An improved cleaning system has been developed that uses electrostatic force to remove sand from the surface of solar panels. A single-phase high voltage is applied to parallel wire electrodes embedded in the cover glass plate of a solar panel. It has been demonstrated that more than 90% of the adhering sand is repelled from the surface of the slightly inclined panel after the cleaning operation. The performance of the system was further improved by improving the electrode configuration and introducing natural wind on the surface of the panel, even when the deposition of sand on the panel is extremely high. The power consumption of this system is virtually zero. This technology is expected to increase the effective efficiency of mega solar power plants constructed in deserts at low latitudes.