Oncor seeks approval of Owl Hills-Tunstill POD 138-kV line in Texas

Oncor Electric Delivery Company on Aug. 31 filed with the Public Utility Commission of Texas an application for a certificate of convenience and necessity for the proposed Owl Hills-Tunstill POD 138-kV Transmission Line Project.

The new single-circuit line would be built on double-circuit-capable structures between the proposed Owl Hills substation in Culberson County, Texas, and the existing – under construction – Tunstill Point-of-Delivery (POD) station in Reeves County, Texas. The proposed Owl Hills substation would be located west of US 285 near the Culberson County/Reeves County line, the company added. The existing – under construction – Tunstill POD is located about four miles northeast of the community of Orla.

The company also noted that the project includes building half of the Owl Hills substation. The other half of the Owl Hills substation is being built in conjunction with the proposed Horseshoe Springs-Owl Hills 138-kV Line (Docket No. 48544), the company said, adding that that work may include dead-end structures, transformers, grading, fences, and other equipment.

The length of the line ranges between about 17.7 miles to 21.1 miles, depending on which route the commission selects, the company said.

The project area is situated across a geographic area that includes portions of Culberson, Loving, and Reeves counties in Texas, with no incorporated cities within or extending into the study area. The company also said that nearly the entirety of the study area consists of rural, undeveloped land used primarily for livestock grazing or oil and gas production.

Noting that it retained Halff Associates, Inc., to prepare the environmental assessment and routing study, Oncor said that it selected “Route 15” as the route that best addresses certain requirements.

According to the filing, of the 25 filed routes, Route 15 is about one mile longer than the shortest alternative routes (Routes 50 and 52) and estimated to cost about $20.6m, which is about $6.4m less than the most expensive alternative route (Route 37), and $92,000 more than the least expensive alternative route (Route 50).

The filing noted that:

  • Route 15 is about 18.7 miles long, which is about 2.4 miles shorter than the longest alternative route included in the application
  • No portion of Route 15 is located within the Red Bluff Reservoir’s flood plain
  • There are no habitable structures within the proposed right of way (ROW) of Route 15 nor within 300 feet of its centerline; there are no habitable structures within 300 feet of the centerline on any of the filed routes
  • Route 15 crosses no parks/recreational areas and does not have any parks/recreational areas within 1,000 feet of its centerline
  • Route 15 crosses no recorded cultural resource sites or have any cultural resources within 1,000 feet of its centerline

Discussing the project’s need, Oncor said in its application that the project was reviewed by stakeholders and endorsed by ERCOT’s Board of Directors as a Tier 1 transmission project as a sub-component of the Far West Texas Project 2. ERCOT performed power flow studies as part of the ERCOT Regional Planning Group (RPG) process and found voltage violations under NERC Standard TPL-001-4 reliability criteria. Oncor added that ERCOT recommended construction of a new 138-kV connection from the Horseshoe Springs to Owl Hills to Tunstill to Riverton stations to meet reliability needs. The Far West Texas Project 2 was approved by the ERCOT RPG and has received approval by the ERCOT Technical Advisory Committee (TAC) and the board.

Oncor also noted that its system in West Texas continues to experience load growth due to oil and natural gas production, mid-stream processing, and associated economic expansion in the area referred to as the Delaware Basin. In order to meet that need, a new transmission line is being proposed to connect Oncor’s Owl Hills substation to Oncor’s Tunstill POD station. That new line, in conjunction with the proposed Horseshoe Springs-Owl Hills line, would create a new 138-kV transmission circuit between the Horseshoe Springs switch station, located in Culberson County, to the Riverton switch station, located in Reeves County, Oncor added.

Culberson, Loving, and Reeves counties lie within the West Texas region of the Delaware Basin where deep underground shale deposits referred to as “plays” are providing opportunities for oil and natural gas exploration and production. Oncor also said that improvements in oil and natural gas exploration technologies have increased activity in the area and resulted in electric load growth at substations within the Delaware Basin. That growth has resulted in increased load served on the existing Oncor Wink-Culberson Switch 138-kV Line and the Oncor Yucca Drive Switch-Culberson Switch 138-kV Line, Oncor said.

The proposed project would address reliability concerns by being one of the elements that creates a new 138-kV pathway from the Horseshoe Springs switch station to the Riverton switch station. Oncor added that the Horseshoe Springs switch station is the future site for a dynamic reactive device (DRD), while the Riverton switch station is the site for a future 345-kV injection, both of which are referenced in the ERCOT-approved Far West Texas Project 2.

Oncor also noted that it and Targa Delaware LLC have signed an agreement for Oncor to provide electric service from Owl Hills. Targa is installing new oil and gas processing facilities in the area, Oncor said, adding that the customer’s projected maximum peak load demand at that facility is 54 MW. Load of that size in that remote location will require transmission level service, Oncor said.

According to the estimated schedule, engineering and design would begin in November and be completed in April 2019; ROW and land acquisition would begin in January 2019 and be completed in June 2019; material and equipment procurement would begin in February 2019 and be completed in June 2019; and construction of the facilities would begin in April 2019 and be completed in September 2019, which is also when the facilities would be energized.

About Corina Rivera-Linares 3058 Articles
Corina Rivera-Linares, chief editor for TransmissionHub, has covered the U.S. power industry for the past 15 years. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines. She can be reached at clinares@endeavorb2b.com.