Performance monitoring of a 60 kW photovoltaic array in Alberta

Solar photovoltaic (PV) systems are relatively new and there is not a large amount of performance data available for them with which to compare design calculations. This comparison is also necessary to provide confidence that newer systems will perform as predicted. This chapter describes a year's monitoring of a 60 kW PV system near Strathmore, Alberta, latitude 51°, installed in November 2016. The modules were flush mounted to a roof with 8° of pitch. There was no shading and the installation was near an Alberta Department of Agriculture meteorological station which provided the weather data. The measured capacity factor was 13.8%, and there was a loss of 11%-12% of the yearly production to snow. We demonstrate that satellite-based production forecasts of the array irradiance underestimated the solar resource at this location. The predictions of actual energy production from two different modeling tools showed that the more detailed System Advisor Model software was more accurate than RETScreen.