Performance Ratio (PR) and Energy Yields (Ey) are the two indicators define the long term field performance of PV modules arrays. PR a dimensionless number quantify the losses over the DC rated power of module and Ey having unit of hours or kWh/ kWp quantify energy generated per kWp installed of PV array. These two parameters solely depend on site temperature, sun spectral contents and solar cell spectral response (SR), play very significant role in the overall energy yields from PV power plants. With a view to understand variations in PR values with technology, site, season and also due to self deterioration in PV modules during exposure, outdoor test beds for matured major technology modules are set up at SEC . The module technologies studied include mono, multi and amorphous silicon single & tandem junction modules, thin film poly crystalline modules CIS & CdTe/ CdS and HIT. The dates of installations and amount of outdoor exposure given are different for different modules, varied from one year, 7 years and 10 years. Major observations are, losses in PR varied with technology and time. A maximum up to 5% in one year and minimum up to 17% in ten years are observed. The degradation in PR are presented with deterioration in PV module performance parameters short circuit current (Isc), open circuit voltage(Voc), fill factor(FF), power output(Pmax).

26th European Photovoltaic Solar Energy Conference and Exhibition; 3590-3591