The sun-baked deserts in the Middle East and North Africa region are prime candidates for solar energy projects (including the ambitious DESERTEC initiative), but who is going to dust off the windblown sand to keep solar panels operating at top efficiency? Self-cleaning photovoltaic (PV) systems are available, but they generally rely on water – a scarce commodity in these arid regions.
Researchers at Boston University are now proposing an innovative solution, based on electrodynamic screen (EDS) technology developed for NASA space missions.
At the national conference of the American Chemical Society held earlier this month, Professor Malay Mazumder reported that the EDS developed by his lab can remove 90% of dust particles from a square meter of PV paneling in two minutes while using just a small amount of electricity generated by the solar panel itself.
Who cares about a little dust?
“A dust layer of one-seventh of an ounce per square yard decreases solar power conversion by 40%,” Mazumder explains. “In Arizona, dust is deposited each month at about four times that amount. Deposition rates are even higher in the Middle East, Australia, and India.”
So, how does the self-cleaning EDS system work?
A transparent, electrically-sensitive material is deposited on the panels, or on a transparent plastic sheet covering the panels. When dust concentration (monitored by sensors) reaches a critical level, an electric charge is generated in the material, creating a dust-repelling wave that lifts and pushes away the dust.
“Our technology can be used in both small and large-scale PV systems,” Mazumder says. “To our knowledge, this is the only technology for automatic dust cleaning that does not require water or mechanical movement.”
Down to Earth
Mazumder and his colleagues initially developed the self-cleaning PV panel technology for use in lunar and Mars missions. “Mars, of course, is a dusty and dry environment, and solar panels powering rovers and future manned and robotic missions must not succumb to dust deposition. Neither should solar panels here on Earth.”
Mazumder also notes: “Less than 0.04% of global energy production is derived from solar panels, but if only 4% of the world’s deserts were dedicated to solar-power harvesting, our energy needs could be completely met worldwide. This self-cleaning technology can play an important role.”
Image via Phoenix Sun
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