Oncor proposes 138-kV transmission line in Texas

Oncor Electric Delivery Company on April 10 filed with the Public Utility Commission (PUC) of Texas an application for a certificate of convenience and necessity (CCN) regarding its proposed Littman-Phillips Andrews Tap 138-kV Transmission Line Project.

The company said that the approximately 11.1-mile, double-circuit capable line, with one circuit in place initially, would connect the existing Oncor Littman substation, located in northwest Andrews County near the southwest intersection of State Highway (SH) 176 and the Texas-New Mexico state line, to the proposed Phillips Andrews Tap, to be located about 2.75 miles northeast from the intersection of Nelson Road and SH 176 in Andrews County.

The estimated total cost of the transmission facilities is about $9.7m, while the estimated total cost of the substation facilities is $452,000, Oncor said, noting that the station facility costs account for the necessary equipment to modify the existing substation to accommodate the proposed line.

Discussing the need for the proposed project, Oncor said that ERCOT stakeholders reviewed the proposed line and associated station work through the ERCOT Regional Planning Group Project Review Process as part of Oncor’s proposed Littman-Fullerton 138-kV Line project, of which the proposed project is a sub-section.

Oncor also said that the proposed project supports continued load growth on the existing 138-kV substations in Andrews County, provides transmission facilities in an area without transmission facilities to serve new substations, and improves reliability by providing an alternative transmission feed to radially fed substations.

The proposed project also provides operational flexibility in response to transmission line outages, obtaining clearances for maintenance of equipment or upgrading of facilities, and connecting new load to the system.

Oncor added that it continues to experience load growth in West Texas due to oil and natural gas production, mid-stream processing, and associated economic expansion in the area referred to as the Permian Basin.

The company further noted that the proposed project would establish high-voltage transmission service closer to customers in an area of Andrews County where additional substation capacity will likely be installed to meet future load growth. Additionally, the proposed project would create a second pathway for electricity to flow into The Andrews Loop from the main source, the Andrews County South 345/138-kV autotransformer, Oncor said, noting that that second 138-kV pathway would supplement the Andrews North switching station, which is the central hub for the 138-kV and 69-kV transmission lines in the area, and is currently the only 138-kV source for The Andrews Loop.

In addition, the proposed project is needed to improve reliability on the Andrews County South-Littman 138-kV Line, which is a 25-mile radial line, and the Phillips Andrews Tap 69-kV Line, which is a 5.5-mile radial line that is connected to the 44-mile Andrews North-Andrews 69-kV Transmission Line, Oncor said.

The company noted that it selected the double-circuit 138-kV steel and concrete monopoles for numerous reasons, including costs, technical specifications, structure footprint, and right of way (ROW) requirements.

The landscape is mostly open shrub-land, consisting of desert-grass shrub vegetation and mixed prairie grasses, the company said. The proposed route would be built in Andrews County, and would not traverse any municipality, Oncor said.

The company said that it retained Halff Associates to prepare the environmental assessment for the proposed project.

No known habitable structures were identified within 300 feet of the proposed route, the company said.

Oncor also said that Texas Historic Commission records indicated no National Register of Historic Places, State Antiquities Landmarks, or cemeteries recorded within 1,000 feet of the proposed route centerline.

The environmental assessment noted, for instance, that many of the listed threatened or endangered species that may be found in the study area are migratory birds. Among other things, the environmental assessment said that bald eagle populations are being monitored, and that since the study area lacks large trees and a major water source, it is unlikely that the bald eagle would occur in the study area.

According to the estimated schedule included in the application, ROW and land acquisition would begin in November – contingent upon the CCN approval process at the PUC – and be completed in June 2018; engineering and design would also begin in November and be completed in June 2018; material and equipment procurement would begin in April 2018, and be completed in October 2018; and construction of facilities would begin in July 2018, and be completed in December 2018, which is when the facilities would be energized.

About Corina Rivera-Linares 3286 Articles
Corina Rivera-Linares was TransmissionHub’s chief editor until August 2021, as well as part of the team that established TransmissionHub in 2011. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial from 2005 to 2011. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines.