Technology designed to help space exploration can be used to keep solar panels dust free and energy efficient, say US researchers.
Dr Malay K. Mazumder, of Boston University has presented his latest findings at the national meeting of theAmerican Chemical Society during August this year.
The use of photovoltaic cells as a eco friendly safe way to makeelectricity has increased by 50% in recent years and some forecasts suggest an annual growth rate of at least 25% into the future, says Mazumder.
Large-scale solar installations already exist in Australia, the United States, Europe, the Middle East and India.
Mazumder says such installations are often built in sun-soaked desert areas where dry weather and winds deposit dust on the solar panel surfaces.
“A dust layer of 4 grams per square metre decreases solar power conversion by 40%,” he says.
“In Arizona, dust is deposited each month at over 4 times that amount. Deposition rates are even higher in Australia, the Middle East, and India.”
Using space technology to battle dust
Mazumder helped develop self-cleaning technology to keep solar panels clear of dust during NASA missions to the Moon, and for the Mars rovers.
He now thinks this technology could help solve the dust problem here on Earth too.
The technology involves coating the solar panel surface with electrodes of Indium tin oxide, a transparent, electrically-sensitive material.
Sensors monitor dust levels on the surface of the panel and energise the material when dust concentration reaches a critical level.
When energised by three-phase, 500 to 900-volt pulses at 5 to 20-hertz, the electrodes produce a cascading wave of electrostatic and dielectrophoretic forces that repel dust particles.
Mazumder says the process removes about 90% of dust in 2 minutes and uses only a small amount of the electricity generated by the panel for cleaning operations.
Claims questioned
However Professor Martin Green from the University of New South Wales ARC Photovoltaics Centre in Sydney, questions some of the claims.
“Dust build-up is not as a big a problem in practice as the story makes out. Normally, no cleaning of a solar panel is required,” says Green.
“In designing a solar system, it’s normally de-rated by 5% to accommodate the average level of dust coating.”
“It would be interesting if it could be done for less than 5% of the plant’s total energy production.”
Green says he’s never seen a 40% drop in power output as claimed, by Mazumder although he did once see a 14% cut due to dust.
“Even in desert areas rain and wind usually clear dust away,” he says.
Green says photovoltaic performance could be increased by up to 20% simply by improving the structures now built into the silicon material.
“In fact performance could in future be doubled through new concepts now being investigated in the laboratory.”
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