Desert solar panels may be kept dust-free with static electricity. 

Solar panels' production is substantially reduced by dust, however by introducing an electric field to the panels, dust particles reject each other and disperse.

Desert solar panels might be cleaned using static electricity, saving 45 billion litres of water every year.  The Mohammed bin Rashid Al Maktoum Solar Park in the United Arab Emirates and the Desert Sunlight Solar Farm in California are two of the world's largest solar farms. These are often dusty conditions, with particles rapidly collecting on solar panels. A month's worth of dust may reduce the output of a solar panel by 40%.

  Spraying significant volumes of distilled water over the solar panels is one of the most frequent strategies to remove this dust. The procedure is pricey and unsustainable, according to Kripa Varanasi of the Massachusetts Institute of Technology, because it uses an estimated 45 billion litres of water every year only to clean solar panels. Join us for a mind-blowing celebration of experiences and ideas. From March 12 to 14, 2022, New Scientist Live is going hybrid, with a live in-person event in Manchester, UK, that you can also watch from the comfort of your own home.

“That amount could provide water for over a million people [every year],” he says.   

Varanasi and his colleagues developed a water-free method of cleaning solar panels using static electricity in the lab to assist alleviate this problem.  Ordinarily, dust does not carry electricity. When moisture in the air binds to the surface of a dust particle — a process known as adsorption – this changes. Solar panels are also protected by thin glass sheets that aren't conductors. Varanasi's team changed this by applying a 5-nanometer coating of transparent zinc oxide and aluminum on the surface of a solar panel.  After that, a metallic plate was floated over the dust-covered panel, and a 12 kilovolt electric field was applied between the plate and the panel. Both layers become electrodes, or conductors that make contact with a non-metallic component of a circuit, as a result of this.

The metal plate became negatively charged, while the solar panel and dust became positively charged. Dust particles began to resist each other as the plate moved above the panel, forcing them to disperse.  The dust particles absorbed enough moisture from the solar panel in the laboratory at roughly 30% relative humidity to entirely remove it, recovering 95% of its lost power output. According to Varanasi, even the harshest deserts have a relative humidity of approximately 30%.  "I believe that water is a valuable commodity that is undervalued," he argues. "I'm hoping that this would encourage more people to consider water concerns."

source:  Science Advances, DOI: 10.1126/sciadv.abm0078