RE: Solar Panels

["Heinmiller, Bruce" <heinmillerb@aecl.ca>]

I'd be interested in the number as well.  I have an unofficial energy
manufacturing cost of 1360 kWh/m^2 of photovoltaic panels.  Assuming a very
generous installed electricity production rate of 0.4 kWh/d.m^2, the energy
payback time would be almost 10 years.

But I'm skeptical about my 0.4 kWh/d.m^2.  I was at Mountain Equipment Co-op
in Toronto a couple years ago near noon on a largely cloudless day in June.
This store touts there "1-kW" roof-mounted solar panel unit (with a power
meter at street-level) as a model of environmental stewardship.  When I was
there, the display was, for some reason, cycling from zero W to about 250 W
(plus or minus 30 W) when the sky was cloudless.  When a puff of cumulous
cloud intervened for a minute, the display read "sleeping", which I
interpreted quantitatively as zero W.  The following year (last year) I
happened to be there again on a cloudless day in June (my records indicate
Sunday, June 6, 12:00), and the unit was behaving more consistently - it
continuously read "sleeping" on that beautiful day about two weeks shy of
summer solstice.

I wouldn't need a lot of convincing that these trinkets are a net energy
drain.  Furthermore, I'd like to see a comprehensive safety analysis report
for this technology, including waste management, construction, and
maintenance risks (even per unit gross energy produced).

Bruce Heinmiller
heinmillerb@aecl.ca

> ----------
> From: 	Ted de Castro[SMTP:tdc@xrayted.com]
> Reply To: 	radsafe@romulus.ehs.uiuc.edu
> Sent: 	Tuesday, May 02, 2000 2:16 PM
> To: 	Multiple recipients of list
> Subject: 	Solar Panels
> 
> While on the subject of Solar Panels - or Photo Voltaics (PVs) I'd like
> to see if anyone has hard information to settle a long standing
> question.
> 
> Of course we all know that the Si industry has somehow avoided general
> knowledge of the extremely corrosive and hazardous chemicals they use. 
> That has already been mentioned here.
> 
> BUT - I once read that it takes more energy to produce a PV than it will
> EVER produce!
> 
> Does anyone have the hard numbers on this?
> 
> Currently I am persuaded this may be so.  10 or so years a ago I did a
> simple calculation at the surplus price of solar panels and the time to
> payback from the electricity they generated.  The idea was that if
> energy cost was a major part of the cost of producing a solar cell then
> the time to cost recover from electrical generation alone would be very
> long.  This was NOT meant to be a definitive calculation - but just one
> for plausibility - certainly other factors can raise the cost. 
> Conversely if the payback time was short - then obviously they could NOT
> consume more energy than they could produce.
> 
> The payback time calculated to about 60 years.  Thus I concluded that it
> certainly is possible that they COULD require more energy to produce
> than they could ever put out.
> 
> More recently I had a project for a remotely cited monitoring station
> where a PV was THE answer for power!  It is a temporary project and the
> cost to get power to the site was high.
> 
> BUT - to design the project to be SURE the PV and batteries where right
> to carry the load year round I had to do some calculations.  So - I did
> a spreadsheet using actual hourly solar data for our site from the
> previous year and calculated the charge state of the batteries hour by
> hour.  This allowed me to choose between panel and battery capacity and
> minimize cost.
> 
> The panel we use is a $615 120w crystalline panel.  An amorphous panel
> would have been about the same price but 50% larger.
> 
> This panel was bought from Wind and Sun in Arizona - I found their web
> site and excellent source of information (www.windsun.com).
> 
> They made the observation that PVs really haven't come down much in 20
> years - and as for the future ....Their opinion is to "not to hold your
> breath".  Pretty frank talk for someone making a living selling this
> stuff!!  They also say that PVs NOW do produce more than it takes to
> make them (but no hard data).
> 
> Anyhow - seeing this thread on alternative power sources I realized that
> my spreadsheet designed to calculate battery charge could also calculate
> total power output and I could redo the time to payback calculations I'd
> scratched out before AND with current industry pricing for the largest
> single PVs I could find.
> 
> Guess what - once again the answer was 60 years!!!
> 
> The guarenteed life of a PV to 80% capacity is 5 to 10 years depending
> on the make and type (amorphous has a shorter life).
> 
> So - it is still plausible in my mind that the power to produce a PV
> could very well exceed its life time generating capacity - or be very
> close to it.
> 
> The argument is often made that PVs are too costly now for "normal"
> installations - but as power costs go up - this will change.  BUT it is
> obvious that if power is a major cost to make PVs - then their price
> will go up accordingly.
> 
> Of course we could always wish for a new break through process that
> makes them better and cheaper and more efficient.  But that is NOT here
> and now - or even in the visible future AND has been "promised" for
> almost as long as nuclear power has been said to become "too cheap to
> meter".
> 
> Ted de Castro
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