Arizona Electric Power Cooperative (AEPCO), in a March 31 motion, requested that the Arizona Corporation Commission (ACC) extend the time for AEPCO to build the Valencia 115-kV Transmission Line Tap and Optical Fiber Optic Ground Wire (OPGW) Installation Project, for which a certificate of environmental compatibility (CEC 152) was approved in an April 2010 decision.
“Condition No. 7” of CEC 152 gave AEPCO a seven-year term to build the projects, expiring on April 20, 2017, and allowed AEPCO to request to extend that time limitation prior to its expiration, the company noted. AEPCO said that its 2016 Ten Year Plan reports an estimated in-service of 2018 for the project. Consistent with Condition No. 7, AEPCO requested that the deadline to complete the Valencia project be extended for an additional five years to April 20, 2022.
The company also requested that the ACC amend the 2010 decision to delete two other projects from CEC 152 – the North Loop to Rattlesnake 115-kV Transmission Project and the Sandario 115-kV Transmission Line Tap Project.
AEPCO noted that the April 2010 decision, which was granted by the Arizona Power Plant and Transmission Line Siting Committee, authorized it to build:
- The North Loop to Rattlesnake project, which contemplated the construction of about 4.9 miles of new single circuit 115-kV transmission line to connect Tucson Electric Power’s (TEP) North Loop substation to the Western Area Power Administration’s (WAPA) Rattlesnake substation, and an equipment upgrade within the Rattlesnake substation to develop it into a four terminal switchyard
- The Sandario project, which envisioned the construction of about one mile of a new double-circuit 115-kV transmission line to connect the existing AEPCO Sandario substation to an existing Central Arizona Project (CAP) transmission line, and an equipment upgrade within the Sandario substation
- The Valencia project, which included the construction of about 2.7 miles of new single-circuit 115-kV transmission line to connect AEPCO’s existing Valencia substation to an existing CAP transmission line at the Spreader Tap, the addition of a switchyard to the Valencia substation, and the installation of a new fiber optic line, in conjunction with the CAP fiber optic network, to provide high speed communication to the future San Joaquin substation supplied by an existing CAP transmission line
The company noted that the North Loop to Rattlesnake project would have brought a new power source to the network from Arizona Public Service’s (APS) Saguaro substation to improve reliability and capacity, and the Sandario and Valencia lines would allow the CAP to tie into AEPCO’s network.
AEPCO said that the three joint projects were intended to support anticipated population and energy growth, as well as the associated need for new transmission capacity projected to occur in the service territories of AEPCO’s non-profit member cooperatives, particularly Trico Electric Power Cooperative. However, as has been true for many Arizona utilities, AEPCO’s member cooperatives have not experienced the population and energy growth that was projected to occur when CEC 152 was granted, the company said.
For that reason, only one of the projects, the Valencia project, is needed, and the in-service date for even that project has been delayed, AEPCO said. The Valencia project will strengthen the AEPCO and CAP electrical systems and remains an important component of AEPCO’s current transmission plan, AEPCO said.
Noting that the North Loop to Rattlesnake and Sandario projects are no longer needed, AEPCO said that it can meet the region’s needs with its planned Marana-Thornydale-Saguaro Interconnect, which relies in part on existing infrastructure. That project, when combined with the Valencia project, will provide sufficient support to meet AEPCO’s currently anticipated transmission capacity needs in the area, the company said.