The Public Utility Commission of Texas, in a May 11 order, approved, as amended, Oncor Electric Delivery Company’s July 2017 application to amend its certificate of convenience and necessity (CCN) in order to build a new double-circuit-capable, 345-kV transmission line, with one circuit initially installed and operated at 138 kV.
As noted in the order, the Riverton-to-Sand Lake transmission line in Loving, Reeves, and Ward counties extends from Oncor’s Riverton switching station currently under construction in Reeves County, located along County Road 440, just east of U.S. Highway 285, to Oncor’s proposed Sand Lake switching station, to be located about six miles northeast of the City of Pecos on the northwest side of Farm-to-Market Road 3398 in Ward County.
The commission noted that the line is needed to, for instance, address reliability violations; serve load growth driven primarily by increased oil- and gas-related activity; extend transmission service to an area without it; improve the level of the voltage entering new substations; and improve substation transformer- and distribution-feeder performance at existing substations.
The area is currently served by Oncor’s Wink-to-Culberson and Yucca Drive-to-Culberson 138-kV transmission lines, the commission said, adding that the aggregate historical load on those lines, the Culberson Loop, increased from 29 MW in 2012, to 205 MW in 2016. At the time of the application, the aggregate load was estimated to exceed 400 MW in 2018, and exceed 500 MW in 2019, the commission noted.
By the time Oncor filed direct testimony, those estimated loads had increased to 677 MW for 2018, and 839 MW by 2022, the commission said, adding that Oncor’s estimates only reflected load increases it confirmed based on signed customer agreements.
The ERCOT regional planning group endorsed the transmission line as a Tier 2 transmission project, the commission said. ERCOT also recommended building the line at 345-kV standards to meet long-term load growth in the area and support voltage conditions, the commission noted.
The line will serve load growth by establishing transmission service for new substations in the project area, including Oncor’s Mentone SW substation, and by improving distribution feeder performance for existing customers, the commission said. Approval of the line on “route 54” will allow Oncor to establish the new Mentone SW substation, as recommended by ERCOT, near the community of Mentone, without the need to file an additional CCN application to build an additional transmission line to connect the Mentone SW substation to this line, the commission said.
Construction of the line at 345-kV standards will provide synergies with the upcoming Far West Texas group of projects that the ERCOT Board of Directors recently endorsed, as well as others being studied; allow for future operation of the line at 345 kV; and support future 345-kV transmission system improvements in the area, the commission said.
The approximately 38.78-mile Route 54 is estimated to cost about $49.9m, excluding station costs, the commission said, adding that about $8.8m in station costs associated with the facilities at the Riverton switching station and Sand Lake switching station are included in the transmission line. Including those costs, route 54 is estimated to cost about $58.6m, the commission noted.
Route 54 does not cross any parks or recreational areas, the commission said. Also, no adverse effects to archaeological or historical resources are anticipated as a result of the construction of the line, the commission said, adding that there is one recorded cultural resource site crossed by route 54, and two such sites located within 1,000 feet of the route.
The commission noted that route 54 will not cross any known habitat for endangered or threatened species, and that construction of the line on that route will not significantly affect existing land uses or geological, hydrological, or wetland resources of the area.
Among other things, the commission said that Oncor is to conduct surveys to identify pipelines that could be affected by the transmission line, if not already completed, and coordinate with pipeline owners in modeling and analyzing potential hazards because of alternating-current interference affecting pipelines being paralleled.
Also, the commission said that Oncor is to use best management practices to minimize the potential impact to migratory birds and threatened or endangered species.