Flash Test Data [RE-wrenches]

[Antony Tersol]

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IF each module IS flash tested what is the exuse for the -/+ 5-10% warrantys?  Isn't that just a way for the manufacturers to overcharge for what they are delivering?  If  -0%/+whatever% was required, the manufacturers could sort their modules into groups of modules that were much more closely matched, improving overall performance of each installation, and making it more likely the actual performance would meet expectations.

In California, the new CSI program bases incentives on "Expected Performance".  Yet their EPBB calculator uses STC rather than PTC ratings (despite PTC being regarded as a better predictor of installed performance), and uses the manufacturers nominal rating when the warranteed rate is often much less.  [http://www.csi-epbb.com/]

For example, one manufacturer's Limited Power Warranty says "... a power output less than 90% of the Minimum Peak Power (1) ... "
"(1) “Minimum Peak Power” = Peak power minus the Peak power tolerance..."

So for a -5%/+10% tolerance warranty they are promising to be within 10% of 95% of the nominal rating - for a module sold as 205 watts they're promising you'll get 175 watts, almost 15% less. 

And if it's a -10%/+10% it's 19% less.  Both of these drops are bigger then incurred by installing the modules flat instead of at optimum tilt to the south!  

Since priced by the rated nominal watt, the customer can end up paying for more then they get.  Since priced for 205 watts, if the module only delivers 175 watts, the real cost is (205 - 175) /175 = 17% more per delivered watt.  And as installers, you have customers getting 15% less production then expected.

Ahh, but you say, "how about the +10%?  The customer might get more then they expected!"  Well yes, they might, but do you expect that manufacturers rate their modules according to the average rate, or the best they get?  Which leads to more revenue?  And even if some of the modules have a higher rating, production in a string is determined by the module with the lowest rating.  

"Won't market forces reward the best and punish the worst?".  If quality isn't brought to the fore prior to the purchase, how can it influence behavior?  

A large part of our task is educating potential clients.  Try explaining to a client why the official program's "Expected Performance Based Buydown Calculator"  is mistaken in predicting production using STC rating.  And try to convince the client that the system with a higher PTC rating, but lower EPBB production estimate is better than a competitors system with a lower PTC rating, but higher EPBB production estimate.  Wouldn't the client tend to think the "official" rating is the one to believe? 

By the time the customer is experiencing lower production then promised it is too late.  The competitor is gone, out-of-business, or merged into one of the new PV marketing conglomerates.  Shades of the '80s?

If the programs reward overselling and underdelivering, don't be surprised if that is what results.  

The CSI program has introduced an order of magnitude more work for the installer for compliance, over differences in ratings of a few percentage points.  All to "ensure the best possible performance".  

Why introduce a huge amount of bureaucracy to chase after a few percent of expected production differences, while letting 15-19% slip through the STC/PTC/tolerances crack (more like a gaping hole)?

[Compared to the old program, CSI greatly increases the amount of paperwork, site-surveying, and inspection, while making the rebates sensitive to the "Expected Performance" due to geographical factors (location and weather) and design factors (tilt, azimuth, shading).  They've chosen an arbitrary reference location, such that other locales are penalized if they have worse expected production, but locales with better expected production are not rewarded.  And they've created more work for the administrators - more forms to enter, more things to check, more inspections - so much so that it has been reported that not one single system has been approved and connected under the new program.]  

Best way to improve performance: tighten up the quality requirements.  The relationship between STC and PTC is established; PTC is regarded as a better predictor of installed performance.  Make sure the customer is getting the STC for which they're paying, and  within tighter tolerances, and the performance of the systems will be improved.     

Require that each module be tested, and mandate a -0% delivery warranty!  There are _some_ manufacturers who so warrant.  But if it isn't required, then those that use "smoke and mirrors" guarantees are rewarded.

Best way to get industry-wide warranties that better protect the consumer?  Have the California program require it.  Have you noticed the 10 year warrantys the inverter manufacturers are offering? 

Antony Tersol
Applied Solar Energy




jay peltz wrote

"Date: Sat, 16 Jun 2007 17:46:11 -0700
From: jay peltz <jay at asis.com>
Subject: Re: Flash Test Data [RE-wrenches]



HI Joel,

Given that each module IS flash tested and referenced to the serial  
number I can't believe that it would cost much to produce that via  
email or paper copy on the module or some other form.

And given that ratings are -/+ 5-10%, well wouldn't you want to know  
if you are getting what you are paying for?

Thanks,

jay
peltz power"


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