Empirical Modelling of Dust Accumulation Effects on Photovoltaic Module Performance in the Nigerian Sahel Zone

Background: Dust soiling of PV modules in the Sahel zone of North East and North West Nigeria is a major but incompletely quantified energy yield loss mechanism. Empirical models that relate dust accumulation to performance degradation are essential for maintenance scheduling. Aim: This study empirically modelled the effect of dust accumulation on PV module performance in the Nigerian Sahel zone, using field data from Maiduguri, Kano, and Sokoto. Methods: Sixty PV modules were deployed at three sites in natural and controlled dust accumulation trials. Module performance was characterised at 0, 7, 14, 21, and 30 days without cleaning using an I-V curve tracer. Dust mass density on module surfaces was gravimetrically measured. Particulate composition was analysed by XRF. Results: Power output declined linearly with dust accumulation at a mean rate of 1.7% per g/m2 in the dry season. Thirty-day unclean modules showed mean efficiency losses of 23.4% in Maiduguri compared with 14.1% in Kano and 18.7% in Sokoto. Harmattan season deposits were dominated by silica and iron oxide particles with mean particle diameter of 8.4 micrometres. Conclusion: Weekly module cleaning is recommended during Harmattan season in the Sahel zone to limit dust-related yield losses. An empirical dust model parameterised by location is provided for incorporation into PV performance simulation tools. Keywords: dust soiling, photovoltaic, Sahel, Harmattan, performance modelling.