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Darryl, <br><br>
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?<br><br>
Drake <br><br>
<br><br>
At 06:16 PM 4/8/2010, you wrote:<br>
<blockquote type=cite class=cite cite="">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.<br>
<br>
I have heard there are some very good studies with similar results.<br>
<br>
Thank you--Darryl<br><br>
--- On <b>Fri, 4/9/10, Drake Chamberlin
<i><drake.chamberlin@redwoodalliance.org></i></b> wrote:<br>
<dl><br>
<dd>From: Drake Chamberlin
<drake.chamberlin@redwoodalliance.org><br>
<dd>Subject: Re: [RE-wrenches] Voltage degradation<br>
<dd>To: "RE-wrenches"
<re-wrenches@lists.re-wrenches.org><br>
<dd>Date: Friday, April 9, 2010, 12:24 AM<br><br>
<dd>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.<br><br>
<dd>Thanks,<br><br>
<dd>Drake <br><br>
<dd>At 11:08 AM 4/8/2010, you wrote:<br>
<blockquote type=cite class=cite cite="">
<dd>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.<br>
<dd> <br>
<dd>Nick Soleil<br>
<dd>Project Manager<br>
<dd>Advanced Alternative Energy Solutions, LLC<br>
<dd>PO Box 657<br>
<dd>Petaluma, CA 94953<br>
<dd>Cell: 707-321-2937<br>
<dd>Office: 707-789-9537<br>
<dd>Fax: 707-769-9037<br><br>
<br><br>
<dd><font face="Tahoma" size=2>From:</b> Drake Chamberlin
<drake.chamberlin@redwoodalliance.org><br>
<dd>To:</b> re-wrenches@lists.re-wrenches.org<br>
<dd>Sent:</b> Tue, April 6, 2010 1:58:56 AM<br>
<dd>Subject:</b> [RE-wrenches] Voltage degradation<br>
</font><br>
<dd>Esteemed Wrenches, <br><br>
<dd>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.<br><br>
<dd>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. <br><br>
<dd>Thanks,<br><br>
<dd><font color="#0000FF">Drake Chamberlin<br>
<dd>Athens Electric<br>
<dd>OH License 44810<br>
<dd>CO License 3773<br>
<dd>NABCEP </font><font size=1 color="#0000FF">TM
</font><font color="#0000FF">Certified PV Installer <br>
<dd>Office - 740-448-7328<br>
<dd>Mobile - 740-856-9648 <br>
</font><br>
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<dd><font color="#0000FF">Drake Chamberlin<br>
<dd>Athens Electric<br>
<dd>OH License 44810<br>
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<dd>NABCEP </font><font size=1 color="#0000FF">TM
</font><font color="#0000FF">Certified PV Installer <br>
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<font color="#0000FF">Drake Chamberlin<br>
Athens Electric<br>
OH License 44810<br>
CO License 3773<br>
NABCEP </font><font size=1 color="#0000FF">TM
</font><font color="#0000FF">Certified PV Installer <br>
Office - 740-448-7328<br>
Mobile - 740-856-9648 </font></body>
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