From an engineering perspective, the routes proposed by Tucson Electric Power (TEP) for its proposed Irvington to Kino 138-kV Transmission Line Project appear to be technically sound, Elijah Abinah, Director, Utilities Division, said in a June 5 filing made with the Arizona Power Plant and Transmission Line Siting Committee.
“Staff believes that the proposed project will improve the reliability, resilience, and safety of the grid as well as the delivery of power in Arizona,” Abinah said.
As noted in the filing, TEP has filed an application for the issuance of certificates of environmental compatibility (CEC) for the project, which consists of new lines and structures totaling about 3.63 miles to 4.64 miles, depending on the route selected, to connect the existing Irvington substation to the future Kino substation.
Approval to site the Kino substation has been issued by the City of Tucson, Abinah added, noting that the project would cross private and Pima County owned land, as well as the City of Tucson and Pima County road rights of way (ROWs). TEP is requesting a 300-foot corridor for the preferred route to allow for siting flexibility.
Abinah added that the line would be built using tubular steel monopole structures, typically 75 feet to 110 feet above ground; taller structures may be required for site specific clearance issues.
The proposed line would run from the Irvington substation, located at East Irvington Road and South Alvernon Way, to the future Kino substation, to be located at South Kino Parkway and East 36th Street in Tucson, Ariz., Abinah said.
According to TEP’s application, “Alternative A (Blue line) (Preferred)” is an approximately 4.64-mile route that uses existing road ROW along Irvington Road, Benson Highway, Park Avenue, and 36th Street. That alternative would extend west along Irvington Road from TEP’s Irvington Campus to Benson Highway, and would turn northwest, continuing along Park Avenue to 36th Street, where it would then turn east to the future Kino substation at the southeast corner of Kino Parkway and 36th Street.
Alternative A has a total cost of about $5.1m, according to the application.
Abinah said in the June 5 filing that according to TEP, the proposed project would provide increased capacity to serve anticipated future load increases, reduce the load on part of the aging existing 46-kV system serving the area, and provide increased reliability under contingency conditions. According to TEP, the existing 46-kV and 138-kV systems do not provide sufficient capacity to serve the new developing load, which includes a large mixed-use development in the vicinity of 36th Street and Kino Boulevard.
The project has been included in TEP Ten-Year Plans as a planned high-voltage transmission project – under different names in previous Ten-Year Plans and under this name in the most recent Ten-Year Plan – since 2011, Abinah added. As such, the project has been included in all area transmission studies, including the Seventh, Eighth, and Ninth Biennial Transmission Assessments (BTAs), and all studies performed under the auspices of the Southwest Area Transmission Group and WestConnect, Abinah said.
The project was included in the studies required to support the last three BTAs, as well as the one currently in progress, Abinah said. Power flow, facility loading limit, single contingency outage, extreme contingency, and transient stability studies were conducted for the interconnected Arizona system, Abinah said, adding that the results show no negative impacts on grid reliability and safety, provided they are constructed in compliance with, and operated in accordance with, good utility practice and applicable reliability standards.
Abinah said that the Utilities Division recommends inclusion, as a condition to any CEC that the siting committee may issue, of the standard cathodic study condition to evaluate the risk to any existing natural gas or hazardous liquid pipelines that notes that when project facilities are located parallel to, and within 100 feet of, any existing natural gas or hazardous liquid pipeline, TEP is to:
* Ensure grounding and cathodic protection measurements are performed to show that the project’s location parallel to, and within 100 feet of, such pipeline results in no material adverse impacts to the pipeline or to public safety when both the pipeline and the project are in operation. TEP is to take appropriate steps to ensure that any material adverse impacts are mitigated. TEP is to provide to the commission staff, and file with Docket Control, a copy of the measurements performed and additional mitigation, if any, that was implemented as part of its annual compliance-certification letter
* Ensure that measurements are taken during an outage simulation of the project that may be caused by the collocation of the project parallel to, and within 100 feet of, the existing natural gas or hazardous liquid pipeline. The measurements should either show that such simulated outage does not result in customer outages, or include operating plans to minimize any resulting customer outages. TEP is to provide a copy of the measurements results to the commission staff, and file it with Docket Control, as part of its annual compliance-certification letter
As noted in a June 8 filing that TEP submitted to the committee, a public hearing regarding the project was scheduled to be held before the committee on June 12.
Article amended at 5:11 p.m., EST, on July 12, 2018, to reflect in the headline that Arizona regulatory staff call for approval of the project.