Friday, October 17, 2008

SD Solar Conference Draws a Record 22,500

Second in a two-part series

As invariably happens in San Diego when it hosts a world-class event, the weather was clear and warm for Solar Power International 2008 which ended yesterday. While the Stock Market had its second crazy week of mostly Dow Jones downers, the solar industry showed renewed vibrance as 22,500 visitors from over 70 countries attended the nation's premier solar conference, 10,000 more than last year's event in Long Beach.

Governor Arnold Schwarzenegger made an appearance despite the a deepening California budget shortfall and the nationwide financial malaise.

"Of course we are now facing tough economic times, but that's why we need to focus on solar and [the environment]," he said. "We should not listen to those who say [that] should take a back seat. That's just plain wrong."

Always looking for an excuse to come to San Diego, the governator continued.

"Let me tell you, in San Diego 80 percent of the people voted for me in the recall," Schwarzenegger said, referring to the election in 2003 in which Californians voted to recall his predecessor, Gray Davis, and to replace him with the actor. "The other 20 percent never forgave me for my movie, "Hercules in New York," which is completely understandable."

Sharp Solar announced offering a new thin-film panel beginning next August. Thin-film PV invariably is cheaper to produce than crystalline modules and less expensive on the market. However, the sales rep from Japan I spoke with said Sharp's thin-film entry will be priced about the same per watt as its popular average-grade (13.7%) silicon panel until volume production reaches its peak.

DH Solar of Prairie du Chien, Wisconsin, had an outside exhibit showing a 16-panel array on the company's Horizon-to-Horizon Sun Tracking System. It's the first sizable tracking device this reporter's seen that can be used at home or for small business with some extra space for the ground-mounted system. Advantages of tracking are as much as 40% higher output than fixed mount; the system need not go on a roof, maintaining architectural aesthetics; and the system can be placed to avoid any shading issues. For more information go to

Finally, of particular interest to me was what appeared to be an ultra-shiney sausage that was six feet long and seven inches in diameter. In fact it was a pure-silicon ingot or "boule" (see picture) that would be cut into ultra-thin wafers for use as photovoltaic cells or semiconductor chips for computers, watches or other electronics applications.

The normal process of "growing" a silicon ingot is interesting. A seed crystal on a rod is dipped into a crucible of molten silicon and spins it into a cylinder similar to spinning cotton candy around a paper cone. As the seed is extracted from the crucible the silicon solidifies and eventually a large, circular boule is produced. A semiconductor crystal boule is normally cut with a diamond saw into circular wafers (like cutting salami) and each wafer is polished for the fabrication of semiconductor devices or photovoltaic cells. Ingot production takes about 1.5 days and cutting/polishing the wafer chips takes eight days. Finding high-quality silica (sand) plus the long, somewhat complex process keeps crystal silicon panels costly which is why more thin-film combinations are being tested and marketed.

Solar Power International 2009 will be held at the San Jose Convention Center next October 19-22.


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