CARMEL MOUNTAIN —— San Diego Gas & Electric officials unveiled a wide, triple-headed "corridor" Monday inside of which they hope to build a new "energy superhighway" —— a 120-mile string of high-power lines from Imperial Valley into North County.

A few dozen planning advisors, environmentalists and city officials attended SDG&E's turnout Monday and warily eyed the pathways the utility hopes to use to build the first major power transmission lines into the county in two decades. The project also includes an 80-acre power station.

SDG&E officials are scheduled to hold a second meeting from 5:30 to 8:30 p.m. today at Ramona Elementary School, one of several communities where the power lines and station could be located.

The proposed line would stretch from the Imperial Valley substation northwest through the desert to a new substation in North County, and then southwest to SDG&E's Penasquitos substation in Rancho Penasquitos.

SDG&E managers said they are hoping to head off some of the eventual "not in my backyard" protests that could arise over the project by including the public and local officials in the planning process.

They said they plan to announce a specific route by early 2006, after holding a series of public meetings late next month.

Pending approval by the state Public Utilities Commission, which would also hold public hearings, SDG&E plans to have electricity flowing through the power lines by 2010.

SDG&E says the cost of the project would depend on several factors, including how much land they would have to buy and the topography along the path.

Jim Avery, SDG&E senior vice president, said Monday that San Diego County desperately needs the new power-line system, dubbed the "Sunrise Powerlink." He said county power demand is growing while its reliable supply is shrinking.

He said the fossil fuel and nuclear power plants that have sustained the county —— Carlsbad's Encina Power Plant, Chula Vista's South Bay Power Plant and the San Onofre Nuclear Generating System —— are growing older, producing higher-costing electricity than new power stations, and are too expensive to upgrade.

And, he said, state contracts that import more than half the electricity that county residents use annually are scheduled to end by 2011.

Power officials are building new plants locally, such as the Palomar Energy Plant under construction in Escondido. But Avery said building new plants cannot supply all the energy the county needs.

Meanwhile, the potential Sunrise Powerlink would bring clean, cheap, "renewable" electricity —— created by geothermal steam, wind and solar power. The state has mandated that all power companies create at least 20 percent of their power through renewable sources by 2017.

Avery said SDG&E now produces about 5.5 percent of its energy through renewable sources.

The assembled planners, environmentalists and city officials, meanwhile, got their first look Monday at the potential paths the new power lines could travel.

The lines themselves could tower 160 feet high and 200 feet wide for the main 500 kilovolt lines that will run from Imperial Valley to the new substation, and up to 130 feet high and 100 feet wide through North County to Rancho Penasquitos.

The potential pathways, which are still miles wide in many points, run in a pitchfork array from Imperial Valley, skirting huge portions of Anza Borrego State Park and connecting into one larger unit just east of Julian.

The connected swath stretches southwest through Ramona, Santa Ysabel and Poway —— just south of Highway 67 —— into Mira Mesa and Rancho Penasquitos. Along its path, the swath stretches just south of Escondido into Poway, missing Lake Hodges and Fairbanks Ranch, before detouring west just south of Del Mar.

Several audience members worried aloud about aesthetics, and asked if SDG&E could bury power lines in the earth rather than stretching them on towers.

Avery said the 500 kilovolt lines could not be buried. The smaller lines that would stretch inside the county could be buried —— but only at five to 10 times the cost, a price that communities and ratepayers statewide would have to bear.

Jim Lyon, associate planner for the city of Poway, said his city was "concerned" that SDG&E could locate the substation or run its massive lines through their community.

"It's a huge 'NIMBY' (Not in My Back Yard) issue for us, too," he said.

Lyon commended SDG&E for trying to get public input on the project, but said there eventually would be some public backlash.

"It's going to be a battle when they get down to the preferred alignment," Lyon said, "to negotiate with those various communities who'll say, 'OK, how bad is it going to be? Where is it going to go? How is it going to affect my community? What is it going to cost?' That's where the negotiations come in."

Contact staff writer Gig Conaughton at (760) 739) 6696 or gconaughton@nctimes.com.