Alternate Home Power In A Disaster Zone - Page 2

 

Derek Broughton wrote:

I was mostly objecting to the high cost of PV. It takes almost 20 years
of fully productive days to repay the energy it cost to manufacture the
PV panels in the first place. If you are in an emergency situation, more
gallons of diesel would be more useful, and provide power at a much
faster rate.

 

On Tue, 13 Sep 2005 08:15:55 -0600, Mike McWilliams


A deception..

http://www.ecotopia.com/apollo2/pvlever.htm

June 2000: paper... demostrates that payback for production PV modules
ranges from 2-3 years and energy output varies between 9-17 times the
input.


http://www.nrel.gov/ncpv/energy_payback.html
"What is the Energy Payback for PV?"

"Other recent calculations support Alsema's figures. Based on a solar-
grade feedstock, Japanese researchers Kato et al. calculated a
multi-crystalline payback of about 2 years (adjusted for the U.S.
solar resource). Palz and Zibetta also calculated an energy payback of
about 2 years for current multicrystalline-silicon PV."

  I.E.  2 to 3 years for a PV panel oriented at latitude using average
solar raditaion data for the lower 48(states).   PV payback time drops
by upwards of 3 fold depending on location and/or usage of tracking.

 


Tim Keating wrote:


I'm confused, if the energy payback time is so quick, why are PV panels
so expensive?  Is it due to raw materials, the sand that provides the
silcon plus some chemicals (seems unlikely)?  Is it the manpower
involved?  Is it the energy needed to purify the sand and all the
succeeding steps?  If it's energy, can't a production facility be built
in a sunny state that runs on PV cells?  They do get them at cost.
What determines the high price of PV cells?

And I don't buy that increasing-demand-will-someday-lower-costs
arguement.  Plenty of other industries start out losing money and
quickly make it up in volume.  The PV industry has had 20+ years to
break that logjam.

 

jjj_soper@hotmail.com wrote:


growing the crystals and cutting the wafers (lots of loss) is expensive.
low volume production also contributes.

--
Steve Spence
Dir., Green Trust, http://www.green-trust.org
Contributing Editor, http://www.off-grid.net
http://www.rebelwolf.com/essn.html

 


Steve Spence wrote:

OK, then why is growing the crystals and the loss from cutting wafers
expensive?
Is it the cost of raw materials, energy, or manpower?  If it's energy,
which I suspect it is, wouldn't that contradict the energy payback
figures?
Low volume production would be high volume if the price was less.