PV Degradation Rate
PV Degradation Rate
(OP)
The degradation rate of PV current production is yidely reported with values between 0.5% and 1%/year.
From example calculations I have seen this rate appears to be used as a constant, but I don't understand how it could possibly be a constant. Certainly, with a degradation rate of 0.5%, the average power output in any given year must be = Wo * (1-.005)^(year-1). Are the examples I have seen in error?
From example calculations I have seen this rate appears to be used as a constant, but I don't understand how it could possibly be a constant. Certainly, with a degradation rate of 0.5%, the average power output in any given year must be = Wo * (1-.005)^(year-1). Are the examples I have seen in error?
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RE: PV Degradation Rate
I have seen numbers like 80% output after 20 years,
Cheers
Greg Locock
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RE: PV Degradation Rate
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RE: PV Degradation Rate
Green, MA. Silicon solar cells: advanced principles and practice. Sydney, Bridge Printery, 1995.
I think it will have some discussion of degradation. You could write to Martin at UNSW, he is a very helpful guy.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: PV Degradation Rate
http://www.nrel.gov/docs/fy02osti/31455.pdf
CONCLUSIONS
Analysis of data from a long-term solar weathering
study of commercial crystalline Si modules has revealed a
slow Isc degradation, which began after the rapid initial lightinduced
degradation caused by oxygen contamination in
boron-doped Si solar cells. The rate of the slow degradation
may be intrinsic to individual solar cell manufacturing
processes. Because of a linear correlation between the
slow degradation and the UV exposure dose, and because
the same rates were observed under UVA-340 fluorescent
illumination, the degradation is probably caused by UV absorption
at or close to the top Si surface. Quantum efficiency
measurements indicate that the bulk of the Isc losses
(both rapid and slow) occurred in the response region above
700 nm. Considering previous literature reports of Isc losses
with our results, it is very unlikely that the slow degradation
was caused by encapsulation browning. The degradation
also does not seem to be thermally activated.
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"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain