[Strawbale] bogus comparisons was: Anti Cement Folks

[John Swearingen]

On 5/9/07, Stone Tool <owly at ttc-cmc.net > wrote:
>
>
> Here's why:
>
> Cement and Lime are both lime based products, and the lime must be
> calcined which releases CO2 into the atmosphere as the lime is converted
> from calcium carbonate to calcium hydroxide.    In this case lime
> produces more because cement is composed of only 75% lime


I could be wrong, but I believe you've got it backwards.  Lime sequesters
CO2 when it sets, though not enough to make much difference. It is cooked at
a lower temperature, and so, overall would have a lower embodied energy.


> This means that cement does not require much shipping, and in many cases
> lime must be shipped many hundreds of miles to get to your building
> site.....Do you give a damn about the truth?


Let's take a little time to discover the truth, shall we.  You have an
interesting theory, about transportation costs and on the surface it appears
self-evident. Embodied energy analysis is tricky, though. The devil is in
the details.  Let's look a little deeper, in pursuit, as you suggest, of the
truth.

First, there are 115 cement plants in the US, in 38 states. To me, that
means that there is still plenty of room for trucking, even thought the
plants are strategicly located to reduce transport costs.

According to the Portland Cement Association, then, a goodly amount of your
"local" cement might have come from thousands of miles away:

"The gap between domestic production and consumption was filled in 2002 by
24.2 million metric tons of imported cement and cement clinker. About 56% of
cement and clinker imported in 2002 came from four major countries: Canada,
Thailand, China, and Greece. Imports from Thailand, less than one million
metric tons in 1998, surged to 4.3 million metric tons in 2002.

"Cement and clinker importation is generally cyclical. Typically smaller
amounts of cement are imported during recessions — perhaps less that 5% of
total national consumption — but during boom times, imports can increase to
20% or more of total national consumption."

So, that cement truck hauling down the highway with the American flag on the
side might be smokin' some of that famous 'Thai clinker".  Oh, and another
interesting tidbit: "Foreign companies now own approximately 81% of U.S.
cement capacity, up from about 22% in 1980."

> Let's remember that so called "embodied energy" is a huge
>
part of the cost of most products we buy.  If it takes more energy to
> produce and deliver, it will cost more........ that's pretty
> simple......


Ah, no sooo simple. The whole smoke and mirrors of the problem is that  the
embodied energy in a material, or more specifically the environmental cost,
is not usually reflected in the relative purchase price of that item.  Just
a few examples, you can find many more in your local Costco, Wallmart or
Home Depot, where price rules over all other considerations:


   - Aluminum windows have a very high embodied energy,and vinyl windows
   have a high environmental cost, but they are cheap relative to wood windows.
   - Tobacco is cheap, but cigarettes have been determined to carry with
   them a high cost to the government in health care: sickness, lost work and
   death.
   - Death from smoking might be cheaper than a long life with emphysema
   (a cost of asbestos), but it's not a desirable social cost.
   - Synthetics and high-tech products generally have high embodied
   energy and environmental costs, but low labor costs, and so are cheaper to
   buy (cotton vs. polyester).
   - Imported goods (you name 'em, we've got 'em) also reflect lower
   labor costs which greatly offset the higher transport costsm  etc. etc.
   etc....



>         Shut off  you AC and your lights and refrigerator.....


Excellent idea!  Generation of electricity and fuels used for heating and
cooling are a major of greenhouse gases   Make your home energy efficient.

A recent NPR show on questions about global warming  (
http://mail.google.com/mail/?account_id=john.skillfulmeans%40gmail.com) puts
things into perspective :

An average car in the United States emits about 4.5 tons of CO2 equivalence
into the atmosphere per year. A power plant, by contrast is 8.3 million tons
for a coal-fired power plant. And you think about the difference in the
scale – you may be driving your car significantly, but the kind of power
that you're choosing to purchase actually has a bigger impact over the
lifetime of those emissions. A difference between a hybrid and an SUV,
however, is quite significant.

*Harris: *And the power plants are about 40 percent of our greenhouse-gas
emissions.

*Siegel: *Well, then that's still only accounting for about 60 percent of
all the greenhouse emissions. Where is the rest coming from?

*Harris: *Industrial uses are a big part of it. And a lot of heating – for
example, buildings are a huge consumer of energy.

*Layke: *Globally, another source of emissions is actually land use change.
And that is the difference between where the United States is in its
development pattern and other countries like Brazil or Indonesia that have
very serious conversion going on from forests to agriculture in order to
help development cycles.

John "Disembodied Energy"  Swearingen


John Swearingen
Skillful Means, Inc.
Design and Construction
www.skillful-means.com