Coarse Dust Soiling and Fine Dust Dimming Effects on PV Panels Over the Arabian Peninsula

Dust profoundly impacts the environment, climate, air quality, and human health in dust-source regions like the Middle East, which receives a record amount of solar radiation. However, dust could significantly hamper the efficacy of solar devices. The impact of aerosols on, e.g., photovoltaic (PV) panels is twofold. Firstly, aerosols suspended in the atmosphere attenuate solar radiation reducing the downward solar flux at the surface. Secondly, dust and other aerosols deposit on the optically active surfaces of solar devices, decreasing their efficacy. The total loss can be calculated as a sum of soiling and attenuation losses. This study investigates the impact of coarse and fine dust particles on the PV panels' efficacy using WRF-Chem model simulations and observations of dust deposition, aerosol optical depth, and incoming solar irradiances. Fine dust particles with radii $\mathrm{r} < 3$ um are mainly responsible for significantly reducing the downward solar flux. However, dust mass deposition on PV panels is primarily linked to coarse particles with $\mathrm{r} > 3$ um. The average surface solar radiation decrease caused by dust over the Arabian Peninsula is more than 10 W m ⁻² . Still, locally, it exceeds 40 W m ⁻² . Thus, the average daily attenuation loss is about 3-4%, but locally reaches 10–12 %. The deposited particles are densely packed on the surface of a PV panel, and the Mie theory is not applicable to evaluate their radiative effect. Here we suggest that deposited particles make a uniform layer over a solar panel surface. The estimate of soiling losses based on this assumption agrees with observations, suggesting that soiling losses are caused mainly by coarse dust. The average soiling losses over the Arabian Peninsula are accumulating at about 12% per week, while on the east coast, it reaches 30-35%.