[RE-wrenches] Volcanos and reduced solar production

SOLARPRO at aol.com SOLARPRO at aol.com
Sun Apr 25 12:13:49 PDT 2010


Joel:
 
I have noticed that the energy predicted by the CSI calculator  is 
consistently lower than the first year output of our systems, usually by at  least 
10% to 20%. This is also true of the PVWatts version we use.
At first we thought that we had done such a great job!   But I believe that 
the accumulative conservative default values in both  calculators and the 
expectation for module degradation built in to the source  code is the real 
answer.  If our customers ever have an issue with  understanding lower 
production, it is usually because they fail  to recognize that daily or monthly 
production values relate to annual  production expectations on a non-linear 
basis.  Recently El Nino has  dramatically affected generation and as well, 
our own production  schedule.
Kicked out butts, in fact.
 
Pat Redgate
Ameco Solar
 
 
 
In a message dated 4/25/2010 9:43:09 A.M. Pacific Daylight  Time, 
joel.davidson at sbcglobal.net writes:
 
Wrenches,

With the Iceland volcano in the news and winter  over, I thought it would 
be 
a good time ask wrenches convince their  customers that their reduced solar 
production was caused by atmospheric  conditions and not their PV system. 
I'm 
not talking about short-term  conditions like a few cloudy days. I mean 
when 
you install a PV system in  October and have to explain in gloomy February 
why their PV system is not  performing like you predicted.

Missing the mark can be bad for  business. For example, reduced insolation 
caused by the El Chichon Mexico  volcano was reportedly one of the reasons 
that the Luz solar power plants  went bankrupt in the 1980s. See  
http://en.wikipedia.org/wiki/Solar_Energy_Generating_Systems and  
http://www.unige.ch/cuepe/html/biblio/pdf/michalsky-ineichen%201993%20-%20mo
unt%20pinatubo%20and%20solar%20power%20plants%20(solar%20today).pdf

Joel  Davidson 

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