Two-State Markov Model of Solar Radiation and Consideration on Storage Size

This paper proposes a two-state Markov model to determine the storage size of a photovoltaic system. The system is usually connected to a distribution grid, but once a large disaster occurs, it becomes the main source of supply. Daily solar radiation changes due to the weather, and it could become lower than a specified supply level for a sequence of days. Transition probabilities are determined from meteorological data on the solar radiation. The Markov model shows that its frequency exponentially decreases as the sequence becomes long. One or two days of storage is adequate to reduce the number of insufficient supply days to an acceptable level, and the value of adding the storage exponentially decreases, too. Some simulations and experiments are executed to verify these facts.