You can take a look at “COMPARISON OF DEGRADATION RATES OF INDIVIDUAL MODULES HELD AT MAXIMUM POWER” from C.R. Osterwald, J. Adelstein, J.A. del Cueto, B. Kroposki, D. Trudell, and T. Moriarty, National Renewable Energy Laboratory (NREL), Golden, CO 80401

http://www.photonenergysys.com/osterwald%20wcpec.pdf

(specifically, the tables on the last page).

While I disagree with some of their results, they do show that CdTe degrades 1.3% a year (8 years of exposure) or, in the second table, 1.84% a year (10 years of exposure). Amorphous silicon thin-film’s degradation is generally about 1% or higher as well (more recent results for Unisolar, for example, from the same studies show 1.24% degradation under STC). Crystalline (x-Si or poly-Si) degradation is generally 0.5% a year.

[SK: great: thanks]

You can take a look at “COMPARISON OF DEGRADATION RATES OF INDIVIDUAL MODULES HELD AT MAXIMUM POWER” from C.R. Osterwald, J. Adelstein, J.A. del Cueto, B. Kroposki, D. Trudell, and T. Moriarty, National Renewable Energy Laboratory (NREL), Golden, CO 80401

http://www.photonenergysys.com/osterwald%20wcpec.pdf

(specifically, the tables on the last page).

While I disagree with some of their results, they do show that CdTe degrades 1.3% a year (8 years of exposure) or, in the second table, 1.84% a year (10 years of exposure). Amorphous silicon thin-film’s degradation is generally about 1% or higher as well (more recent results for Unisolar, for example, from the same studies show 1.24% degradation under STC). Crystalline (x-Si or poly-Si) degradation is generally 0.5% a year.

[SK: great: thanks]

Do you have a link to the NREL research? I will fix the post if that is wrong. These posts bounce around the internet forever, and I certainly don’t want to spread around an incorrect statement.

Yeah, you are right about the extra labor for thin-film – at least on roofing. You have to practically install it in a lab to keep grit and dust from getting between the thin-film and the roof.

Do you have a link to the NREL research? I will fix the post if that is wrong. These posts bounce around the internet forever, and I certainly don’t want to spread around an incorrect statement.

Yeah, you are right about the extra labor for thin-film – at least on roofing. You have to practically install it in a lab to keep grit and dust from getting between the thin-film and the roof.

Your statement that lower “efficiency” of thin-film tends to go along with lower degradation over time is plain false. Numerous studies, including ones done by NREL and European research insititutions, have documented that. For example, Tucson Electric’s data have shown that First Solar’s module degrade over 1.5% a year, while crystalline modules degrade about 0.5% a year. And First Solar’s modules are one of the least-degrading thin-film modules.

Also, yes, thin-film PV modules are cheap, but system costs per Watt are comparable to those of regular crystalline modules. It is not just the larger area required by the thin-film modules – it is also numerous other balance-of-system costs that are higher for thin-film, such as wiring, mounting solution, installation labor, etc.

Your statement that lower “efficiency” of thin-film tends to go along with lower degradation over time is plain false. Numerous studies, including ones done by NREL and European research insititutions, have documented that. For example, Tucson Electric’s data have shown that First Solar’s module degrade over 1.5% a year, while crystalline modules degrade about 0.5% a year. And First Solar’s modules are one of the least-degrading thin-film modules.

Also, yes, thin-film PV modules are cheap, but system costs per Watt are comparable to those of regular crystalline modules. It is not just the larger area required by the thin-film modules – it is also numerous other balance-of-system costs that are higher for thin-film, such as wiring, mounting solution, installation labor, etc.

Does this only apply to cadmium telluride or is it for all thin film products ?

Also , what is your source for this longevity info ?

[SK: I'm pretty sure it applies to thin film generally. My source: last Fall I took the solar classes run by PG&E at the Pacific Energy Center which I highly recommend. They are actually free and super concentrated and very comprehensive.]

Does this only apply to cadmium telluride or is it for all thin film products ?

Also , what is your source for this longevity info ?

[SK: I'm pretty sure it applies to thin film generally. My source: last Fall I took the solar classes run by PG&E at the Pacific Energy Center which I highly recommend. They are actually free and super concentrated and very comprehensive.]