Saudi Arabia is the land of Solar Farms, The dust storm environment make the solar farms to get the dusty sand deposits over the panels. This dust deposits affects the efficiency of solar panels to the tune of 0.4 to 0.8% during normal day and upto 60% after the sand storm.
Recently an automated system named “NOMAAD” NO-water Mechanical Automated Dusting Device (NOMADD) a robot which cleanse the surface of the panes and improve the performance.
NOMAAD is mounted over the top of the panels and it operated daily twice to clean the surface effectively, A single NOMADD can clean a row of panels about 600 feet long.
More details about NOMAAD can be read here:
Similar such robots were designed by Japanese and Israelite.