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 Horseshoe Springs Switch-Owl Hills Substation 138-kV Transmission Line Project.
The new single-circuit line would be built on double-circuit-capable structures between the proposed Horseshoe Springs switch station and the proposed Owl Hills substation in Culberson County, Texas. The proposed Horseshoe Springs switch is located southwest of the intersection of FM 652 and FM 2185 in Culberson County, while the proposed Owl Hills substation is located west of US 285 near the Culberson County/Reeves County line, Oncor added.
The project includes building the Horseshoe switch station and half of the Owl Hills substation. Oncor also said that the other half of the Owl Hills substation is in conjunction with the proposed Owl Hills-Tunstill 138-kV Line (Docket No. 48582).
The length of the line ranges between about 18.3 miles to 31.5 miles, depending on which route is selected by the commission.
Oncor also said the Horseshoe Springs-Owl Hills line and associated station work was reviewed 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 and board.
Oncor 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, the new line in Culberson County is being proposed to connect Oncor’s Horseshoe Springs switch station to the company’s Owl Hills substation. Oncor added that the new line, in conjunction with the proposed Owl Hills-Tunstill line, would create a new 138-kV transmission circuit between the Horseshoe Springs switch station and the Riverton switch station.
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. The Horseshoe Springs switch station is the future site for a dynamic reactive device (DRD) and 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. One future 345-kV injection at Riverton is the subject of ongoing commission Docket No. 48095, regarding the Odessa EHV-Riverton and Moss-Riverton 345-kV lines, Oncor added. Creating a new electrical connection between those two points would result in a 138-kV system that would become more networked and allow bi-directional flow in the area, ultimately allowing the voltage support from the DRD and the 345-kV injection to address the reliability concerns during outage conditions, Oncor said.
The company 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.
The project area is situated in a relatively remote portion of Culberson County, Oncor added, noting that no incorporated cities, unincorporated towns, or communities are located within the project area. Nearly the entirety of the study area consists of rural, undeveloped land used primarily for livestock grazing or oil and gas production. Oncor also said that residential and commercial development is scarce.
Noting that it retained Halff Associates, Inc., to prepare the environmental assessment and routing study for the project, Oncor said that it selected Route 508 as the route that best addresses certain requirements.
As noted in the filing, of the 34 filed routes, Route 508 is about 11.6 miles longer than the shortest alternative route (Route 1) and estimated to cost about $11.7m more than the least expensive alternative route (Route 1). That additional cost can be justified by looking at the future expenditure that would be needed to build a 138-kV line from the proposed transmission line project to the Alligator Draw substation and the Chimney Well POD.
The company said, for instance, that:
- Route 508 is about 29.9 miles long, which is about 1.6 miles shorter than the longest alternative route included in the application; Route 1 is the shortest at about 18.3 miles long
- Route 508 is estimated to cost about $34m
- There are no habitable structures within the proposed right of way (ROW) of Route 508
- There are no habitable structures within 300 feet of the centerline of Route 508
- Route 508 parallels existing compatible corridors, including existing transmission lines, for about 23% of its length
- Route 508 crosses no recorded cultural resource sites
Among other things, the company said in its application that no parks or recreational areas owned by a government body or an organized group, club or church were identified within the study area or located within 1,000 feet of any of the proposed route centerlines of the proposed project.
According to the estimated schedule, engineering and design is to begin in November and be completed in April 2019; ROW and land acquisition is to begin in January 2019 and be completed in June 2019; material and equipment procurement is to begin in February 2019 and be completed in June 2019; and construction of the facilities is to begin in April 2019 and be completed in September 2019, which is also when the facilities would be energized.