The Principal Solar Institute aims to provide an unbiased comparison of PV modules by creating a comprehensive PV module rating standard called the PSI Rating. The PSI Rating is based on a module's 25-year lifetime energy production, calculated using seven key characteristics that impact energy output like power at different irradiance levels and temperature coefficients. It analyzes published data for over 10,000 modules and assigns a rating along with a percentile rank to help customers choose the best module for their application.

1. Presents
PSI Ratings for PV Modules

2. Our Mission
 Our mission is to answer
ESSENTIAL QUESTIONS…
 What is the best PV module for my application?
 Where can I get an unbiased comparison
of PV modules?
 Which PV module produces the most energy?
…and provide online resources for PV module
installers, developers, financiers and investors.
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3. It’s About Time
 The PV module marketplace is littered
with brochures and datasheets;
drawing comparisons and making good
decisions is complicated…
…The Principal Solar
Institute has the solution.
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4. Module Rating
 The Principal Solar Institute has created
the first comprehensive PV module
Rating Standard.
 The PSI Rating is based on PV module
25 year Lifetime Energy Production − LEP.
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5. Seven Essential Characteristics
Actual Tested Maximum
Power at Low Irradiance to Power vs. Advertised
Power at High Irradiance Ratio Temperature
Coefficient at Maximum Power
Total Area Nominal Operating
Efficiency Cell Temperature
(NOCT)
Annual Power
Negative Power Reduction
Tolerance
 Impact on Lifetime Energy Production
is the basis of the PSI Rating
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6. PSI Rating Example
 We analyze published data for over ten
thousand PV modules, calculate the LEP
and generate the PSI Rating.
Model PSI Percentile
Manufacturer
Number Rating Rank
SunPower SPR-34… 11.2 1.00
Ningbo Ulica UL-29… 10.6 1.00
This sample from the PSI
Rating database shows how
GCL-Poly (Suzhou) GCL-P6… 9.9 1.00
combined characteristics are
Ningbo Ulica UL-28… 9.9 1.00 used to rate different PV
SunPower SPR-39… 9.8 1.00 modules.
Sanyo Electric HIT-N2... 9.4 0.99
Sanyo Electric HIP-21… 9.2 0.99
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7. Rapidly Changing Marketplace
 PSI Ratings are “certified” for modules where our database has all seven
performance characteristics of PV modules. For modules denoted with
an “*”, we use estimated values for one or more characteristics. More
PV modules will become “certified” as PSI compiles accurate test data.
 Follow us on Twitter @PrincipalSolar for updates. PV Module
manufacturers can contact us at info@principalsolarinstitute.org to
provide data for PV modules not yet listed or not certified.
 PSI is working with TUV Rheinland, the world’s leading solar module
testing lab, to incorporate accelerated testing data into the PSI
Ratings. An eighth characteristic – Failure Rate – will be included in our
next release.
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8. Concentrating the Power of Solar
 Focusing the power of experts from across
the solar power industry, including
manufacturers, scientists, installers,
developers and financiers, to forge an
unbiased and comprehensive PV module
rating standard—
—The PSI Rating
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9. Thank you.