Investigation and Determination of Optimal Tilt Angles and Solar Radiation Gains for Fixed and Tracked South-Facing Solar Photovoltaic Surfaces in Provinces of Turkiye

The solar photovoltaic (PV) plants in Turkiye have been advancing at a remarkable rate in the last decades because of the region's high solar energy potential. However, it is understood from the literature review that there are still limited research works on the optimization of the tilt angles of PV surfaces to maximize the solar radiation of the PV energy systems in this region. Therefore, this study focuses on a quantitative analysis of the optimal tilt angles of south-oriented PV surfaces and the amount of solar radiation collected by optimally tilted and tracked PV surfaces for all provinces by using the National Aeronautics and Space Administration-Surface meteorology and Solar Energy (NASA-SSE) horizontal radiation data for the provinces in Turkiye. Also, a numerical method is proposed to estimate the average daily solar radiation values falling on optimally tilted and tracked PV surfaces in 81 provinces and 7 geographical regions of Turkiye in this paper. An optimal tilt angles map has been created for all provinces where solar plants could be established. Solar data calculations have been carried out for all provinces, and the results are presented for the average total radiation amounts and percentage contributions that can be obtained in the case of installing fixed systems and tracking systems. It is found that the tilt angles of all provinces and regions are below the latitude values of Turkiye (36 degrees ' N-42 degrees ' N). Annual fixed optimal tilt angle values for south-facing PV surfaces are found between 28 degrees and 36 degrees throughout the year. It is observed that the daily average total radiation values falling on PV surfaces are considerably affected by the geographical and climatic characteristics even between the provinces with close latitude values in Turkiye. The results indicate that the tracking systems provide remarkable solar energy gains compared to the annual fixed systems. The proposed methodology can be used in the case of the implementation of a large-scale PV plant in any location in Turkiye, and this knowledge can be extended to the world thanks to low computational cost.