Nearly two years after Southern California Edison (SCE) asked California regulators for permission to add aviation safety markers to a portion of the Tehachapi Renewable Transmission Project (TRTP) that will pass close to the Chino Airport, an administrative law judge (ALJ) on Oct. 14 issued a proposed decision approving the utility’s unopposed request (Docket No. A07-06-031).
The proposed decision responds to a petition for modification that SCE filed on Oct. 17, 2011, asking the California Public Utilities Commission (CPUC) for permission to change the project’s design to implement mitigation measures recommended by the Federal Aviation Administration (FAA). Specifically, SCE sought permission to install marker balls on some wire spans, aviation lights on some transmission towers and reduce the heights of several structures near the Chino Airport.
“The FAA recommended those design changes to increase aviation safety by making hazardous structures (wire spans and transmission towers) more visible to pilots,” ALJ Jean Vieth said in her proposed decision.
In its review of the request, the CPUC determined that the nature of the proposed changes required additional environmental review, and ordered the preparation of a supplemental environmental impact report (SEIR). Under the California Environmental Quality Act (CEQA), a supplement review must be given the same kind of notice and public review as the final EIR. The draft SEIR was prepared, released for public comment on April 11, 2013, and a final SEIR was released Oct. 3.
In the SEIR, the CPUC found that the additional structures “would contribute to the long-term loss and degradation of scenic highway viewsheds and the national scenic trail viewshed … and visual impacts would be significant and unavoidable.” However, the final SEIR noted that the marker balls and lights “increase public safety by making hazardous structures (transmission structures and wire spans) more visible to pilots,” according to the proposed decision.
The final SEIR concluded that the additional safety markers would not result in new impacts, nor would they substantially increase the severity of impacts identified in the final EIR, in the areas of air quality, biological resources, noise, or traffic and transportation.
Proposed decisions by the CPUC must usually be made available for public review and comment at least 30 days before being voted on by the commission. However, because this matter was uncontested, it can be voted on as early as the commission’s next voting meeting on Oct. 31, a CPUC spokesperson told TransmissionHub Oct. 21.
Another petition for modification by SCE remains pending, the proposed decision noted.
On Sept. 9, SCE filed a petition for modification of the commission’s July 11 decision approving the placement of the 3.5-mile Segment 8A underground. In that ruling, the CPUC directed that the utility study the possibility of changing the basic insulation level (BIL) rating for the line rather than approving voltage control equipment, as SCE had requested. In its September petition for modification, the utility said that portion 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.
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, it said, voltage control was 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 as late as 2019.
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).