Solar panels are increasing in popularity across the U.S. as a sustainable source of power, but installations still tend to be most concentrated in sunny, warm climates. A light dusting of snow doesn’t affect solar panels very much because it blows away, according to the U.S. Department of Energy, but heavier snow accumulation prevents panels from absorbing sunlight to generate power.
A research team led by the University of Michigan developed a clear coating that reduces the amount of snow and ice accumulation on solar panels. Early tests indicate the coating helps panels generate 85% more energy than uncoated devices.
“Snow is a huge problem in northern climates,” said Anish Tuteja, U-M professor of materials science and engineering, in a news release.
“Solar panels might lose 80 or 90% of their generating capacity in the winter. So figuring out a way for them to continue generating energy throughout the year was an exciting challenge.”
The coating is primarily made of plastic — PVC or PDMS — and silicon or vegetable-based oils. It can be sprayed or brushed onto the panels. So far, it keeps snow and ice at bay for up to a year.
The U-M researchers previously developed other coatings to shed ice. However, the different densities of ice and snow have caused challenges with creating an all-in-one coating that handles both.
“Ice is relatively dense and heavy, and our previous coatings used its own weight against it,” Tuteja said. “But snow can be 10 times less dense than ice, so we weren’t at all certain that the tricks we use on ice would translate to snow.”
They worked to find the right balance of two properties behind ice-shedding coatings: surface adhesion strength — slipperiness — and interfacial toughness — the resistance to cracks along the junction of two materials. Interfacial toughness allows cracks to form between ice and a solar panel, thus freeing the ice. The two factors work differently on small and large surface areas.
The researchers worked with the University of Alaska to test the coatings on solar panels in Fairbanks. They applied the coatings to some panels at a solar field and monitored them for two weeks with automated cameras.
The tests in Alaska showed the coated panels averaged 28% snow and ice cover over an entire season, whereas the uncoated panels averaged 59% snow cover. Thus, the coated panels had more exposed surface area to absorb sunlight and could generate more power than the uncoated panels.
The current coating already can be used on solar panels. However, the team wants to continue tweaking it to develop a version that lasts for five years.
“Snow-phobic coatings, if we can demonstrate their long-term efficacy, will make solar power more reliable and more affordable in snowy regions, helping accelerate our nation’s transition to a more solar-dominated energy economy,” said Laurie Burnham, the project’s principal investigator.