Power Operations &Planning

P.O. Box 53933MS 3259  PHOENIX, ARIZONA 85072-3933

Telephone: (602) 250-1649

FAX: (602) 371-6022

E-Mail Address:

March 08, 2012

Mr. David Franklin

Chair, WECC Technical Studies Subcommittee

Southern California Edison

1 Innovation Way

Pomona, CA 91768

Mr. Enoch Davies

WECC Technical Staff

155 North 400 West

Salt Lake City, UT 84103-1114

Subject: APS’ 2012 WECC Annual Progress Report

In accordance with the reporting guidelines established by the WECC Planning Coordination Committee, progress on the following significant additions and changes to the Arizona Public Service company's system for the 2012-2021 periods are being reported.

Palo Verde – Delaney 500kV line.

The project will increase the export/scheduling capability from the Palo Verde area to provide access to both solar and gas resources. This is a joint participation project with APS as the project manager. The initial plan of service for the project will be a 500kV line betweenthe Palo Verde Switchyard and the new Delaney Switchyard. This line is approximately 15 miles. The expected in service date is 2013.

Delaney – Sun Valley 500kV line.

The project will include development of a new Sun Valley switching station in the north of Phoenix, in the area of the CAP's Hassayampa Pumping Station and a 500kV transmission line approximately 35 miles long connecting the new site with the Delaney 500kVhigh voltage yard. It also consists of the 500/230kV transformer with associated 230kV station at Sun Valley. This new line will be needed to serve projected need for electric energy in the Northwest part of the Phoenix metropolitan area. It will also increase the import capability to the Phoenix metropolitan area as well as increase the export capability from the Palo Verde area. The Arizona Corporation Commission (ACC)approved APS’ preferred route for this new line. It is anticipated the line will be a joint participation project with APS, SRP, and the Central Arizona Project(CAP) with APS as the project manager. The expected in service date is 2015.

Sun Valley –Morgan500kV line.

Thisproject will add scheduling capability between the Palo VerdeHub and the Southern Navajo system nearWestwing. This project consists of approximately 40 miles of 500kV line from the Sun Valley substation to the existingMorgan 500 kV switching station near the existing 230kV Raceway station. It is anticipated the line will be a joint participation project with APS, SRP and CAP with APS as the project manager. The expected in service date is 2016. TheMorganswitching station was formerly known as the TS9 switchyard.

Palo Verde (or vicinity)–North Gila 500kV

This project will provide transmission capacity and import capability into the Yuma area required tosupplement limited transmission and generation resources in the Yuma area. This project consists of approximately111 miles of single-circuit 500kVline from the Palo Verde (orvicinity)switching station to the existing North Gila 500kVsubstation and will include a 500/230kV transformer at North Gila. It is anticipated the line will be a joint participation project. The expected in service date is 2015.

Additional plans of APS include:

Various 230kV system additions that are designed to increase load serving capability voltage supportand enhance reliability of the APS's transmission system performance. These projects will be reported to WECC in thedocument entitled “Summary of Significant Transmission Additions and Changes". The reported systemfacility additions will not have a significant impact upon the WECC bulk interconnectedtransmissionsystem performance and, therefore, a Progress Report will not be made.

Other APS 230kV Transmission Projects:

  • Sundance – Pinal Central 230kV line (in service 2014)
  • Sun Valley – Trilby Wash 230 kV line (in service 2015)
  • North Gila –TS8 230kV line (in service 2015)
  • Palm Valley – TS2 – Trilby Wash 230kV line (in service 2015)

If you have any comments or questions about any of the above projects, please contact me or Barrie Kokanos.

Sincerely,

Peter Krzykos

Transmission Planning Section Leader

Arizona Public Service Company

602-250-1649

Contact Person

Barrie Kokanos, PhD, PE

Arizona Public Service Company

P.O. Box 53933, MS 3259

Phoenix, AZ 85072-3933

Tel; 602-250-1370

FAX: 602-371-6022

E-Mail:

cc:B. Smith

B. McMinn