Day ahead irradiance forecast variability characterization using satellite data

In this paper we address the use of satellite-based irradiance data as a proxy for the ground irradiance data to determine the intraday solar variability as a function of a finite difference of hourly clear sky index, here after called nominal variability. The satellite data based nominal variability is compared to that of the ground data based variability to determine the use of satellite data as replacement for ground data for this application. A mathematical relationship has been developed to predict nominal variability as a function of the day's clear sky index. The article also demonstrates the application of the intraday variability to predict day ahead hourly forecast variability range as a function of the day's clear sky index. The results show that the intraday solar irradiance variability can be calculated using historical satellite data and provides a similar result to that of variability computed using quality historical ground data. The results also show the potential of intraday solar variability to characterize day ahead forecast variability.