[RE-wrenches] crystalline VS uni-solar and beyond

Sun Nov 2 11:48:50 PST 2008

Geoff,

If you're going crystalline now, and have shading problems, this might be a
good system to consider the Enphase micro-inverter. No strings! Each module
delivers whatever it can and isn't affected by its neighbors. On the down
side, Enphase so far has only released models for 72-cell modules (24v
nominal) up to 180 watts, and just last week a new model for hi-volt Sanyo
HIP/HIT series up to 220 watts. You'll pay a bit more for inverters, but PV
performance is the best possible.

Cheers,
Doug Pratt 

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Geoff
Greenfield
Sent: Sunday, November 02, 2008 8:50 AM
To: RE-wrenches
Cc: RE Marketing for home scale RE industry
Subject: Re: [RE-wrenches] crystalline VS uni-solar and beyond

thanks everyone!  Once more this list is a fantastic resource.

As a follow up, the original post was related to mismatched strings... I
will be suggesting a design change to achieve consistant string voltages. 

More than any marketing claims, I trust this list's experience. I will be
proposing a crystaline alternative and will size it 5% larger. (I am
motivated to do this as this project has "special" laminates with foil and
Velcro, at 6.22/w! So much forcist advantage!  As full as this roof is,
plenty of that expensive pv is in shaded spots... Another reason my
crystaline alt would pwrfirm better. 

Regarding the pv watts modeling and the 5% advantage, did that include the
difference in tilt? I'm thinking that I'll have some additional gains with
10 degrees vs flat.   

For a brighter energy future,

Geoff Greenfield
President
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

Clean Energy - Expertly Installed

----- Joel Davidson <joel.davidson at sbcglobal.net> wrote:
> Hi Marco,
> 
> I'm moving this over to RE-Markets before I get my Send button punched.
> 
> I agree and am a crystalline guy for now. But if just 50% of the announced
thin film factories come on line and only half of the survivors match First
Solar's cost/price/profit, then other thin film wannabees a going to jump
in.
> 
> First Solar and SolarCity's recent deal is interesting. See
http://www.latimes.com/business/la-fi-solar30-2008oct30,0,3945811.story I
have not had much success finding enough space on home roofs for low-power
density PV.
> 
> Paul Basore and James Gee gave the definitive crystalline PV paper in 1994
(in your neighborhood!) and it still holds true. See
http://www.osti.gov/bridge/servlets/purl/10106636-scc2Rs/webviewable/1010663
6.pdf I think Paul is at CSG Solar (crystalline) and James is at Advent
Solar (crystalline).
> 
> Aloha,
> Joel
>   ----- Original Message ----- 
>   From: Marco Mangelsdorf 
>   To: 'RE-wrenches' 
>   Cc: 'Paula Mints' 
>   Sent: Saturday, November 01, 2008 11:21 AM
>   Subject: [RE-wrenches] crystalline VS uni-solar and beyond
> 
> 
>   Joel,
> 
>    
> 
>   I've been either a participant or observer of the PV field/industry as
long as most greybeards in the field.  And ever since my entry in the RE biz
in the 1970s, the promise from the touters of thin films has been: 1) their
product was going to revolutionize the industry, 2) their product was going
to dramatically lower the $/watt cost of PV and 3) their product was going
to replace that old fashioned and 1950s-vintage crystalline silicon as the
dominant semiconductor.in a few years, always in a few years.  And you know
what?  I'm still waiting for those oft-repeated claims babbled ad nauseum to
become reality.  Yes, First Solar is making great strides in establishing
CdTe as a viable segment of the market.  And yes, UniSolar has carved a
nice, and very small niche, in the market as well.  But if you look at the
still near dominance of crystalline (as in 85-90 percent) of the worldwide
PV market, I still conclude that when it comes to price, efficiency,
dollars/watt insta
 lled, reliability, longevity and unmatched operational time in the real
world, this talk of thin films being poised to take over is the same bunch
of hooey that it was in the 1970s, 1980s, 1990s and now.
> 
>    
> 
>   My two aloha cents worth..
> 
>   marco,
> 
>   ProVision, Hawai'i
> 
>    
> 
>    
> 
>   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 
> 
>     To: RE-wrenches 
> 
>     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 <jay at asis.com>
>     To: RE-wrenches <re-wrenches at 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
> 
> 
> 
> 
> 
> 