ESTIMATION OF OPTIMUM TILT ANGLES FROM INCOMING SOLAR RADIATION FOR MAXIMUM PERFORMANCE OF PHOTOVOLTAIC SYSTEMS OVER NIGERIA

Abstract

Electricity demand across the world has continued to be the driving force that propels the economy. However, most regions without adequate access to electricity, including Nigeria, are regions with sufficient natural resources that can be developed to cater for their energy needs. Thus, the total energy demand of Nigeria could be met if a substantial portion of the total radiant solar energy radiant is converted using suitable solar technology. However, the incident power received on a photovoltaic (PV) module does not only depend on the intensity of sunlight, but also on the angle between the module and the sun (tilt angle). Thus, the optimum tilt angle of a PV module need to be accurately determined to optimize the total solar radiation received. In this research, the maximum global solar radiation and the corresponding optimum tilt angle was obtained for different geoclimatic zones in Nigeria, using direct, diffuse, and ground-reflected irradiances. The monthly results show that the maximum radiation is received at optimum tilt angles between 30° and 45° from October till February and between 15° and 30° from March till September for all the stations. Moreover, the seasonal results show that the maximum radiation is received in all the zones in MAM and JJA seasons at 15°, except Coastal Zone with a tilt angle of 45° during JJA season. Additionally, DJF and SON have maximum radiations at 45° and 15°, respectively. The result of the estimated monthly power revealed that Sahel Savanna and Sudan Savanna zones produced the highest power, which make them ideal for large-scale electricity production while the relatively low power in the Guinea and Coastal zones make them ideal for household and rural electrification. The results of this research will provide solar engineers with accurate information on the orientation and tilt of PV modules for efficient power generation.