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<DIV><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Jason:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Be careful of drawing false comparisons. There is no free lunch.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Beyond the energy yield issues there are some reliability issues.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>You should also consider that running an inverter flat out all the time will shorten it’s life (due to the Arrhenius effect). <a href="http://en.wikipedia.org/wiki/Arrhenius_equation">http://en.wikipedia.org/wiki/Arrhenius_equation</a><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Think of the inverter temperature in the same way you would the power output curve (the two are closely related). Moving the whole power curve up “more on the shoulders” also moves the whole temperature curve up as well.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The average lifetime (all this stuff is only probabilities) was projected with certain assumptions about how many hours at what temperature. As module sizes increase a given inverter will spend more time at a higher power level, i.e. runs hotter longer, which non-linearly reduces the life of the product.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Just my $0.02… With the high labor cost of replacement it might be better to undersize the module relative to the power electronics or vice versa. This may or may not increase the installed system cost depending on the products you choose. Running everything flat out all the time is probably not the greatest idea. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Best Regards,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>John Berdner<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>General Manager, North America<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><img alt=SmallBannerPictEngnew border=0 height=113 id="Picture_x0020_1" src="cid:image001.jpg@01CDFD3C.B73855C0" width=468><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>SolarEdge Technologies, Inc.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>3347 Gateway Boulevard, Fremont CA 94538 USA </span><b><i><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#C00000'>(*Please note of our new address.)</span></i></b><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><br>T: 510.498.3200, X 747<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>M: 530.277.4894 <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Jason Szumlanski<br><b>Sent:</b> Monday, January 28, 2013 5:30 AM<br><b>To:</b> RE-wrenches<br><b>Subject:</b> Re: [RE-wrenches] high insolation value and inverter undersizing<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal style='margin-bottom:12.0pt'>I found the latest module "rightsizing" paper by Enphase pretty interesting. It does stand to reason that there are a lot of hours in the day where the inverter is producing less than rated power, so increasing the module size makes sense. Obviously there is an optimum point in every system where clipping exceeds gains, but that's virtually impossible to nail down due to so many factors being involved. I think the point would be that PV mods are coming down in price so much that "rightsizing" is basically equivalent to "upsizing," within reason, of course. Spending an extra 25% on PV might increase the installed system cost by 5-10%.<o:p></o:p></p><div id="WISESTAMP_SIG_gmail_session"><div><div style='margin-bottom:6.0pt'><p style='margin:0in;margin-bottom:.0001pt'><strong><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:gray'>Jason Szumlanski</span></strong><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p></o:p></span></p><p style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:0in'><em><span style='font-size:10.0pt;font-family:"Verdana","sans-serif";color:gray'>Fafco Solar</span></em><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'><o:p></o:p></span></p></div></div></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p><div><p class=MsoNormal>On Sun, Jan 27, 2013 at 6:00 PM, Marco Mangelsdorf <<a href="mailto:marco@pvthawaii.com" target="_blank">marco@pvthawaii.com</a>> wrote:<o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>I have had a concern for a long time that as PV modules have gone up in output that there is inevitably going to be more and more clipping taking place as they’re paired with comparatively lower output inverters. In effect, matching, say. a 260-watt module with a micro inverter with a max output of 225 watts reduces that 260-watt mod to 225 watts. It’s not a matter of if clipping will take place, but how much and how much actual harvestable energy will be lost.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Out here in the tropics, even in January with the lower sun angle, we see irradiance levels well above 1,000 watts/square meter range. Take a look at what I copied today from a weather station that we installed at nearby installation.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Given the clipping issue inherent in using undersized inverters, it seems to me that moving to larger output micros makes a whole lotta sense. I’ve got one of the first installs using the Power-One 250-watt and 300-watt micros and am so far quite impressed. Why use a 225-watt rated micro with a 225-watt or higher output mod when larger micros are now readily available?<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>What are the views out there regarding this clipping issue? Is it as minimal as our Enphase friends suggest in their latest white paper or more of an issue as I conclude?<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>marco<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white'>Environmentals from Weather Station at a Hilo, Hawaii installation<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white'><b> </b><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white'>Sunday, January 27th 2013, 12:40:00 pm<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white;vertical-align:middle'><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white;vertical-align:middle'><b>Ambient Temp.</b> 25.30 °C<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white;vertical-align:middle'><b>Cell Temp.</b> 41.70 °C<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white;vertical-align:middle'><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white;vertical-align:middle'><b>Insolation</b> 127.81 kWh/m²<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;background:white;vertical-align:middle'><b><span style='font-size:16.0pt'>Irradiance <i>1,175.00</i> W/m²</span></b><o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div></div></div></div></div></div></DIV>
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