Environmental degradation of the optical surface of PV modules and solar mirrors by soiling and high RH and mitigation methods for minimizing energy yield losses

Utility-sale solar plants are mostly installed in semi-arid and desert lands and are subjected to high dust deposition rate. Dust layer build up on solar collectors causes major energy-yield loss. Maintaining designed plant capacities requires more than 90% efficiency of light transmission or specular reflection for PV modules and CSP mirrors, respectively. The combinations of high relative humidity (RH), high surface temperature, and long residence time of the dust on the optical surface degrades the solar collectors over time. A tenacious mud like coating is formed, which strongly adheres to the PV modules and concentrating mirrors and requires scrub cleaning. If the global solar-power output is to increase from current GW levels to the TW level, as is envisioned, the water cleaning process would result in an unsustainable demand for water. This paper provide a brief review of the application of an emerging technology of transparent electrodynamic screen (EDS) for removing dust, as frequently as needed, from the solar collectors without water. Power output efficiency is maintained greater than 90% compared to that of the panel under clean conditions. Dust removal efficiency (DRE) is more than 90% with test dust samples obtained from different arid zones and energy consumption for EDS operation is less than 0.03 Wh/m2/cleaning cycle. The method is water-free and provides easy retrofitting onto existing panels and has a high potential for a cost-effective large-scale roll-to-roll production, commercial application, and a significant reduction of operation and maintenance costs.