Scientists Studying Solar Try Solving a Dusty Problem – NREL

Scientists Studying Solar Try Solving a Dusty Problem – NREL

Many Ways Considered To Ease Soiling. Limited information is available on soiling by location, including on a map produced by NREL.. “One of the biggest things we’re trying to do to help now is we’re trying to gather data and put it on a map,” Muller said.

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The layer of dust and pollen that settles on the windshield of your car is easily removed with a turn of the lever that activates wipers and water. Removing that layer from a solar panel—especially one inconveniently located from any source of moisture—requires considerably more work.

The accumulation of dust, soot, or other particulates causes a drop in the efficiency of photovoltaic (PV) panels, which translates to a decline in the amount of power produced and lost income for their operators. But cleaning these solar panels carries a cost as well.

Ongoing research at the National Renewable Energy Laboratory (NREL) into the problem of PV “soiling” continues to work toward possible solutions, including patented technology to address the problem and providing a map of where soiling poses the biggest issues.

Soiling a Problem from the Start

Since solar power first became widely accepted decades ago, scientists have toiled to improve the efficiency of PV panels and to bring down the cost of producing electricity from the sun. Those were the big tasks. Now, with solar providing an increasing percentage of the nation’s power needs at a low cost, researchers have turned to secondary problems with the technology.

“We made it,” said Matthew Muller, an engineer at NREL who specializes in the reliability and performance of PV. “Solar’s getting deployed, but we’re losing energy because solar’s getting deployed in dusty locations.”

The energy lost annually from soiling amounts to as much as 7% in parts of the United States to as high as 50% in the Middle East.

Rain and wind can be enough to scour some dust from PV panels, said Lin Simpson, who served with Muller as the co-principal investigator at NREL for a $6 million Department of Energy-funded research effort into soiling from 2016 to 2019. However, because PV panels cool down at night and attract morning dew, the dust can go through a process called cementation. The soiling is literally cemented onto the panel.

“Depending on what area you’re in, you can have different minerals that are deposited as dust on the surfaces,” said Simpson, a senior scientist. “Once it goes through the cementation process, it can become much more difficult to remove to where even a strong rain won’t remove it.”

A one-time cleaning for a 10-megawatt solar farm—which provides enough electricity to power 2,000 homes for a day—can cost an estimated $5,000. Simpson said in some areas, such as California’s Central Valley where “soiling rates get sufficiently high and the rain sufficiently low,” it makes economic sense to clean the panels more than once a year.

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