according to your answer exists geographical information software designed for this kind of work. Two of the most common are arcgis (lincensed) and qgis(open software). Unfortunately I am not an expert in its use but I know people of environmental engineering who use it for similar issues with biomass and hydraulic resources.
There are many GIS software available for mapping solar radiations of any specific location. Such as Spatial Analyst tool of Arc-GIS software as well as QGIS software. You can input your data in .CSV file format to map solar radiations according to your requirements.
Here are few links, hope you will find these links helpful.