Solar energy is the radiative energy that comes from the sun. Solar radiation is electromagnetic in nature and its spectrum cover the ultraviolet (UV) through the visible (VIS) to the infrared (IR) part of the electromagnetic spectrum. The data used in this study was a 12 years average solar radiation data between year 2009 and 2021. Monthly mean daily data of the extraterrestrial solar radiation (H ̅_0), global solar insolation on horizontal surface (H ̅) and averaged surface albedo (ρg) data were obtained from the National Aeronautic and Space Authority (NASA) Surface Meteorology Solar Energy (NASA surface meteorology Solar Energy, 2021). The model used to compute the total radiation on tilted surfaces is the Liu & Jordan Model. The optimal tilt angle for maximum collection of the solar insolation for Ilaro town is 120 for fixed module. However, the result of higher annual insolation than that at a fixed 120 can be obtained using a seasonal tilt.
