CORRECTED-Trina sees 20 pct silicon cost drop in 2009

(Corrects spelling of name of executive, percentage of sales to Germany)

NEW YORK, Sept 24 (Reuters) - Trina Solar Ltd (TSL.N) expects its silicon costs to drop by as much as 20 percent in 2009, while the average selling price of its solar modules will fall by a more modest 5 to 6 percent, an executive said on Wednesday.

That decline in silicon costs versus the more modest selling price decline would lead to a "a significant margin expansion," Arturo Herrero, Trina's vice president of sales and marketing, told Reuters in an interview.

Trina, which earlier on Wednesday announced the largest single rooftop solar project in the United States, expects 30 percent of its sales would be to Germany, compared with about 35 percent in 2008, Herrera said. (Reporting by Matt Daily, editing by Gerald E. McCormick)