Long-term outdoor assessment of dust deposition impact on optimal tilt angle, efficiency, and operating temperature of photovoltaics

The role of decentralization in decarbonizing the grid by focusing on the effective deployment of localized, roof-installed PV systems, is here considered by addressing the impact of dust in large cities. An analysis of 8 months of outdoor experimental data is conducted to study the impact of dust deposition on the optimal tilt angle and overall efficiency of PV systems. The accuracy of existing theoretical models for optimal tilt angle is tested, and the effect of a specific natural phenomenon, a dust storm, is also explored. The optimal tilt angle increased significantly to compensate for the reduced solar irradiance caused by dust accumulation on the modules and after the dust storm, the clean modules exhibited a higher temperature compared to the dusty modules. The degradation in efficiency due to dust accumulation is primarily attributed to the decreased solar radiation absorption, while temperature changes in the modules do not play any significant role for this parameter. It was also verified that the currently available theoretical models are not satisfactory in accounting for dust deposition, and need substantial improvement that could lead to further generalization. The obtained results are not only applicable to the specific testing location but can also be generalized to other regions affected by dust storms and to semi-arid climates more broadly.