Darryl,
Thanks for the information. Is the 1% / year strictly voltage
degradation? If so, I think we should select our inverters to handle
20% voltage degradation since the modules have a warranty for at
least 20 years. If 50% of the degradation is current and 50%
voltage, then sizing for a 10% degradation might seem
reasonable. Will modules actually put out usable power for 40
years? Should we take the long term into account?
Drake
At 06:16 PM 4/8/2010, you wrote:
Drake, I measured and published a paper in 1992 on the after 10 year
performance of solar modules, my study concluded these modules
degraded approximately 1% per year. The purpose of the study was the
effect on utility demand.
I have heard there are some very good studies with similar results.
Thank you--Darryl
--- On Fri, 4/9/10, Drake Chamberlin
<drake.chamber...@redwoodalliance.org> wrote:
From: Drake Chamberlin <drake.chamber...@redwoodalliance.org>
Subject: Re: [RE-wrenches] Voltage degradation
To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org>
Date: Friday, April 9, 2010, 12:24 AM
What is the documentation for 10% module voltage degradation? I
have heard different ideas on what will degrade over how much
time. For direct grid tie, I shoot for a voltage drop 1% maximum on
the DC side.
Thanks,
Drake
At 11:08 AM 4/8/2010, you wrote:
I usually keep in mind that the modules will degrade by
10% However, if you are one of those wrenches promoting 3% DC
Voltage Drops, maybe you should add some more.
Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037
From: Drake Chamberlin <drake.chamber...@redwoodalliance.org>
To: re-wrenches@lists.re-wrenches.org
Sent: Tue, April 6, 2010 1:58:56 AM
Subject: [RE-wrenches] Voltage degradation
Esteemed Wrenches,
How much voltage overhead should we have available on our arrays to
allow for inverters not to fall out of their DC voltage operating
range? Since the module power degradation is 20% over the warranty
period, I usually shoot for a module voltage that can drop 20% and
still be within the MPPT range of the inverter under the average
high temperatures, since most of the degradation is in voltage.
Am I being too conservative with this number? It always pushes the
number of modules to the top of what is allowable on the string for
the extreme low.
Thanks,
Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
NABCEP TM Certified PV Installer
Office - 740-448-7328
Mobile - 740-856-9648
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OH License 44810
CO License 3773
NABCEP TM Certified PV Installer
Office - 740-448-7328
Mobile - 740-856-9648
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