SoCal Edison supports recommended decision modifying Tehachapi project

The developer of the Tehachapi Renewable Transmission Project (TRTP) has offered its qualified support of a recommended decision that would grant it permission to make technical changes to the portion of the project ordered to be placed underground through the city of Chino Hills, Calif. (Docket No. A07-06-031).

In comments filed with the California Public Utilities Commission (CPUC) on Jan. 2, project developer Southern California Edison (SCE) said it supports the recommended decision by administrative law judge (ALJ) Jean Vieth, that would have California regulators amend their July 11 decision and change some of the technical provisions of its order.

In the July 11 decision, which ordered the undergrounding of a 3.5-mile stretch of the project that passes through the city of Chino Hills, the CPUC denied SCE a request that the company be allowed to include voltage control equipment on the 500-kV line. Instead, the CPUC directed the utility to study the possibility of changing the basic insulation level (BIL) rating for the line.

The utility countered that the provisions of the order would be problematic, as the highest-rated cross-linked polyethylene (XLPE) cable available that can be used in the 500-kV application is rated at 550-kV, allowing only a 10% deviation from the intended operating voltage.

SCE further 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. Therefore, the company said, voltage control is necessary to control voltage and prevent damage.

In addition, 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 to as late as 2019.

The proposed decision approves SCE’s request to remove the basic insulation level study requirement and authorizes the utility to include voltage control equipment for reactive compensation as part of the construction of Segment 8A.

It also increases the reasonable maximum cost for Segments 4 through 11 of the project by $23m, which a previous decision identified as the approximate cost based on SCE’s preliminary engineering.

In its comments, SCE took issue with the proposed decision’s handling of the cost issue, noting that the cost of the modified voltage control design was not yet known. While the utility had sought to have the CPUC “defer all findings concerning the costs of components of the project and consider the issue in a consolidated process when the overall project cost estimates were addressed,” it noted that it would not seek changes to the proposed decision “in the interest of minimizing risk of further delay [and] given that the issue is not binding since transmission costs are ultimately recovered at FERC.”

The proposed decision, issued Dec. 12, was subject to a 30-day public comment period before it could be placed on the agenda for a voting meeting. It is on the agenda for the CPUC’s meeting on Jan. 16.

When completed, the project will be able to deliver up to 4,500 MW of largely renewable energy to Southern California, enough electricity to power three million homes, the utility said.

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.”

California’s renewable portfolio standard calls for 33% renewable energy by 2020.

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