Deposition of a transparent, electrically sensitive materialon glass or a transparent plastic film eliminates about 90 percent of dust,dramatically boosting efficiency of solar panels.

In a report at the National Meeting of the American ChemicalSociety (ACS), scientists describe how a self-cleaning coating on the surfaceof solar cells could increase the efficiency of producing electricity fromsunlight and reduce maintenance costs.

Sensors monitor dust levels on the surface of the panel andenergize the material when dust concentration reaches a critical level. Theelectric charge sends energy over the surface of the material, moving dust offof the panel's edges.

"We think ourself-cleaning panels used in areas of high dust and particulate pollutant concentrationswill highly benefit the systems' solar energy output," says study leader MalayK. Mazumder. "Our technology can be used in both small- and large-scalephotovoltaic systems. To our knowledge, this is the only technology forautomatic dust cleaning that doesn't require water or mechanical movement."

Electrodynamic screens (EDS) are composed a series ofparallel electrodes on a substrate that is energized by a three-phasehigh-voltage amplifier. One potential weakness is the requirement of anexternal power source, but that can be overcome if the EDS can derive powerfrom the solar panel.

Use of solar, or photovoltaic, panels increased by 50percent from 2003 to 2008, and forecasters predict 25 percent annually.Large-scale solar installations already exist in the U.S., Spain, Germany, theMiddle East, Australia and India.

As a general rule, they are located in dry areas where windssweep dust into the air and deposit it onto the surface of solar panels. Thedust reduces the amount of light that can enter the business part of the solarpanel, decreasing the amount of electricity produced. Cleaning the panels isdifficult because of scarcity of water.

"A dust layer of one-seventh of an ounce per square yarddecreases solar power conversion by 40 percent," Mazumder says. "In Arizona,dust is deposited each month at about four times that amount. Deposition ratesare even higher in the Middle East, Australia and India."

Mazumder initially developed the self-cleaning solar paneltechnology for use in NASA's lunar and Mars missions. "Mars of course is adusty and dry environment," Mazumder says, "and solar panels powering roversand future manned and robotic missions must not succumb to dust deposition. Butneither should the solar panels here on Earth."

The current market size for solar panels is about $24billion, according to Mazumder. "Less than 0.04 percent of global energyproduction is derived from solar panels, but if only four percent of theworld's deserts were dedicated to solar power harvesting, our energy needscould be completely met worldwide. This self-cleaning technology can play animportant role."

Mazumder was part of a team at the Dept. of Applied Science,Dept. of Systems Engineering at the University of Arkansas at Little Rock thatworked on the project. They were awarded a patentfor their work in 2005.