Identification of Sites for Solar Power Plants in Sri Lanka Using Solar Radiation and Cloud Cover Analysis

With the increasing energy demand in Sri Lanka, the most appropriate locations for solar power plant installation were identified integrating Remote Sensing, GIS, and the Analytical Hierarchy Process (AHP), focusing on factors such as solar radiation, cloud cover, slope, land cover, and proximity to main roads, grid connectors, transmission lines and rivers. In particular, cloud cover, an often-overlooked factor in solar energy potential evaluation, contributed a significant improvement to previous methodologies. MODIS, Sentinel-5P, Sentinel-2, SRTM DEM, OpenStreetMap, Ceylon Electricity Board (CEB) and Sri Lanka Sustainable Energy Authority (SLSEA) datasets were processed to derive the key findings, which highlight the Northern, North Central and Eastern provinces prospects for high solar energy. The pairwise comparisons were assisted by feedback from approximately 30 professionals, including doctoral candidates, lecturers, electrical superintendents, and site engineers from the CEB, various solar companies and universities. The resulting map was classified into Highly Suitable, Suitable, and Moderately Suitable regions. The analysis confirmed that optimal sites overlap with high solar radiation, low cloud cover, and flat or gentle slope areas. Solar radiation validation was conducted by comparing Global Solar Atlas data for 2018, due to the unavailability of recent datasets, achieving a correlation coefficient (r) of 0.9715, an R2 of 0.9438, and a Root Mean Squared Error (RMSE) of 30.72 W/m2. For cloud cover, a comparison between Global Cloud Cover and Sentinel-5P, resulted in an r value of 0.8523, an R2 of 0.7282, and an RMSE of 0.04. Land cover accuracy assessment through Google Earth Pro and ArcMap achieved an 81% overall accuracy and a 0.74 kappa coefficient value.