Comparison of satellite-retrieved high-resolution solar radiation datasets for South Africa

Abstract

This study compares the performance of two satel-lite-based solar radiation methodologies for estimat-ing the solar resource available in South Africa. Data from thirteen stations distributed in six climatic re-gions were considered. More than one year of hourly values of global horizontal and beam normal irradiance were examined in the validation of the satellite-retrieved estimates at every location. The best satellite method resulted in an overall relative mean bias of 1.41% for the global horizontal irradi-ance corresponding to almost 3 Wm-2 and exhibited a relative mean bias of 2.85% for the beam normal irradiance estimation (about 7 Wm-2). This satellite-based method was implemented into a geographical information system module, which contained high-resolution terrain data and allowed the effect of the surrounding topography on the estimation of the available solar resource to be considered. These es-timates can, therefore, be used as input data for fur-ther analysis or applications. As an example, maps of the potential output that could be expected in South Africa from photovoltaic systems were cre-ated.