The Public Utility Commission of Texas amends South Texas Electric Cooperative’s (STEC) certificate of convenience and necessity (CCN) to include the construction and operation of the Palmas-to-East Rio Hondo 138-kV transmission line using modified route H, according to a Feb. 5 notice of approval signed by commission counsel.
As noted in the filing, STEC in July 2018 filed an application with the commission to amend its CCN for authority to build, own, and operate the double-circuit-capable line in Cameron County.
The proposed line is needed to connect wind generation facilities to the ERCOT grid, the filing said, noting that Palmas Wind, LLC requested that STEC interconnect the Palmas Wind Energy project generation facilities, which will have an output capacity of 145 MW net at the point of interconnection, to the proposed Palmas switching station, which would then connect to STEC’s existing East Rio Hondo substation through the proposed line.
Palmas Wind executed ERCOT’s standard generation interconnection agreement with STEC for the interconnection of the wind farm generation facility, the filing said.
Parties to the proceeding in October 2018 filed a unanimous settlement agreement, under which the proposed line would be built on modified route H. That route follows the original route H except that, on the south end of the proposed route, segment 30 is replaced by segments 27 and 29, the filing added. Modified route H, which has about 6.2 miles of right of way (ROW), comprises segments 1, 6, 13, 20, 25, 28, 27, 29, and 31. STEC agreed to build the line as a single-circuit, 138-kV line on double-circuit-capable monopole structures following modified route H. The filing also noted that the typical structure for the line would be about 85 to 120 feet in height, and would require a 100-foot-wide ROW.
The estimated costs are about $6.1m for the proposed line along modified route H, as well as about $4.6m for the East Rio Hondo substation facilities and the Palmas switching station facilities.
STEC’s existing East Rio Hondo substation would have additional facilities built to connect to the new line, the filing noted, adding that the new Palmas switching station would be built on STEC property adjacent to the Palmas Wind Energy Project collection facility.
Modified route H is the shortest of all of the proposed routes, crosses the least amount of cropland, and parallels existing property lines, as well as existing transmission lines, to a large extent. The filing added that all directly affected landowners who intervened in the proceeding agreed to modified route H, which “will have minimal impacts on community values.”
The proposed line would not adversely impact parks and recreational areas, and it is not expected to have an adverse impact on historical or archaeological areas, the filing said.
Among other things, the filing said that STEC must conduct surveys, if not already completed, to identify metallic pipelines that could be affected by the line and coordinate with pipeline owners in modeling and analyzing potential hazards because of alternating current interference affecting pipelines being paralleled.
Also, the filing noted that before beginning construction, STEC must undertake appropriate measures to identify whether a potential habitat for endangered or threatened species exists and must respond as required.