The proposed TRTP would extend from eastern Kern County to the city of Ontario in San Bernardino County. In all but a few areas, the project would be constructed in existing utility rights-of-way (ROW), replacing or upgrading existing SCE facilities. In the areas where new ROWs are needed, SCE would need to acquire a ROW ranging between 100 feet and 300 feet wide. One new substation and upgrades at existing substations are also proposed.
The accompanying maps on this website and the local inserts provide a visual representation of the project. Also, the section of this website entitled Path of Electricity may help explain some of the terms and ideas discussed here.
The TRTP consists of the following elements, which include Segments 4 through 11 (Segments 1, 2, and 3 were addressed in previous, separate proceedings, as explained below):
The TRTP consists of these elements:
Segment 4 - Construction of the new Whirlwind Substation in Kern County west of Rosamond. This 500/220 kV substation would be connected to the proposed Cottonwind Substation1 by a new four-mile double-circuit, 220 kilovolt (kV) transmission line and to SCE’s existing Antelope Substation in west Lancaster by a new 14- mile 500 kV transmission line. Construction would be in a new ROW, parallel to the existing ROW.
Segment 5 - Construction of a new 18- mile-long 500 kV transmission line that would connect SCE’s existing Antelope Substation with SCE’s existing Vincent Substation near Acton. This new line would be built next to an identical existing 500 kV ine and would replace two 220 kV lines that would be removed. An existing ROW would be utilized. This new line would be initially energized at 220 kV.
Segment 6 - Replacement of approximately 27 miles of an existing 220 kV transmission line that runs from SCE’s existing Vincent Substation to the southern edge of the Angeles National Forest (ANF) near the city of Duarte with a new 500 kV transmission line that would initially be energized at 220 kV. An existing ROW would be utilized. Replacement of approximately five miles of an existing SCE 220 kV transmission line between Vincent Substation and the northern border of the ANF with a new 500 kV transmission line.
Segment 7 - Replacement of 15 miles of the existing 220 kV line from the ANF border near the city of Duarte south to SCE’s existing Rio Hondo Substation in the city of Irwindale and then continuing southwest across various San Gabriel Valley cities toward SCE’s existing Mesa Substation in the Monterey Park/Montebello area with a double-circuit, 500 kV transmission line. Existing ROWs would be utilized and various lower-voltage subtransmission lines between the Rio Hondo and Mesa Substations would require relocation within existing ROW or public ROW.
Segment 8 - Replacement of existing single-circuit, 220 kV line that runs from the existing Mesa Substation area to the Chino Substation area and existing doublecircuit, 220 kV line from Chino Substation to the existing Mira Loma Substation with a 32-mile double-circuit, 500 kV line. Replacement of approximately seven miles of existing 220 kV line that run from SCE’s Chino Substation to its Mira Loma Substation located in the city of Ontario with a double-circuit, 220 kV line. Existing ROWs would be utilized except for where approximately three miles of new ROW would be required in limited areas. Various lower-voltage sub-transmission lines in the Chino area would require relocation within existing ROW or public ROW.
Segment 9 - Installation of equipment and upgrades at Antelope, Vincent, Windhub and Whirlwind Substations to connect new 220 kV and 500 kV transmission lines and to help maintain proper voltage levels.
Segment 10 - Construction of a new 12- mile, single-circuit, 500kV line to connect the proposed Whirlwind Substation (Segment 4) with the Windhub2 collector substation. New ROW would be required.
Segment 11 - Replacement of approximately 20 miles of 220 kV transmission line between the existing Vincent Substation and Gould Substation near La Cañada Flintridge with a new, 20-mile, single-circuit, 500 kV transmission line. Installation of a second 220 kV transmission line on the currently empty side of the transmission towers that already extend from the area of Gould Substation across various San Gabriel Valley cities to the area of Mesa Substation in Monterey Park. An existing ROW would be utilized.
1 - Cottonwind Substation is currently undergoing environmental review by the County of Kern in conjunction with a proposed wind farm development under an existing application.
2 - Substation One (Windhub) was included in SCE’s proposed Antelope Transmission Project Segment 2-3 application (A.04-12-008) submitted to the California Public Utilities Commission for approval in December 2004 and amended September 30, 2005.
