Researchers at the Massachusetts Institute of Technology have developed a method for cleaning solar panels that could potentially save billions of gallons of water.
“The water footprint of the solar industry is mind-boggling,” said MIT Professor of mechanical engineering Kripa Varanasi. “So, the industry has to be very careful and thoughtful about how to make this a sustainable solution.”
By using electrostatic repulsion to remove dust from solar panels instead of water, the industry could save 10 billion gallons of water each year, the researchers said.
The MIT research team developed a lab-scale prototype for the dust removal process and demonstrated up to 95% recovery of lost power output.
Lab tests conducted showed that the dropoff of energy output from the panels happens steeply at the very beginning of the process of dust accumulation and can reach a 30% reduction after one month without cleaning. Even a 1% reduction in power for a 150 MW solar installation could result in a $200,000 loss in annual revenue. The researchers said that globally, a 3-4% drop in power output from solar plants would amount to a loss of between $3.3 billion and $5.5 billion.
The novel cleaning process works by passing an electrode over the panel and applying an electrical charge to the panel itself. The operation can be conducted remotely.
The MIT team cited previous research that found 1 to 5 million gallons of water is used to clean each 100 MW of solar capacity as evidence that the industry needs to change how it cleans panels.
Lab tests determined that the process works best in humidity greater than 30%.