitude of our energy use?
So, is there movement towards understanding sustainable building from this broader view or am I right in thinking that we're not there yet?
I'm not sure that I agree that "We really shouldn't need scientific studies to 'prove' what common sense makes clear and ecological ethics requires."
When it comes to the average person's understanding of these issues -- embodied energy versus operational energy -- common sense is of little use. If you ask 100 people some basic energy use questions, or questions concerning the cost effectiveness of retrofit measures, the "common sense" answers you get will almost all be wrong.
I'm not just guessing; pollsters have conducted such surveys and verified what I just wrote. The average American's common-sense understanding of energy issues is worse than useless.
Assembling data and analyzing the data are far more useful approaches to these issues than following common sense.
" If embodied energy is roughly equivalent or even somewhat less than total life-cycle operational energy consumption, shouldn't material selection, building practices and location receive just as much attention as designing for efficiency?"
my understanding is the operational energy of most houses is 10-12x or more greater than the embodied energy. this jives w/ research from passivhaus institut as well.
http://www.passivhaustagung.de/Passivhaus_D/Primary_Energy_Input_comm2007.pdf
it's only when you get operational energy down significantly (e.g. minergie, passivhaus, net zero), that the embodied energy issue really gains any weight.
Not true.
Depending on whose figures you use, a "typical" house has the embodied energy equivalent of 15 years of operating energy and, depending on the relative efficiency of the house, it can take between 10 and 20 years for OE to overtake EE (http://www.yourhome.gov.au/technical/images/52a.jpg).
In another study, it takes 10 years for OE to overtake EE in a "normal" house and 30 years in an efficient house, but while the EE of the normal house comprises 20% of its (50 year) lifetime use it comprises 40% of the efficient home's total usage (http://www.structuremag.org/images/0609-ed-2.gif).
And, once again, this ignores the EE and OE of all the infrastructure necessary to support that single-family home.
According to that first graph, the lifetime OE is about double the EE for a 50-year lifespan and only 3-4x for a 100-year lifecycle.
The average person's ability to absorb and comprehend and draw accurate conclusions from data and charts and graphs is inadequate. But a simple person can understand that an energy orgy can't go on forever and that once the pantry's empty the party's over.
"Waste not want not", "A penny saved is a penny earned", "Use it up, wear it out, made do or do without". These were not scientific discoveries, but the most elemental and universal common sense. j
Only for geeks. It may be true that most middle class Americans are sleepwalking in a Madison Avenue dreamland (or were until the economy collapsed), but the simple folk and the poor and most third world people do have enough common sense to understand that the way we Westerners live is not only unsustainable but inequitable and immoral.
Remember, there are three kinds of lies: lies, damned lies and statistics. Numbers are used as often to deceive as to enlighten, and numbers aren't real - you can't eat them or plant them or build a house with them. But they're great for getting grant money and for publishing in peer-reviewed journals.
Lucas,
You ask, "So, is there movement towards understanding sustainable building from this broader view or am I right in thinking that we're not there yet?"
Yes and yes.
One of the best "measurement" tools for understanding the full impact of our consumer choices and lifestyles (including housing choices) is the Ecological Footprint, which approximates the acreage of Earth required to supply our material needs/wants and to absorb our wastes. We Americans are consuming at least 2½ times our fair share (and that's if we divide the earth only among people and leave nothing for the other species), and the global population surpassed the carrying capacity of Earth sometime between 1970 and 1980. In other words, our lifestyles are diminishing the carrying capacity of Earth at the same time that we continue to generate more human biomass and more human "wealth".
http://www.footprintnetwork.org/
http://www.myfootprint.org/
Are we there yet? Not even close. Not in American society in general or even in the "green" building movement. We continue to demand more than is rightfully ours, more than the Earth can tolerate, and rob our children and grandchildren's future while dragging millions of innocent species down with us.
But the "good" news is that we're not going to be able to continue along this suicidal path for much longer. The US economy is well on its way to total collapse, and the rest of the "developed" world is close behind.
http://thetruthwins.com/archives/40-bizarre-statistics-that-reveal-the-horrifying-truth-about-the-collapse-of-the-u-s-economy
The payback period ($ cost, or energy) depends on the climate and building operation. In Australia, historically glasswool and polyester wool easily met Total R requirements of buildings, but the government has mandated much higher R values now, and there are many instances where only exotic insulations with low conductivity can fit available insulation space. But these usually have a much higher embodied energy per unit R value, so take longer for payback. In fact, I believe there are many instances where the additional embodied energy of the exotic insulation may never be recovered in the life of the building. Further info may be posted at http://fricker.net.au
In particular, the optimum insulation for milder climates is considerably less than for cold climates, so regulators should be careful not to insist on excessive R requirements.