San Luis Transmission Project

The proposed San Luis Transmission Project includes construction, operation, and maintenance of:

  • A single-circuit 500-kV transmission line, about 65 miles long, terminating at the existing, expanded, or new substations in the Tracy and/or Los Banos areas.
  • A 230-kV transmission line, about 3 miles long, connecting the San Luis Substation and the Los Banos Substation or new adjacent substation, and a 230-kV transmission line, about 20 miles long, connecting the San Luis Substation and the Dos Amigos Substation.
  • A single-circuit 70-kV transmission line, about 7 miles long connecting the San Luis and the O'Neill Substations.

Western also would upgrade or expand its existing substations, build new substations, or make the necessary arrangements to upgrade or expand existing PG&E substations to accommodate the interconnections of these new transmission lines.

The proposed project also would include the following facilities and improvements:

  • Right-of-way easements for the transmission lines with a typical width of about 125 to 175 feet for 230-kV lines and 200 to 250 feet for the 500-kV line.
  • Tubular or lattice steel structures used to support the transmission lines.  For the 230-kV line, structures typically would be between 100 and 200 feet tall depending on site-specific conditions.  A few taller structures may be required in some locations to address engineering constraints. 
  • Access roads, including improvements to existing roads, new overland access, and new unpaved temporary roads to access the proposed project facilities and work areas during construction and operation phases.
  • Ancillary facilities, such as communications facilities (e.g. overhead fiber optic ground wires, regeneration facilities) for access control and protection.

Why is SLTP needed? Western’s transmission contract with PG&E, under which power is transmitted over PG&E transmission lines between the San Luis Unit and Western’s transmission system, will end in Spring 2016. The San Luis Unit is a key component in delivering federal water to central valley municipalities, industrial, and irrigation users. The SLTP is intended to minimize expected power transmission cost increases to schedule federal power to the San Luis Unit and to provide long-term cost-based transmission service that will enhance operational flexibility and reliability for the Federal electric and water systems.