LS Power also proposes to build the White Pine Energy Station, one of three Nevada coal-fired power projects that have attracted opposition from environmental groups.

While the transmission line would carry power from the White Pine power plant to Las Vegas, LS Power and its affiliate want to build the power line even if the coal plant is not built, said Mark Milburn, director of project development at LS Power.

The Southwest Intertie Project, as the 500-kilovolt line is called, would enable Nevada Power Co. of Las Vegas to tap power from geothermal energy sites in Northern Nevada, Milburn said. Sierra Pacific Power Co. of Reno could utilize power from concentrating solar power plants in Southern Nevada, he added.

Sierra Pacific Resources, holding company for Nevada Power and Sierra Pacific Power, has been proposing a north-south transmission line as part of the project to build a coal-fired power plant at Ely. The line then would carry power generated by the Ely Energy Center to customers in Nevada and Reno.

Sierra Pacific Resources also has said that its transmission line would enable it to carry renewable energy, such as wind, solar and geothermal power, to Las Vegas, but it earlier argued it needed the coal power plant to make the north-south line financially feasible.

In a conference call with analysts on July 25, however, Chief Executive Officer Michael Yackira clarified the company's position.

"If Ely were delayed further, we certainly would consider separating that and pursuing a transmission line, but that's too early to tell," Yackira said.

Charles Benjamin, president of Nevadans for Clean Affordable Energy, said his coalition of nine groups favors development of a north-south transmission line as long as the transmission line is not part of a coal power project. Benjamin said the north-south line would enable Nevada to develop its geothermal, solar and wind power resources for use in Nevada and for export to other states.

LS Power still needs to obtain BLM approval of a construction, operation and maintenance plan for the southern segment of SWIP.