Performance analysis of power output of photovoltaic systems in San Diego County

Performance of photovoltaic (PV) systems installed in Southern California is analyzed. Measured power output of 400 PV sites, measured irradiation at 5 stations, and satellite-derived irradiation data are applied. Performance of the PV systems is estimated by using the satellite-derived irradiation data. Also, clear sky indices (kt) are obtained and compared for all these datasets. Over one year the largest hourly ramp was a 61% decrease based on the STC rating. The measured and satellite derived irradiation data are applied to evaluate the predictability of ramps. The effects of specific meteorological conditions, such as coastal marine layer clouds and frontal system effects, on occurrence of large ramps are investigated over the area. Satellite images are utilized to detect the weather condition for the days in which the ramps occurred.