South Texas Electric Cooperative seeks approval of 138-kV line in Texas to connect wind project

South Texas Electric Cooperative, Inc., (STEC) on July 25 filed with the Public Utility Commission of Texas an application to amend its certificate of convenience and necessity for the proposed Palmas to East Rio Hondo 138-kV Transmission Line in Cameron County, Texas.

STEC said that it is seeking approval to build the double-circuit, overhead line to connect the Palmas Wind Energy Project to the ERCOT grid. Palmas Wind, LLC requested that STEC interconnect its Palmas Wind Energy Project generating facilities at the Palmas station, which would be owned by STEC. The wind generation facility will be comprised of 46 wind turbine generators rated 3.15 MW each with a total nominal capacity of about 145 MW, STEC added.

STEC said that its 138-kV East Rio Hondo substation, which is generally south of the Palmas wind farm collection facility, is the closest transmission substation

The entire route is in Cameron County, Texas, with the south end connecting to STEC’s East Rio Hondo substation, located about three miles east of Rio Hondo, Texas, at the northwest quadrant of the FM 106 and FM 2925 intersection. The north end of the line would connect to the Palmas station, located along the east side of Olmito Rd., about six miles northeast of the East Rio Hondo substation where the wind generation gathering facility is located, STEC added.

The proposed line would be designed double-circuit-capable but would initially be built with only one circuit installed, STEC said, adding that commission approval of both circuits of the proposed line is requested. The investment in davit arms, insulators, conductor, and second poles at angle structures would be deferred until additional transfer capacity is needed and the second circuit is added, STEC said.

The length of the line ranges between 6.2 miles and 6.6 miles in length, depending on which route is selected by the commission.

The study area is located in the Gulf Coastal Prairies region and is characterized by nearly flat grasslands composed of young deltaic sands, silt, and clay, STEC added. The study area is primarily rural with scattered residential development. STEC also said that the predominant land use within the study area is cropland and rangeland/pastureland. The majority of the study area has been impacted by land improvements associated with agriculture, residential structures, roadways, and various utility corridors, STEC noted.

POWER Engineers prepared an environmental assessment (EA) and routing study for the project. STEC added that the consensus opinion of POWER evaluators was to recommend “Route B” as the route that best addresses certain requirements from an environmental and land use perspective. POWER’s evaluation indicates how closely the top two ranked alternative routes, Route B and “Route H” are compared from an environmental and land use perspective. STEC also said that the estimated cost of Route B is about 5% lower than that of Route H, which crosses three fewer landowner properties than any other route.

STEC said that it considers each of the eight alternative routes provided by POWER viable for the proposed project. STEC said that based on the minimal differences between routes B and H identified by POWER and weighted with certain factors, it is STEC’s opinion that alternative Route H provides the best balance of routing characteristics and best addresses certain requirements.

To install the initial 138-kV circuit along Route H, it would cost about $6.5m for the transmission facilities portion of the project; about $2.7m for the East Rio Hondo facilities; and about $1.9m for the Palmas facilities, STEC said.

None of the eight alternative routes cross any parks or recreational areas or are located within 1,000 feet of any park or recreational area, STEC said. Also, none of those routes cross or are located within 1,000 feet of any recorded archaeological sites, STEC said.

Among other things, STEC said that according to the project’s estimated schedule, right of way and land acquisition would begin in November and be completed in February 2019; engineering and design would begin in January 2019 and be completed in February 2019; material and equipment procurement would begin in January 2019 and be completed in March 2019; construction of the facilities would begin in March 2019 and be completed in June 2019; and the facilities would be energized from June 2019 to September 2019.

Article amended at 1:12 p.m., EST, on Monday, July 30, 2018, to note that the name of the entity filing the application is South Texas Electric Cooperative, Inc.

About Corina Rivera-Linares 3065 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.