SCE completes removal of transmission towers through city of Chino Hills, Calif.

Southern California Edison (SCE) has completed the removal of the 16 towers for the portion of the Tehachapi Renewable Transmission Project (TRTP) that will extend through the city of Chino Hills, Calif. (Docket No. 07-06-031).

“All the towers are down!” a Chino Hills spokesperson told TransmissionHub in an e-mail Nov. 8.

The towers, which reached heights of 200 feet, were erected in 2011 along SCE’s existing 150-foot right-of-way (ROW) as specified when the project was originally approved by the California Public Utilities Commission (CPUC) in 2009.  However, SCE was ordered in November 2011 to halt work on the overhead portion of the line after community residents complained to the CPUC that the towers’ “visual, societal, and economic impact … has been far more significant than what the city or the commission envisioned.” The CPUC then ordered SCE to prepare alternatives to the existing design and route.

On July 11, the CPUC reversed its original decision and ordered the 3.5-mile stretch of Segment 8A that will extend through Chino Hills placed underground and the existing towers removed. Although removal of the towers, which began in late September, is now complete, SCE will only be able to perform limited additional tasks related to the undergrounding, including ordering long lead time materials and real property acquisitions, until its request to modify a portion of the July order is resolved.

In a petition for modification filed Sept. 9, SCE asked the CPUC for permission to install voltage control equipment along the underground portion of the line because the highest rated cross-linked polyethylene (XLPE) cable available that can be used in the 500-kV application is rated at 550 kV. In addition, SCE noted that undergrounding the transmission line will cause an increase in the transmission line charging current that could, in some cases, cause the voltage on the system to exceed its 550-kV rating.

The utility stated that studying the possibility of changing the basic insulation level (BIL) rating for the line, as directed by the CPUC in its July order, would significantly delay the in-service date of the TRTP, perhaps as late as 2019.

There is no specific time frame for the commission to respond to the petition. However, responses to petitions for modifications must be filed within 30 days of the date that the petition was filed. Further, if granted permission by the administrative law judge, SCE may reply to responses to its petition for modification.

When completed, the 250-mile, $2.5bn, 500-kV project will be capable of moving up to 4,500 MW of renewable energy from wind and solar installations in the state’s renewable-rich Tehachapi area to the load pockets of the Los Angeles basin.

SCE has called the project “a critically important, high-voltage transmission line, the timely completion of which is essential for California’s progress toward its aggressive renewable energy goals.”

SCE is a subsidiary of Edison International (NYSE:EIX).