Construction Update: Underground Milestones, Imperial Valley Progress and More

SDG&E is making steady construction gains on the Sunrise Powerlink during the summer of 2011.  The Sunrise Powerlink team and its contractors are currently in the field working on various aspects of the new transmission line and have reached several important milestones.

 

Significant progress continues to be made on 6.2-mile underground segment of the Sunrise Powerlink in the community of Alpine.  SDG&E has completed the installation of 36 of 40 concrete vaults that will be set during the project, or 90 percent.  Of the remaining vaults, only two need to be set along Alpine Boulevard and two on private property.  These final vault installations are expected to be completed in the third quarter of 2011, which will help alleviate some traffic impacts to Alpine Boulevard.

 

The next step in the underground process, trenching and installing underground cable, is also in full swing. Crews have completed 24 of 42 conduit segments, which will house the underground cable.  SDG&E has pulled 15 of 42 cable segments and spliced three of these segments together.  SDG&E also has started working on street improvements for Alpine Boulevard that were approved by San Diego County, including curbs, gutters and rubberized asphalt. 

Another underground initiative, the jack and bore process being used to install the 230 kV line underneath Interstate 8 and a creek that crosses Alpine Boulevard, is about three-quarters complete. Both tunnels under Interstate 8 and one of two tunnels under the creek near downtown Alpine have been completed.

 

Overhead Construction Moves into the Imperial Valley: Dozens of Towers Completed

SDG&E has made progress on overhead construction, including the completion of 44 steel lattice towers and the installation of more than 90 tower foundations.  The majority of this overhead construction activity is occurring in the Imperial Valley desert, where dozens of towers were recently completed near Plaster City.

Towers and foundations also have been completed in the Jacumba/Boulevard area; and several foundations have been installed near Campo and Scripps Ranch.  More than 50 percent of the project’s 421 total steel lattice towers are being installed using air-crane helicopters. 

 

Numerous project support sites and construction yards have been completed or are under development. Of the project's 19 construction yards, 15 are now completed and in full operation.  Many tower sections are currently being assembled in construction yards ready for transportation and installation at sites along the project route.

SDG&E is aiming to complete the Sunrise Powerlink in the second half of 2012.  The new transmission line will bolster reliability, access vast sources of renewable energy and boost the local economy.