Plans for new SDG&E transmission line reach
a milestone with the results of a comparison study
San Diego Gas & Electric (SDG&E) has chosen an eastern connection for its proposed, new 500-kilovolt (kV) transmission line that will improve grid reliability, reduce energy costs and provide access to renewable energy sources.
While no specific route has been identified at this point, the line, if approved, would tie into SDG&E’s current power grid through an eastern connection from the utility’s Imperial Valley substation to an as-yet-undetermined point in the middle of SDG&E’s service territory or load center.
Broad-based review
Over the past six months, a subcommittee of the Southwest Transmission Expansion Study (STEP) group, made up of a cross-section of community, regulatory and market stakeholders, evaluated 18 different potential interconnections based on criteria that included reliability, access to renewable resources, timing, and cost and economic benefits. No specific routes were considered.
“The selection of a preferred direction for this transmission line is a milestone in our effort to build this vital link to our region’s electricity network,” says David Geier, SDG&E’s vice president of Electric Transmission and Distribution.
“The STEP Technical Working Group reviewed the technical merits of each of the possible alternatives in an open, collaborative, stakeholder process and narrowed the options to four that provide the greatest benefits to the region," he adds. "SDG&E identified the eastern connection as the most feasible in terms of cost, timing and benefits to customers, including access to renewables and the ability to get it in service by 2010.”
ISO support
“There’s no question that the addition of a major interconnection in Southern California will help ease the transmission congestion that continues to pose economic problems for the region,” says Armie Perez, chairman of the STEP group and the director of grid planning for the California Independent System Operator (Cal-ISO). “We are pleased to be part of the STEP process, and we look forward to the next steps for this project.”
The next phase of the process to license this new major transmission line is to begin the specific routing studies and preparations for the needed regulatory filings. The California Public Utilities Commission (CPUC) must approve the project to allow construction of the new line.
“We have completed a key technical step toward building a new line for our region that will bring with it multiple benefits for customers,” says Geier. “Next, we must continue to work proactively with the communities we serve in a collaborative process to gather feedback to ensure we arrive at the best solution for our region’s energy future.”
More about the STEP process
STEP’s Technical Working Group consists of 22 stakeholder members and 13 separate entities, such as state agencies, regulators and market participants, including utilities from California, Arizona and Mexico, along with independent consultants and generators.
Besides the Cal-ISO, the group includes: the California Energy Commission, the Comision Federal de Electricidad in Baja California, Southern California Edison, the Imperial Irrigation District and Arizona Public Service.
In October 2004, SDG&E first presented nine possible interconnections for study, which grew to 18 choices, based on the feedback from the Technical Working Group.
On April 27, 2005, SDG&E presented the results of the technical studies and economic analysis of the options to the full STEP group.
The utility will submit a final report of the findings to the group by the end of this month.
