First Solar Inc (FSLR.O) (FSLR.O) will build two new manufacturing plants in the United States and Vietnam to meet strong demand for its thin-film photovoltaic modules. Booming demand for clean electricity systems has sent sales for many of the leading solar companies soaring this year, with First Solar, Suntech Power Holdings (STP.N) and Yingli Green Energy Holding Co (YGE.N) reporting they had sold out of products. The First Solar plants, which will add 500 megawatts of module production, will lift the company to the industry’s top spot in output capacity with 2.7 gigawatts (2,700 megawatts) in 2012. Earlier this month, China’s Suntech opened its first manufacturing plant in the United States as part of its plan to raise output capacity this year to 1.8 gigawatts. First Solar’s current capacity is about 1.4 gigawatts. One gigawatt is about the size of a nuclear power reactor. Unlike other major solar companies, First Solar, the largest in the sector with market value of $11.7 billion, produces modules that use cadmium telluride to produce electricity from sunlight rather than polysilicon. First Solar has previously announced it would expand production in Malaysia, Germany and France to help supply its pipeline of more than 2 gigawatts of projects. The plants would put new manufacturing capacity close to strong demand growth areas, company spokesman Alan Bernheimer said. Earlier this year the company completed an expansion of its Perrysburg, Ohio, manufacturing plant, which serves as First Solar’s primary hub for engineering, research and development. The announcement pushed shares in First Solar up 4.1 percent to $142.55 in afternoon trade on the New York Stock Exchange. It also lifted shares in its supplier 5N Plus (VNP.TO) to a 14-month high at C$6.44 on the Toronto Stock Exchange earlier on Thursday.-Reuters