Experimental and Theoretical Analysis of Dust Soiling and Its Effect on PV Module Performance in Kano

Dust deposition on photovoltaic module surfaces reduces transmittance of the glass superstrate and degrades module power output, representing a significant energy loss in arid and semi-arid regions of Northern Nigeria. This study combines experimental characterisation of dust soiling with theoretical modelling of its optical and electrical impact on PV module performance in Kano, North West Nigeria. Module surfaces are instrumented with tipping bucket sensors to measure soiling rate, and sequential optical transmittance measurements are performed on glass coupons exposed outdoors for 1, 2, 4, 7, 14, and 30 days using a spectrophotometer. The mass, particle size, and mineralogical composition of deposited dust are characterised by gravimetry, laser diffraction, and XRD analysis. An analytical model relating dust mass loading to optical transmittance reduction and short-circuit current degradation is derived and validated against measured I-V curve parameters from eight co-located test modules. Results indicate an average soiling rate of 1.4 grams per square metre per day during harmattan, with transmittance losses of 18.3 percent and Pmax reduction of 21.7 percent after 14 days without cleaning. The model achieves prediction accuracy within 4 percent of measured values. An optimal cleaning interval of 7 to 10 days is recommended for Kano installations to maximise net energy yield. Keywords: soiling, photovoltaic, dust deposition, Kano, module performance