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

Sat Nov 1 11:21:14 PDT 2008

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 installed, 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 <mailto:jay at asis.com>  

To: RE-wrenches <mailto:re-wrenches at 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 <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 <http://www.third-sun.com/> 

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