Evaluation of PV system performance of five different PV module technologies

Based on the outdoor test PV power plant near Zurich the performance regarding single module and grid connected string of five different cell technologies has been analyzed and compared to indoor measurements. Good correlation between indoor and outdoor behavior has been shown for irradiance around 1000W/m2. For multi c- Si, mono c-Si and a-Si/?c-Si the determined performance values agree within ±2% between indoor and outdoor measurement. Regarding the lowlight performance, evaluation depends on the irradiance reference sensor. While the performance is well determinable regarding self-reference to ISC using c-Si based reference cells shows increasing instability towards lower irradiance due to spectral mismatch. Nevertheless the c-Si reference cell based model has proven to predict energetic output of single module well below measurement uncertainty within ±0.6% for all technologies for the analyzed timeframe and revealed problems in the inverter’s maximum power point tracking