The system doesn't use much energy--electrical current is small and typically it only needs to be on between two and five minutes a day, Mazumder says. The system could include a sensor to determine when the panel needed cleaning. The technology doesn't work if the dust gets wet and muddy, so it should be triggered to remove dust before it rains, Mazumder says.

Mazumder's technology is one of two approaches NASA has funded for cleaning off solar panels. The other vibrates the entire panel to shake dust loose. It's still not clear which will prove more practical for space missions, says Surampudi, who oversaw the research into both dust-clearing techniques. Using vibrations is simpler and requires fewer modifications to the solar panel, he says. But it does not remove fine particles as well as the electrical field approach. For terrestrial applications, Mazumder's technology will have to compete with other potential approaches to cleaning off solar cells without using water, such as blowing air on them or adding a nonstick layer.

The electrical field technology could prove simple to produce, Mazumder says, because many solar manufacturers already have equipment for depositing transparent electrodes, which would generate the electrical fields, onto panels. He says the next step is to determine whether it will be possible to meet the researchers' goal of keeping manufacturing costs below about 1 percent of the total cost of the solar panel. But the value of the system will depend on how dusty solar panels get in different locations. Conventional washing with water, for example, works well enough for a large collection of rooftop solar panel systems operated by Southern California Edison, the utility says.