Closeup of Solar Panels with Dirt (IMAGE) University of California - San Diego Caption For a typical residential solar system of 5 kilowatts, washing panels halfway through the summer would translate into a mere $20 gain in electricity production until the summer drought ends -- in about 2.5 months. Credit Jacobs School of Engineering/UC San Diego Usage Restrictions Please credit Jacobs School of Engineering/UC San Diego License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.