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Is cheaper solar power near?

Citizen Staff Writer



A demonstration Wednesday that used the sun’s energy to quickly cut a nickel-sized hole in a steel plate could someday translate into cheap, abundant electricity.

UA professor Roger Angel has developed a way to make low-cost mirrors with a high quality of focus for photovoltaic systems that are five times less expensive than reflective PV devices now in use.

The technology is the first step in developing a photovoltaic system that could compete in price with conventional natural gas power plants, said Angel, University of Arizona Regents’ professor in astronomy and director of the Steward Observatory Mirror Lab.

Plans call for using the reflectors to concentrate the sun’s energy on photovoltaic cells that produce electricity, resulting in higher production levels than from conventional PV systems.

He said when the technology is mature, such solar plants could come in at less than $1 a watt.

The current price for developing photovoltaic arrays is $6 to $7 a watt, said Joe Salkowski, Tucson Electric Power Co. spokesman.

“To be able to develop PV capacity at $1 a watt would be a noteworthy accomplishment. The cost would be comparable to a natural gas-fired power plant,” Salkowski said.

“And we would have to buy fuel for that (natural gas) power plant. With the sun, the fuel is free,” he said. “We’re pulling for him. It would be a very attractive source of power for us and our customers.”

Angel’s demonstration occurred in the old swimming pool behind Bear Down Gym on the University of Arizona campus. A 10-foot diameter glass reflector with a silver-coated back burned a hole through a one-quarter inch thick steel plate in about 15 seconds.

The sun’s focused energy quickly heated the steel to 2,700 degrees Fahrenheit, said Angel, who wore a sturdy oven mitt to remove the pierced object – after it cooled down a bit.

The photovoltaic design application will be different than Wednesday’s demonstration, he said, and will operate at much lower temperatures that will not harm – or burn holes through – PV cells.

The reflective material Angel developed will allow production of low-cost mirrors that are “good enough” for solar applications but not appropriate for telescope applications where the mirrors cost 10,000 times more, he said.

Angel declined to discuss the technique developed to produce the mirror glass, citing patent and intellectual property issues.

Making lots of reflector-grade glass rapidly and inexpensively is the first step in turning around the solar industry, said Richard C. Powell, co-director of the Science Foundation Arizona Solar Technology Institute.

Designing steel structures that will keep the reflective materials focused on PV cells, even in high winds, is the next step, Powell said.

And designing the optics to better concentrate the sun’s energy on PV cells under all conditions is in the works, he said.

The technology lends itself to large-scale solar projects, Powell said, but will require less space than conventional PV arrays.

The project is funded by a $1 million federal budget earmark as well as money from the U.S. Department of Energy and Science Foundation Arizona, said U.S. Rep. Gabrielle Giffords, D-Ariz., who attended the demonstration.

“What we have seen is the the beginning of an innovative way to produce electricity,” Giffords said. “This is the future.”

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