Solar World: Desperately seeking silicon

By LEAH KRAUSS, UPI Energy Correspondent  |  Sept. 12, 2006 at 12:09 PM
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In a world of silicon scarcity, many solar energy companies are trying to find ways to stretch, cut back on, or even cut out the traditional photovoltaic panel's main ingredient.

Solar companies from around the world met in Dresden, Germany, this week at the 21st annual European Photovoltaic Solar Energy Conference and Exhibition, where several announced innovations that would allow panel makers to increase their production capacity.

Midland, Mich.-based silicon maker Dow Corning unveiled PV 1101 -- a feedstock material that can be blended with solar-grade silicon to stretch the dwindling supply.

"It is expected that polysilicon consumption by the solar industry will exceed that of the semiconductor industry for the first time this year or next. So, Dow Corning's PV 1101 will have a significant impact on the solar industry," a representative for the company wrote to United Press International in an e-mail.

"This is a major breakthrough, since PV 1101 is the first-ever industrial-scale silicon feedstock material derived from a metallurgical purification process specifically designed for the solar industry," and not for semiconductors.

The company said the polysilicon-PV 1101 blend is about as efficient as regular polysilicon-based photovoltaic cells, which convert sunlight into electricity with a chemical reaction.

Agreements with customers prevented the company from commenting on the price of blended solar cells, except to say that they are "cost effective, and the production of PV 1101 for the rest of this calendar year is spoken for by our customers."

Vista, Calif.-based Ferro Electronic Material Systems, meanwhile, worked to cut back on the amount of silicon each solar cell needs to operate, and announced a new, ultra-thin silicon wafer at the Dresden conference.

Ferro uses specialized aluminum backing on its solar cells, which the company said improves the electrical performance of the cell and thereby enables reducing the amount of silicon per wafer.

"The current-generation 'thin' wafers are 240 microns thick. Ferro's new aluminum product permits further silicon reductions to less than 180 microns thick ... (and boasts) equivalent or better electrical performance on multi-crystalline wafers," the company said in a statement.

A micron is one millionth of a meter; human hair ranges from about 40 microns to 120 microns thick, for comparison's sake.

Other companies, including Palo Alto, Calif.-based Nanosolar, are working on creating solar panels that don't use any silicon at all. A cocktail of copper, indium, gallium and diselenide -- CIGS for short -- can be used to create a solar "ink" to print on a variety of surfaces.

Though this technology won't be available on the market for a while, the promises are enticing: "(a) solar cell can simply be printed (or) solution-coated -- with unprecedented quality, yield, materials utilization, and amazing throughput," Nanosolar said.

Silicon scarcity is one of the major reasons detractors say solar energy costs too much. Worldwide demand for solar energy stands at 5 gigawatts, but silicon constraints mean the market can only supply just under half that amount, according to "The Gun Has Gone Off," a recent survey of the solar energy industry by analyst Michael Rogol.

"For 2006 ... there are roughly 13,000 to 15,000 tons of high-grade silicon available," Erik Thorsen, the president and chief executive officer of the Norwegian silicon supplier Renewable Energy Corporation, told UPI last week.

"Probably the demand (from solar companies) is twice the current supply," he said, just as Rogol assessed in his report.

Thorsen added that there is no immediate way to ramp up high-grade silicon purification, because "it takes two to three years to build a plant like that."

And although everyone is working to increase silicon and silicon-substitute production, no one is worried that solar supply will someday exceed demand.

"From the reports of the previous five years, the solar market has grown 40 percent annually. We expect the solar industry will continue to grow," Dow Corning's representative said.

Not only that, but "(silicon supply) could be a long-term problem because things like global warming and peak oil (prices) may force more PV use, and that would put silicon into a catch up mode even over the long-term," J. Peter Lynch, a financial consultant and an expert on the renewable energy industry, told UPI.


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