Work is under way on planned transmission line

After nearly two years of planning, Utah's largest electric utility announced Tuesday that crews had begun constructing a $600 million, 135-mile high-voltage transmission line from a new substation near Downey, Idaho, to an existing substation near the Salt Lake City International Airport.

Rocky Mountain Power spokesman David Eskelsen told the Deseret News that work on the Populus to Terminal transmission line is under way, with the first segment in PacifiCorp's Energy Gateway transmission expansion scheduled for completion in 2010.

Work on the project began at the end-points in Salt Lake City and Downey last month, he said.

Eskelsen said that upon completion, PacifiCorp's Energy Gateway transmission expansion would help to ensure that its two divisions, Rocky Mountain Power and Pacific Power, could serve the long-term electric needs of their customers.

"There haven't been any really large additions to the transmission system since the 1980s," Eskelsen said. The development of a new transmission corridor to the mountain west region will address the critical need for additional electricity capacity, he said.

Currently, Rocky Mountain Power serves just under 1 million customers in Utah, Wyoming and Idaho, according to the utility Web site. Pacific Power serves over 600,000 customers in Oregon, Washington and California.

In 2007, Rocky Mountain Power announced that it would build more than 1,200 miles of high-voltage transmission lines to carry electricity from Wyoming to Utah, Idaho, Oregon and parts of the Southwest. The $4 billion project involves two 500-kilowatt lines with construction beginning this year and completion planned for 2014, Eskelsen said.

The cost of the lines would be passed on to customers in power rates sometime between 2014 and 2016, the company said.

Eskelsen said that the early stages of construction will include building access roads and excavation for concrete foundations to support the transmission structures. As the year progresses, nearly 350 contract employees will work along the line route to complete the project, a press release stated.

The Populus to Terminal segment consists of two sub-projects — Populus to Ben Lomond, which would consist of a transmission line stretching 90 miles from the Populus substation near Downey, Idaho, to the existing Ben Lomond substation in Box Elder County. The Ben Lomond to Terminal segment would add a transmission line alongside existing high voltage lines from the Ben Lomond substation to the Terminal substation, near the Salt Lake City airport — 46 miles away.

In addition, another segment of the line would be built across Idaho into Oregon. The 600-mile line would have the capacity to deliver up to 3,000 megawatts of electricity from Wyoming to Idaho into Utah and up to 2,500 megawatts of new capacity from Idaho west into Oregon.

A megawatt is enough electricity to power approximately 500 typical homes, Eskelsen said.

The second major line would run from the Jim Bridger power plant near Rock Springs, Wyo., into central Utah to the Mona substation located in Juab County, the company said. That line would have the capacity to deliver up to 3,000 megawatts from Wyoming to Mona, and 3,000 megawatts from the Mona area into the desert Southwest.

E-MAIL: jlee@desnews.com