An Optimized Approach for Mapping Solar Irradiance in a Mid-Low Latitude Region Based on a Site-Adaptation Technique Using Himawari-8 Satellite Imageries

Abstract

Solar technologies play an important role in the renewable electric energy budget, so accurate solar maps are a crucial point for finding a suitable place for solar panel installation. This study proposes a method for solar irradiance mapping in mid-low latitude regions, and the method’s site-adaptation process is performed by optimizing the Heliosat method through the REST2 clear-sky model, cloud albedo selection, new clear-sky index, and linear subtraction for bias removal. A local station with two pyranometers provided measurements for this method. Site-adapted model results were used to create a calibrated solar map by linear regression adaptation. This study also provides the evaluation and site-adaption of another known irradiance dataset in the Asian region from the Japan Aerospace Exploration Agency (JAXA). Heliosat model results with optimal cloud albedo showed high accuracy of 4.78 MBE and 63.11 RMSE, which can be improved using the site-adaptation process to 0.71 MBE and 57.42 RMSE. The selection of an optimal cloud albedo improved the model by more than 20%. The JAXA dataset obtained a large overestimation of 56.72 MBE, thereby highlighting the importance of site adaptation. This research’s findings pave a new way for the creation of accurate site-adapted solar maps and databases.