Solyndra underperforms in Photovoltaic Module Test

solyndra-logoTEC-Institut-logo80Solyndra, Inc. cylindrical CIGS photovoltaic (PV) module loses to crystalline silicon in a head to head 12 month energy yield test conducted by the TEC-Institut.

Once again, a 97 character tweet, this time from EnergieMonster, launched a 1000 word (ah, 691 word) post:

Das Solyndra-Modul schneidet beim Test schlecht ab #pv about 16 hours ago via Facebook

The tweet points to the article with the same headline: “Das Solyndra-Modul schneidet beim Test schlecht ab” (German only, Google English) by Felicitas Pfuhl for EnBauSa GmbH, a German online magazine for energy efficient building and renovation also on twitter @enbausa!

The TEC-Institut für technische Innovationen test was conducted over a twelve (12) month period from March 1, 2009, through February 28, 2010, and the results are summarized in the June 2010 report:

Halten die Röhrenmodule was sie versprechen?
Vergleich der Jahreserträge des CIGS-Moduls “Solyndra” mit herkömmlichen PV-Modulen

translating to:

Do the tube modules deliver what they promise?
Comparison of the annual yield of the “Solyndra” CIGS module with conventional PV modules (Google English)

The TEC-Institut report (German only .pdf version can be downloaded here) compares the annual energy yield of the 182 Wp (Watt-peak) Solyndra SL-001-182 C, 100 Series CIGS (Copper Indium Gallium diSelenide) PV module versus 180 Wp multicrystalline silicon, 175 Wp monocrystalline silicon, and 40 Wp amorphous silicon (a-Si) modules at a test site located in Waldaschaff, Germany.

From the outset, the report claims the Solyndra module’s shadow blocked most if not all of the sunlight before hitting the reflector foil installed below the module, allowing only a small portion of reflected sunlight to hit the backside of the module. I wonder about the installation of the module with a like sized reflector foil though. While I assume Solyndra has a specification for the white roof margin required around their modules, the Fast, Easy, Cost-Effective Installations page of the Solyndra website makes no mention of roof preparation nor is an installation guide available for download.

Adjusting the kiloWatt-hours (kWh) generated by the kiloWatt-peak (kWp) capacity of each PV technology, the Solyndra module underperformed each of the other flat plate modules including a-Si over the year period.

TEC-Institut-monthly-module-data The Solyndra module only outperformed the silicon modules by a significant margin in the month of January 2010. Snow covered the PV modules and roof for extended periods in January. Solyndra outperformed because the snow melted from the Solyndra modules faster than the flat plate modules, and the roof snow increased the amount of reflected light reaching the back of the module. However, the one month had a minimal impact on the annual results. The TEC-Institut report goes on to claim the Solyndra module’s actual performance on an area basis was six (6) percentage points less than the expected results predicted from the datasheet specification normalized to the monocrystalline module. I’m not familiar with the TEC-Institut folks, so I’ll reserve judgment on their results, but I would prefer to see the raw, unadjusted data to double check that last calculation.

In addition to the Solyndra module shadow observation, the report concludes with a plausible concern about cleaning the reflective roof surface beneath the module a few times a year due to the central European weather conditions. In a large Solyndra flat rooftop array, how would the white reflective roof beneath the modules be cleaned, with a water hose?

If the report’s results are confirmed, is there really a market for a more expensive, easy to install, yet low performing PV module with higher O&M (Operations and Maintenance) expenses?

Please note Solyndra’s datasheet disclaimer may explain some of the performance variances:

*Product Specifications are only valid when using the product in accordance with Solyndra’s design and installation guidelines using Solyndra supplied mounts and interconnecting hardware. Product Specifications are subject to change without notice.

Also, ongoing improvements may already have boosted Solyndra production module performance since the test module was procured around February 2009. I’ve asked Solyndra about the report and expect they will respond as warranted once Father’s Day winds down.

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  1. Bret says:

    Fascinating stuff.. I’ve never installed Solyndra, though I’ve read about it. Why would O&M on a Solyndra system be more expensive?

  2. admin says:

    T.Schwarz, Dipl-Ing. Elektrotechnik and MSc Solar Energy submits:

    This "test" and the resulting report is questionable in many ways at best !!

    That report lacks the most elementary informations that any test report must give: what was measured (AC or DC), how it was measured (a list of equipment is certainly not enough, especially when looking at that equipment), in which system configuration the modules were operated, and at what angles (it only mentions once "teilweise ohne Aufständerung").

    Not to mention any formal things, like where the test was performed, not even where the Institut is located.

    And that "TEC Institut" and it’s staff present no references or qualifications that would qualify them to do such competent testing.

    Some things rather prove the opposite:

    – they placed the Solyndra panel "with the long side in N-S direction / mit der Längsachse in Nord-Süd-Richtung", while every reader of the Solyndra design manual could read that instead the tubes (which run at a right angle to the long side of the panel) should run in N-S direction for best yield in Northern latitudes

    – they claim that it is possible (even "common practice/üblich") to calculate the yield of a panel from its datasheet values… so nobody needs any sophisticated models and simulation tools ???

    Instead you can find that they are under one roof with the company ANTARIS Solar So this "Institut" seems to be nothing else than a pseudo-scientific arm of that company, with obvious purposes…

    So this "test report" should NOT be distributed any further as a supposedly independent report.

    I can assure that our Solyndra test system performed in a period of 15 months at the same level as a 25° tilted system with BP modules (see attachment).

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