Thanks for the myth-busting!
Funny how life cycle analysis is so often applied to renewables, yet
so rarely applies to fossil fuels; I'd like to see more extraction to
emissions analysis of fracked gas, coal (especially via mountaintop
removal; cooling towers for any power generation by boiling water, etc.)
Margaret
On Dec 3, 2009, at 10:28 PM, Shawn Reeves wrote:
Nov 24, Eric Banford wrote:
The book I am almost done with "The Long Descent" by John Michael
Greer mentioned that some studies showed that solar panels and wind
mills took more energy to make than they produced over their life.
Maybe that was true and isn't anymore? I know advancements are
being made, hopefully a breakthrough will bring the cost of
production way down.
Sigh...Time for a reply from someone who asks the rude questions on
pv-plant tours, someone who walks around with a light meter:
ON SOLAR PV
Those little PV cells in your calculator and watch *do* take more
energy to produce than they produce in their lifetime, because they
are usually indoors.
...But...
Monocrystalline modules like Schott and Evergreen Solar now use
about 15% (best in the industry) of the energy they'll produce in
their warrantied lifetime to be manufactured, including mining,
glazing, aluminum production, etc. Unless you have neighbors who
throw rocks for sport, your modules will last much much much longer
than the warranty. After 50 years they may require re-glazing
(diddly-squat in the scheme of things). After 100 years, our
granchildren will be laughing at how their grandparents were scared
of progress, how tiny little itty bitty energy it took to make the
panels on Grandma's house. Get a tracking system and you'll
contradict Greer's citations even faster.
If you install a panel facing north, then yes, it won't produce as
much energy as it takes to make, unless it's working for about 150
years.
I have an Evergreen Solar module that is not recouping the energy it
took to manufacture, but only because it is sitting in my hallway.
(I use it for education). Its disuse, compared to its potential,
symbolizes the fact that nay-sayers are the reason solar (and other
awesome technologies) are not doing the heavy lifting yet in our
economy; speculative capitalism is always a lesson in self-
fulfilling prophecy. Decades of missed opportunities.
It's very important to consider the unbalance, though, between solar
energy availability and prices: With less sun but higher electric
rates here in CNY, Solar PV pays for itself money-wise more quickly
than in the South, but produces less energy. So, economics are
forcing us to install them not in the place where they'd do the most
work. We need a mechanism that would take Northern capital and
invest in Southern PV exposure. Hmmm, interstate commerce...Congress?
ON WIND
The idea that a properly sited modern wind turbine couldn't generate
as much energy as it takes to produce is off the mark.The cost of a
turbine installation is mostly spent on fancy labor, fancy
materials, fancy electronics, and fancy, fancy construction
equipment, not the energy bill.
This is the same silliness that people suffered when believing those
kooky myths that Prius hybrid drive systems took more energy to
produce than they'd save. As in the wind turbine case, the cost of
the drive system was less than the savings, therefore the energy
used to produce the drive system, which must have been less than
100% of the cost of the drive system (gotta leave dough to buy the
materials and labor), was less than the energy saved.
Properly sited, megawatt scale wind turbines are money machines as
much as energy machines. 150 ton money machines, they take between
one and three million dollars of labor/materials/transportation/
equipment/etc. and sixty thousand dollars worth of energy and turn
that capital into a fifth of a million dollars of energy per year.
They pay for themselves in energy in less than a year, and in money
in 5-15 years. About half of the embedded energy of a large turbine
is in the materials, half in the logistics.
--
-Shawn Reeves
not necessarily the opinion of EnergyTeachers.org
[email protected]
http://energyteachers.org
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For more information about sustainability in the Tompkins County area, please
visit: http://www.sustainabletompkins.org/
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