Modelling of real solar radiation spatial distribution as a tool for solar energy cadastre in the cities

The increasing needs of energy and decreasing traditional energy sources are becoming one of the biggest issues of our civilization. The provision of stable energy supply is a matter of state security. The energy consumption keeps growing especially in big cities. Therefore, it became reasonable to produce energy directly in cities. To optimize the use of the solar energy in the city areas, a fundamental issue is to find and estimate the amount of solar radiations at a specified location by using available tools and data. The main goal of this work is to demonstrate the potential of the r.sun model, a component of GRASS software, in calculating real solar radiation for the selected location. The work starts with demonstrating the effect of cloud cover for the amount of solar radiation reaching the Earth’s surface and the usage of GIS software and Ogimet website in the spatial analysis of real solar radiation distribution. For this purpose, data concerning cloud cover for selected locations were analysed. The study is based on the synoptic data obtained from Ogimet. Average daily cloud cover totals and long-term values were calculated. Apart from the cloud cover data, a significant variable, the Linke turbidity factor, describing the weakening of solar radiation due to the presence of aerosols and water vapour in the atmosphere, was taken into consideration. The obtained results were used to develop a map of real solar radiation distribution for a part of Wrocław. The results obtained by that model with the acquired data by the local meteorological station show compatibility.