PG&E close to finishing $36m transmission upgrade

Pacific Gas and Electric (PG&E) has begun the final phase of a project to upgrade a transmission line from Atascadero, Calif., to San Luis Obispo.

“The focus of the Atascadero-[San Luis Obispo] 70-kV reconductoring project is to help PG&E continue reliably meeting electricity demand in the region and lessen environmental-caused degradation on equipment from the salty air, fires,” and other factors, a PG&E spokesperson told TransmissionHub May 13.

Work on the first phase of the project began in 2011. More than simply a reconductoring project, it included installing new transmission tower foundations and tower bases along an existing eight-mile stretch of line from the top of Cuesta Grade, the steepest grade along California’s Highway 101, to PG&E’s San Luis Obispo Substation, the spokesperson said.

The first phase of the upgrade also included replacing about 60% of the line’s wooden poles – more than 130 poles – with light duty steel poles that are not susceptible to fire and replacing 41 out of 45 existing steel transmission towers.

The final phase, which began in early May, includes installing new conductor along the entire 16-mile stretch from Atascadero substation to the San Luis Obispo substation. The new conductor will be 715.5 Kcmil AA (all aluminum) conductor, which is less expensive and weighs less than the copper conductor being replaced.

During the final phase, the utility will use helicopters to transport the new towers and crew members to the various locations along the Cuesta Grade where ground crews will complete the installations, the spokesperson said.

Project construction is expected to be finished later this year at an estimated cost of $36m.

The equipment being replaced dates to the 1930s. The replacement equipment could last into the next century, the spokesperson said.

PG&E is a subsidiary of PG&E Corporation (NYSE:PCG).