Accuracy of Solar Irradiance Forecasts and Applications to Photo-Voltaic Power Systems Monitoring

The Global Weather Corporation (GWC) produces solar irradiance forecasts by combining output from various numerical weather prediction models and tuning the forecast to observational data. Forecast accuracy is analyzed at several sites that were not used in the forecast tuning.  The forecast accuracy in sunny climates is highest, and the most inaccurate forecast days are investigated. The accuracy of the GWC forecast from hours to six days in advance is shown for each site.  The accurate GWC irradiance forecasts can be used in applications for monitoring photo-voltaic power systems.