Fundamental studies on dust fouling effects on PV module performance

•The effect of dust fouling on PV module performance has been studied.•The PV module power output has been reduced by 6% after 5weeks of exposure.•The glass cover transmittance has been reduced by 20% after 45days of exposure.•Dust particles adhesion on flat surfaces increase with increase in particle size.•Humidity promotes the adhesion between dust particles and glass surface. This paper presents the results of study on the effect of dust fouling on the transmittance of PV module glass cover. The study included the effect of dust fouling on overall plane glass transmittance, spectral transmittance of anti-reflective coated glass and characterization of the physical and chemical properties of dust particles. Also, micro-adhesion forces of dust particles on flat glass substrates are included. The results indicated a 20% reduction in glass transmittance and a 5g/m2 of dust accumulation on the glass cover of PV modules tilted at 26° (Lat of Dhahran) and exposed for 45days. The anti-reflective coated glass exhibited less reduction in transmittance compared to non-coated plane glass. The adhesion forces of particles on flat surfaces increased with increase in particle size due to increase in contact area between the particles and the surface. At high humidity level there is an increase in the vertical adhesion due to the generated capillary forces between dust particles and glass surface.