Self-Cleaning Solar Panels: More from NASA’s Lab

Commercial solar cells with dust shields in NASA lab (Photo by Dr. Carlos Calle)

Following up on Monday’s story on self-cleaning solar panels, I contacted Dr. Carlos Calle, senior research scientist at NASA’s Electrostatics and Surface Physics Laboratory at the Kennedy Space Center, where the work originated. Calle was lead author of a fascinating 2009 technical article ($) on adapting the extra-terrestrial dust removal technology for solar panels here on Earth (and on the moon which has extremely fine dust particles).

The technology uses strategically placed electrodes to generate a electromagnetic wave that first lifts sunlight-blocking dust particles off the surface of the solar panel and then carries them away from the panel.

NASA's Dr. Carlos Calle

Calle’s lab made a variety dust shields, some rigid and opaque, some flexible and transparent. These were placed on top of off-the-shelf solar panels squares measuring two inches on each side. The test square were then covered with fine dust particles (roughly the size of the width of a human hair). In the journal article, Calle reports that “the transparent dust shields applied to commercial solar panels operate successfully under high vacuum even under extreme dust loading conditions that caused the solar cell performance to drop to 11-23%” of its normal output.

In fact, only the dustiest test cell (11% of normal performance) failed to reach 98.4% of normal output after the dust shield was activated. One panel (20.3% of normal) regained 99.4% of its electrical output after the dust curtain was energized.

I asked Calle if he thought water would still be needed to augment the dust shields. He was confident that the technology would “eliminate the need for water cleaning of solar panels.”

At this stage, Calle isn’t ready to speculate on how much the dust shields will add to the cost of a PV panel. However, given the simplicity of the design, the fact that so little power is needed to remove nearly all the dust, and the money saved by not using water in a desert, the dust shields will likely be attractive to manufactures, rooftop installers and utilities building large-scale solar PV projects in the desert.

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