Hi Guys,
I might be able to shed some light on the Uni-Solar performance disparity bouncing back and forth here. Uni-Solar put out a low-performing (some might call them defective?) batch of US-64's back around 2004 I believe. As an employee of Uni-Solar's primary North American distributor I've seen a couple of these cases crop up. Jay, if this system was installed in the 2003-2005 time frame, and the cells have the slightly reddish outer edges, then they're suspicious. Collect serial numbers and contact Uni-Solar. The reddish edges disappeared when Uni-Solar's 2nd generation deposition machine came online in late 2004. Wattage ratings on most modules went up a little bit at this time also. Most folks experiences with Uni-Solar have been like Joel's. They perform just a little bit better than crystalline.5%-7% is typical, although it depends on temperature. Hot climates favor amorphous silicon, cold climates favor crystalline silicon. Cheers, Doug Pratt DC Power Systems From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Joel Davidson Sent: Saturday, November 01, 2008 10:00 AM To: RE-wrenches Subject: Re: [RE-wrenches] crystalline VS uni-solar and beyond Hi Jay, My experience was the exact opposite with Unisolar triple-junction structural standing seam systems in 1996 and megawatts of Unisolar from 2003 to 2007. My Unisolar tests and installations exceeded PVWATTS kWh estimates by approx 5% (PVWATTS uses crystalline PV temperature coefficient). PVWATTS is a reliable estimator for crystalline PV systems when 0.65 dc-to-ac derate factor for battery based systems and 0.75 to 0.82 for batteryless systems was used. See http://www.uni-solar.com/uploadedFiles/0.4.2_white_paper_3.pdf a-Si degradation is no mystery. See http://www.nrel.gov/docs/fy00osti/28333.pdf NREL on-going tests since 1997 validates Unisolar's 20-year 80% warranty claim. It is interesting that the time of year Unisolar is deployed affects its light induced degradation. See "Recovery of Light Induced Degradation in Amorphous Silicon Solar Cells and Modules." I think that Unisolar modules are suitable: when high power density is not required if flexibility and/or conformability are wanted if partial shading is an issue if high cell temperature is an issue if building integration is wanted if no glass is wanted if its unique appearance is wanted. The "aluminum-frame-glass-module" monopoly has been broken. Unisolar's persistence, First Solar's CdTe success, and the re-appearance of CIGS (remember Arco/Siemens 1998 ST modules?) along with "see through" and other flexible PV modules is changing PV. The lowest price per watt (initial cost) is gradually giving way to lowest price per kilowatt-hour (lifecycle cost). It's still a neck-n-neck which PV technology will win, but there is no doubt that PV is winning almost everyone's heart and mind. Best regards, Joel Davidson "Not all change is for the better, but nothing gets better without change." So vote for change! ----- Original Message ----- From: jay peltz <mailto:[EMAIL PROTECTED]> To: RE-wrenches <mailto:re-wrenches@lists.re-wrenches.org> Sent: Friday, October 31, 2008 10:23 PM Subject: Re: [RE-wrenches] crystalline VS uni-solar Hi Joel, 1. unisolar 64's and sharp single cystal 2. SMA inverters 3. Arcata California 4. exact, I mean side by side with no shading, same azimuth ( south) same tilt ( can't remember) 5. As to the unisolar producing more, I must stress that I have never seen the Unisolar produce more than SC, never. jay peltz power On Oct 31, 2008, at 1:01 PM, Joel Davidson wrote: Hello Jay, Sounds like something is wrong other than Unisolar vs. crystalline. All things being equal, the Unisolar should produce more kWh per kW than crystalline. Questions: 1. What modules and how many of each? 2. What inverter or inverters? 3. Geographic location? 4. Array azimuth and tilt? Best regards, Joel Davidson ----- Original Message ---- From: jay peltz <[EMAIL PROTECTED]> To: RE-wrenches <re-wrenches@lists.re-wrenches.org> Sent: Friday, October 31, 2008 8:27:19 AM Subject: Re: [RE-wrenches] crystalline VS uni-solar Hi Geoff, In regards to the performance between Unisolar and crystalline, there is a side by side ( same watts, batteryless intertie with metering) installation up here on the North coast of California, and the the Unisolar is the constant under-performer. This includes cloudy, sunny, warm, cold weather. I have seen nothing in the field to support the Unisolar claims about better performance in low light etc. That said, they do work better in very hot conditions, if thats what you have. jay peltz power On Oct 31, 2008, at 8:08 AM, Geoff Greenfield wrote: As a follow up to my uni-solar post (and thanks to all who provided feedback), I have a second request: Any references to recent side-by side "shoot-outs" between Unisolar and conventional crystaline PV? Scientific studies? Your own wrench thoughts? I am more and more often encountering confused customers that are considering unisolar systems at zero-tilt (we are at 40 degrees N), with plenty of partial shading, after getting a pitch about all sorts of advantages of Uni-Solar. I think that this product has it's role and I occasionally sell it... But I am frustrated when I truly believe I can deliver a better net energy production with a tilted crystalline solution (avoiding the shaded areas). For a brighter energy future, Geoff Greenfield Founder and CEO Third Sun Solar & Wind Power Ltd. 340 West State Street, Unit 25 Athens, OH 45701 740.597.3111 Fax 740.597.1548 www.Third-Sun.com <http://www.third-sun.com/> Clean Energy - Expertly Installed _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org <http://www.members.re-wrenches.org/> _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org _____ _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
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