According to some embodiments, the present disclosure may include a method of analyzing solar power forecasts that may include obtaining a test dataset of historical irradiance at a location of a solar power generating system, and normalizing the test dataset based on a clear sky model at the location. The method may also include clustering the test dataset into multiple weather classes that each include a set of characteristics, obtaining a forecast of irradiance at the solar power generating system, and classifying the forecast into one of the weather classes, and determining confidence intervals of the forecast based on the set of characteristics of the one of the plurality of weather classes. The method may additionally include, based on the confidence intervals of the forecast, performing one of increasing output or decreasing output of a source of energy alternative to solar energy.
