In this study, the energy generation of a solar panel in case of different surface contaminants is experimentally examined. The energy production of a solar cell is significantly influenced by the contamination of the panel’s surface. Not only the objects in the environment, but pollutants on the panel’s surface can also create a shadowing effect. The energy production and the efficiency of a solar panel are experimentally investigated in case of different types of contamination, such as sand, soil, cement, road salt and fly ash. Measurements are done with different polluted areas and the amount of pollution. A correlation between the power generation and the contamination is observed. Following the observation, it is possible to determine the loss of energy production, caused by the surface contaminants, while the optimal cleaning period can be determined. Power production and type of contamination show a certain amount of correlation. Since environmental factors directly affect the output voltage, it is possible to determine the voltage and power production drop depending on the surface contaminants.