Xcel Energy’s (NYSE:XEL) Southwestern Public Service (SPS) recently filed an application with the Public Utility Commission of Texas to amend a certificate of convenience and necessity in order to build and operate a 115-kV primarily single-circuit electric transmission line between the existing Bailey County substation, the New Amherst substation, and the existing Lamb County substation.
The company also seeks approval to concurrently connect to and convert one existing distribution substation to 115-kV service and connect two distribution substations at 115-kV service.
The Southwest Power Pool (SPP) issued a notification to construct (NTC) for the proposed project as needed for reliability to address: the overload issues of the Lamb County substation 115/69-kV transformer, which could occur during an outage of the parallel 115/69-kV transformer; and the low voltage at the East Muleshoe substation 115-kV bus for the outage of the East Muleshoe-Plant X 115-kV line, SPS said.
The proposed project would result in the removal of electrical load from the currently overburdened 69-kV system by transferring load to the 115-kV system; thus, the proposed project would result in an increase in load capacity and significantly better electrical reliability for customers in this service territory, according to SPS.
To accomplish the movement of load to the 115-kV system, the proposed project would involve the construction of the new 115-kV transmission line with two separate portions that would both interconnect with the New Amherst substation, SPS said.
The first portion of the proposed project (also referred to as “Bailey to New Amherst") would originate at the existing Bailey County substation, located about 1.1 miles southwest of Muleshoe, Texas, on TX Highway 214, about one mile southwest of the intersection of US Highway 84 and US Highway 70, SPS said.
The first portion would terminate at the New Amherst substation to be built about 1.3 miles southwest of Amherst, Texas, at the intersection of County Road 242 and FM 37. SPS also said that the existing 115-kV ring bus at the Bailey County substation would be upgraded to a breaker and a half scheme and a new terminal would be added to accommodate the new transmission line.
The Bailey to New Amherst portion involves the existing distribution Bailey County Pump substation, and the new distribution Hornet substation, SPS said, adding that the existing distribution Bailey County Pump substation – located at the intersection of US 84 and County Road 243 – would be converted from 69-kV to 115-kV service.
The existing distribution 69-kV Sudan Rural substation – presently located at the southwest corner of the intersection of US 84 and Barron Street in Sudan, Texas – would be replaced by the new distribution Hornet substation, to be built for 115-kV service and located on US 84 about 0.87 miles southeast of Sudan, Texas, SPS said.
Depending on the selected alternative route, the construction of a radial tap may be required from the new line to one or both of those substations, SPS said, adding that the New Amherst substation (transmission and distribution) would be built in a 115-kV ring bus scheme; and replace the existing distribution 69-kV Amherst substation presently located at the northeast corner of the intersection of Washington Avenue and Tenth Street in Amherst, Texas.
The second portion of the proposed project (also referred to as "New Amherst to Lamb") would originate at the New Amherst substation, and terminate at the existing Lamb County substation, located about 2.6 miles south of Littlefield, Texas, on US 385, at County Road 324, SPS said.
An expansion and reconfiguration of the Lamb County substation to a 115-kV breaker and a half scheme would be required to accommodate the new transmission line. The company added that to accommodate that expansion, one existing 230-kV circuit and two existing 115-kV circuits would need to be rerouted and re-terminated into that new bus design. The New Amherst to Lamb portion involves the existing distribution New Amherst substation, and the Lamb substation.
SPS added that the distribution substation conversions would render about 28.2 miles of the existing 69-kV Bailey County Substation to Lamb County Substation transmission line (Y80) idle, which would be retired and removed as part of the proposed project. Additionally, the approximately 8.4-mile remaining segment of Y80 would be rerouted and re-terminated at the New Amherst substation to maintain the existing 69-kV transmission service currently provided to Lamb County Electric Cooperative for its Beck, Amherst and Sandhill substations, SPS said.
Noting that the proposed 115-kV single circuit transmission line would be built utilizing primarily single-pole steel structures, SPS said that in alternative segments where the proposed circuit would coincide with the alignment that is currently occupied by an existing circuit on double-circuit wood H-frame structures, new double-circuit wood H-frame structures would be used to accommodate both the proposed and existing circuits.
The proposed line would be built entirely on new right of way (ROW), with a proposed easement width of 70 feet. SPS also said that the ROW for the total project would be 42 miles to 57 miles long, depending on the alternative routes selected. The Bailey County substation to New Amherst substation portion of the project would have about 31 miles to 40 miles of ROW, while the New Amherst substation to Lamb County substation portion would have about 11 miles to 17 miles of ROW.
SPS added that the area where the transmission line would be located is largely agrarian with irrigated and non-irrigated crops, dairies, and associated feedlots. Active water wells that supply the city of Lubbock are scattered across the undeveloped "Muleshoe Sandhills" in Bailey County, SPS said, adding that natural features include playa lakes, sandhills, and undisturbed areas with varying degrees of wildlife habitat value. The substations are located within more densely populated areas along Highway 84, which are paralleled by active railroad tracks, SPS said. Existing electric transmission lines run throughout the area where the transmission line would be located, the company said.
SPS noted that TRC Environmental Corporation, which prepared an environmental assessment (EA) for the proposed project, determined that Alternative Routes BN1 between the Bailey County substation and the New Amherst substation and NL1 between the New Amherst substation and the Lamb County substation best meet the commission’s routing criteria related to land use, aesthetics, ecology, and cultural resources, as well as other requirements.
According to the Bailey-New Amherst-Lamb 115-kV Transmission Line Project webpage, the project’s estimated cost is $50m, and proposed in-service date is March 15, 2022.