Estimating the global solar radiation for solar energy projects - Egypt case study

The main objective of this paper is to determine the best models for estimating the global solar radiation (GSR) on a horizontal surface over Egypt. A model selection criterion is used to determine the best model for each site. A general two-stage method is developed. In the first stage, 40 popular empirical models are evaluated for a specific set of sites in Egypt. In the second stage, Egypt is divided into a set of regions each of which is described by the best found GSR model. The determined regions and regional models are based on the results of the first stage and determined based on the determined best model for the sites contained in a specific region. The results show that the solar radiation over the whole lands of Egypt can be characterised by two models: the Iranna and Bapat 10P GOB 1 and the Kilic and Ozturk.