Associated Press: Solar manufacturer First Solar Inc. said Wednesday it will build the largest photovoltaic power plant in the U.S. near an existing facility in Nevada. Tempe, Ariz.-based First Solar said the 48-megawatt plant will produce power for roughly 30,000 homes. It will be added to the existing 10-megawatt El Dorado plant run by Sempra Generation in Boulder City, Nev., about 40 miles southeast of Las Vegas. John Carrington, First Solar’s executive vice president for marketing and …