Suntech Power, China’s largest solar panel manufacturer, plans to open its first American plant near Phoenix, the company announced on Monday. It would be the first time a Chinese solar company has built a manufacturing plant in the United States, experts said.

The plant will begin production in the third quarter of 2010 and will build panels from solar cells shipped from China. Those cells, in turn, contain substantial amounts of a substance called polysilicon manufactured at a factory in Texas.

Roger Efird, a managing director of Suntech, said in a telephone interview that shipping costs were an important factor in the decision to put a factory in the growing American market. Solar panels, with substantial amounts of glass and aluminum, are heavy, he said.

“As the price of solar panels has reduced dramatically in the last 12 months, the shipping costs have become a larger and larger portion of the overall cost of getting these projects to market,” Mr. Efird added.