How much do PV cells degrade with time?
Note: Further information requested. There are several ways to approach this question. First note that many of the larger manufacturers are offering 20 year warranties on their modules. The warranties are typically against complete failure, not against slowly falling output. Some companies warranty 90% of rated output for N years and 80% for M years, with various M and N. Second there are the results of lab tests. TISO in Switzerland is one of the few organizations I know who have posted material on the subject. See: TISO – PV Module Testing See also: • (PDF) Commonly observed degradation in field-aged Photovoltaic Modules by M. A. Quintana et al. 11A) How much do PV cells degrade with rising/falling temperature? The electrical output of PV cells are specified for a given temperature (usually +25C). The behaviour when the temperature rises above or falls below the optimum given by the manufacturer depends upon the physical properties of the photovoltaic material used. As a general rule
