San Marcos to Escondido Transmission Line Project (TL 6975)
Project Questions and Answers
SDG&E is proposing a reliability project that would include a combination of new overhead single-circuit electric power line structures, rebuild of existing structures from single circuit to double circuit, and the reconductoring and re-energizing of existing conductors on existing poles and towers. The majority of the project would occur within existing rights-of-way (ROW)s.
The proposed project includes the construction of a new 69kV transmission line and upgrade of existing facilities between the existing San Marcos and Escondido substations which will provide greater capacity for electricity to flow to the Escondido and San Marcos communities.
If approved, the proposed project would be located in the communities of Escondido, San Marcos, Carlsbad, Vista and the County of San Diego. The project includes three main segments:
Segment 1 Rebuild: rebuild approximately 1.8 miles of existing 69kV overhead transmission line to the west of the San Marcos Substation.
Segment 2 New Build: addition of approximately 2.8 miles of a new single circuit 69kV overhead transmission line from the end of Segment 1 to Meadowlark Junction (San Elijo Road between Elfin Forest and Fallsview Roads).
Segment 3 Replace/Re-energize: Replace conductor on approximately 7.4 miles of power lines from Meadowlark Junction to the existing Escondido Substation on existing poles and towers. Replaced transmission line will then be energized.
As our region expands, our demand for energy also grows. Given the load growth over the past decade in the communities of San Marcos and Escondido, increased demand for energy has created congestion on the existing power lines creating strain on the electric system. The proposed project will add more capacity to accommodate the increased demand for power in this area, resulting in greater reliability.
In addition to balancing demand daily, SDG&E is also committed to planning for additional demand years ahead. To accommodate the recent growth and planned future development in the northern part of the county, we’ve determined that additional resources are necessary to be able to meet the demand on the electric system. The increased demand over the past few years has put extra strain on two power lines that deliver power to the Escondido and San Marcos communities. The proposed project, which has been reviewed and approved by the state’s controller of the electric grid (CAISO), would alleviate these loading violations and improve reliability and improve system efficiency in SDG&E’s service area.
When designing a project, SDG&E considers many options as part of the evaluation, including cost impacts to all ratepayers, potential short-term and long-term impacts to the environment, impacts to private property and utilization of existing electric rights-of-way. The proposed project route was chosen as it was the best nexus between utilizing existing easements and rights-of-ways, limited environmental impacts, and cost effectiveness.
An underground route was considered as one of the alternatives in SDG&E’s application to its regulator, The California Public Utilities Commission, but was not chosen as the preferred route by SDG&E because all ratepayers would bear the burden of the increased costs associated with underground construction.
When designing a project, SDG&E considers many options as part of the evaluation, including cost impacts to all ratepayers, potential short-term and long-term impacts to the environment, impacts to private property and utilization of existing electric utility rights-of-way. Underground lines were considered by SDG&E as one of the alternatives in the application to the California Public Utilities Commission, but SDG&E did not select the underground route based the fact that all ratepayers would bear the burden of the costs. Ultimately, it’s up to the CPUC to approve the proposed project and determine the project route.