U.S. trade officials opened investigations into imports of certain solar power products from China and Taiwan, a move that could have a major impact on the nation's fast-growing solar market. The investigations were sparked by a complaint at the end of last year by the U.S. unit of German solar manufacturer SolarWorld AG. The company at the time said it was seeking to close a loophole in a prior trade case that enabled Chinese solar panel producers to evade duties by using cells manufactured in other countries, mainly Taiwan. The U.S. Department of Commerce said it initiated antidumping duty and countervailing duty investigations, which will assess whether the products are being sold in the United States below their fair value, or if their manufacturers receive inappropriate levels of foreign government subsidies. The Commerce Department investigation and a parallel inquiry by the U.S. International Trade Commission (ITC) could open the door to expanding duties on some imported solar panels. In October 2012, the U.S. set steep duties on billions of dollars of solar products from China but turned down pleas to expand the scope of its order to include Chinese panels made with non-Chinese solar cells. In response, many Chinese module producers simply began sourcing cells from Taiwan. Jigar Shah, president of the Coalition for Affordable Solar Energy, a coalition of U.S. solar companies who have benefited from the low price of Chinese solar panels, said SolarWorld was "looking to single-handedly kill U.S. solar jobs." "Because of worldwide fair price competition, we have been able to significantly lower the cost of installing solar across the nation's residential and commercial rooftops - which, in turn, has created more than 119,000 jobs to date," he said. A SolarWorld spokesman, Ben Santarris, said trade aggression by China has decimated the solar industry in the United States and other countries. He pointed to Thursday's announcement by Japan's Sharp Corp that it would stop making solar panels at its Tennessee plant by the end of March. The ITC is scheduled to make a preliminary ruling on whether there is a reasonable indication that imports from China or Taiwan materially injure, or threaten to injure, the local industry by February 14. A negative finding would stop the investigations. If the ITC determines that the imports could be hurting the domestic industry, the Commerce department is scheduled to make preliminary determinations about subsidies in March and dumping in June. The ITC must make a final decision before any duties are applied. (Reuters)