The figures don’t lie: solar energy is on the rise. According to the International Energy Agency’s 2021 report, power generated by renewable solar power systems increased by 23% globally between 2019 and 2020. Solar power generated 3% of all electricity generated in the United States in 2020. This figure is expected to increase by a whopping 20% by 2050.
However, there is a problem that threatens the sustainability of solar energy: dust. When dust, pollen, or other particles accumulate and settle on the surface of a solar panel, this is referred to as photovoltaic soiling (or PV soiling). According to the National Renewable Energy Laboratory in the United States, this layer of grime reduces the light-harvesting ability and efficiency of a solar panel, resulting in energy losses ranging from 7% in some parts of the United States to 50% in the Middle East.
While many solar power plants address PV soiling by washing panels with water, the effort consumes approximately 10 billion gallons of water per year—roughly enough water for 2 million people. In a future of impending water scarcity, reducing this massive water footprint while minimizing energy loss is critical.
Fortunately, scientists have developed an H2O-free method of cleaning a dirty solar panel. In a study published on Friday in the journal Science Advances, researchers at MIT developed a system that removes dust by utilizing a startlingly simple phenomenon that surrounds you every day: static electricity. An electrode passed over a solar panel charges the dust particles on the panel’s surface. Another electrode on the glass cover of the panel sends an electric charge to the panel’s surface. This interaction bounces the dust off the panel in an instant, using no finite resources and causing no physical damage to the solar panels themselves.
“We can recover up to 95 percent of a solar panel’s power output using this technique,” Sreedath Panat, an MIT doctoral student and study’s lead author, told The Daily Beast.
This technique works primarily because 80 percent of dust particles contain silica, an insulating material that acquires an electrical charge as a result of absorbing moisture from the surrounding environment. Panat explained that as long as there is enough humidity in the air (above 20 to 30 percent), there is enough moisture for the silica to absorb. Fortunately, in dry areas like the desert, too little moisture isn’t as much of a problem because humidity tends to fluctuate where it’s highest at night. Panat explained that the solar panel’s repulsion system can be programmed to activate during periods of optimal humidity in those regions.
The researchers intend to motorize their system, which will not require as much energy as it may appear. Panat and his team are considering allowing the motor to draw a small amount of power from the solar panel or even adding a dedicated mini-solar panel to supply the required juice.
While it is difficult to predict when this waterless solar panel cleaning system will be available—Panat said his team recently submitted a pending patent—he is confident in the prototype’s scalability and future for upcoming field tests.
“We are really hoping to conduct some field studies by making a large-scale system, installing it on a larger solar panel, and measuring output,” he said, adding that what his team has demonstrated is a proof-of-product “that can be easily scaled and that already works.”
As the popularity of solar panels grows, using the cleansing power of electricity rather than water may become part of the solar power system package in the near future.