High resolution solar radiation database. Solar atlas for South Africa

Solar radiation data can be estimated at high spatial resolution over large geographical areas using satellite images. In this paper, two different satellite based methodologies have been applied to calculate global horizontal and beam normal irradiance values for South Africa. The accuracy of the estimates has been analyzed by comparing the modelled values with ground measurements recorded at thirteen stations distributed over the country. The best method results in an overall relative mean bias of 1.64% for the global horizontal irradiance and 2.93% for the beam normal irradiance estimation. This method has been implemented into an open GIS software that allows users to obtain for free, estimates of the available solar resource over large regions of their choice. In addition to this, the implemented methodology outputs the photovoltaic production of various PV technologies and different settings from fixed modules to sun tracking systems. The said estimation model takes into account the effect of the module's temperature, the cooling effect of wind, the angle of incidence to the module's surface and the spectral distribution of the received solar radiation. Furthermore, the GIS module contains high resolution terrain data that allows considering the effect of the surrounding topography on the above mentioned calculations.JRC.C.2-Energy Efficiency and Renewable