News Brief

New PV Rating System Models Real-World Test Conditions

By Erin WeaverA new rating system for photovoltaic modules aims to improve upon standard test conditions (STC) by more fully reflecting real-world variations. The Principal Solar Institute (PSI), created by solar energy holding company Principal Solar, Inc., has introduced the PSI PV Module Rating to help the commercial and utility-scale markets compare the performance and cost of modules.

Compared to STC, which uses a constant light intensity at a fixed temperature, PSI models daily variations in light and temperature, as well as five other factors, to calculate total expected energy production over a module’s 25-year lifetime. Ratings for 500 modules are available on PSI’s website, with 10,000 more available upon request.

Published November 29, 2012

Weaver, E. (2012, November 29). New PV Rating System Models Real-World Test Conditions. Retrieved from

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