The Principal Solar Institute Module Ratings

The Principal Solar Institute’s scientifically designed and certified combination of tests and performance standards provide an unbiased, comprehensive rating system – the PSI PV module rating. Seven essential characteristics related to initial and long-term PV module performance are combined to create the PSI Rating:

• Actual Tested Maximum Power vs. Advertised
• Temperature Coefficient at Maximum Power
• Power at Low Irradiance to Power at High Irradiance Ratio
• Normal Operating Cell Temperature (NOCT)
• Total Area Efficiency
• Negative Power Tolerance
• Annual Power Reduction

These ratings allow you to make comparisons when analyzing PV modules and help you select the optimal PV module.

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PSI Ratings – PV Solar Modules from Stion

Here are the PSI Ratings for modules from Stion, calculated based on initial performance test data. If you don’t see a solar module that you are considering, contact us and we will try to add it.

Rank	Manufacturer	Model	Type	Power (W DC)	PSI Rating	Percentile
1	Stion	STO-150	Thin Film	150	7.67*	58
2	Stion	STL-150	Thin Film	150	7.67*	58
3	Stion	STO-145	Thin Film	145	7.60*	54
4	Stion	STL-145	Thin Film	145	7.60*	54
5	Stion	STN-150	Thin Film	150	7.46*	45
6	Stion	SN-150	Thin Film	150	7.40*	41
7	Stion	STO-140	Thin Film	140	7.32*	37
8	Stion	STL-140	Thin Film	140	7.32*	37
9	Stion	STN-145	Thin Film	145	7.19*	30
10	Stion	SN-145	Thin Film	145	7.14*	27
11	Stion	STO-135	Thin Film	135	7.08*	25
12	Stion	STL-135	Thin Film	135	7.08*	25
13	Stion	STN-140	Thin Film	140	6.97*	20
14	Stion	SN-140	Thin Film	140	6.92*	18
15	Stion	STO-130	Thin Film	130	6.85*	16
16	Stion	STL-130	Thin Film	130	6.85*	16
17	Stion	STL-125	Thin Film	125	6.59*	9
18	Stion	STO-125	Thin Film	125	6.59*	9
19	Stion	STN-135	Thin Film	135	6.51*	8
20	Stion	SN-135	Thin Film	135	6.46*	7
21	Stion	STN-130	Thin Film	130	6.28*	5
22	Stion	SN-130	Thin Film	130	6.23*	5
23	Stion	STN-125	Thin Film	125	6.03*	3
24	Stion	SN-125	Thin Film	125	5.99*	3
25	Stion	STN-120	Thin Film	120	5.78*	3
26	Stion	SN-120	Thin Film	120	5.78*	3
27	Stion	SN-115	Thin Film	115	5.55*	2
28	Stion	STN-115	Thin Film	115	5.54*	2
29	Stion	STN-110	Thin Film	110	5.32*	2
30	Stion	SN-110	Thin Film	110	5.29*	2

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* Modules denoted with an “*” use estimated values for one or more characteristics. Manufacturers can contact us to provide the missing data for these PV modules.

NOTE: PSI Ratings are based on publicly available data, and are subject to change as additional data and proprietary analyses become available for long-term performance.