Without divestitures, NRG would have difficulty pursuing its plan to double output at the South Texas Project, the state's largest nuclear plant, by 2,700 megawatts by 2016. Crane said they would need to sell somewhere between 3,000 megawatts and 5,000 megawatts of generation in the state. NRG shares closed up 36 cents to $42.51, while Calpine added 8 cents to $21.28, both on the New York Stock Exchange. Calpine rose 3.4 percent to $22 in light trading after the market closed.