With time, the photovoltaic solar panels naturally soiled from dust and other elements. These soils prevent light to reach solar cell and can reduce the long-term profitability. The study demonstrates the soiling effect on the electrical characteristics of panels, productivity and performance. A model simulation was developed in this direction in order to quantify and compare the performance of clean and dirty panels, the dust particles have been considered as spheres with an elliptical shadow on the panel. The results prove a power loss of 40% of a 0,224 mg/cm 2 dust deposition in comparison with a clean panel at the maximum operating point MPP. This study describes the identified critical parameters governing the fouling of the PV panels.