Tex-La Electric Cooperative of Texas, Inc., (TEXLA) on Jan. 31 filed with the Public Utility Commission (PUC) of Texas an application to amend its certificate of convenience and necessity (CCN) for the proposed Martinsville to Chireno 138-kV Transmission Line project in Nacogdoches County, Texas.
TEXLA’s Tenaha switching station, Deep East Texas Electric Cooperative, Inc.’s (DETEC) and TEXLA’s Timpson and Fitze substations, as well as DETEC’s Martinsville substation would be included in the project, the filing noted. They will require upgrades to allow for sectionalizing of the facilities between the Tenaha switching station and the proposed Chireno switching station; TEXLA would build the new Chireno switching station as part of the proposed transmission line, according to the filing.
Discussing the need for the proposed project, the filing noted that TEXLA and DETEC are proposing construction of certain transmission facilities to provide looped 138-kV transmission service to members of the cooperative. Currently, DETEC, a member of TEXLA, serves its members through a radial 138-kV transmission line that begins at TEXLA’s Tenaha switching station and terminates at DETEC’s Martinsville substation.
There are six substations that are currently served via those radial transmission facilities from TEXLA’s Tenaha switching station, and those six substations provide a total of 48 MW to cooperative members during peak loading conditions.
The filing added that TEXLA and DETEC have been planning closed loop facilities for the DETEC service area since about 2007 in order to improve reliability to members in the DETEC service area. The construction of projects to increase reliability on the transmission network started with DETEC’s CCN amendment request with the PUC for the Chireno to Etoile project, the filing noted. The completion of this project allowed for contingency refeed of facilities in the instance of a major event and was not operated as closed loop at the time, the filing said.
The next step in the process required facilities from DETEC’s Timpson to DETEC’s Martinsville substations to be converted to 138-kV operation, the filing said, adding that this included conversion to 138-kV of these facilities: TEXLA’s Timpson switching station, TEXLA’s Fitze substation, and the transmission facilities between TEXLA’s Timpson and DETEC’s Central Heights substations.
The most recent project that has been completed as part of increasing the reliability to the area was the upgrade of facilities between TEXLA’s Center switching station, TEXLA’s Holly Auto Station, TEXLA’s Leach switching station, and TEXLA’s Mill Creek switching station to closed loop operation, according to the filing. That latest upgrade to the transmission network was completed in December 2015, and is operated closed loop as of that date, the filing said.
The last step in completing the transmission reliability projects in the DETEC service area is to build the proposed transmission project, the filing said, noting that the conversion to 138-kV – from 69-kV – of TEXLA’s Timpson switching station to DETEC’s Martinsville substation brought the entire TEXLA Tenaha switching station to DETEC Martinsville substation up to 138-kV for the entire length.
The proposed Martinsville to Chireno project would allow for closed loop operation to that section of transmission facilities that is currently served radially, the filing said, adding that the previously mentioned 48 MW of load would benefit from automatic sectionalizing of facilities in the event of an outage on a line section.
The plan for closed loop operation of the facilities would include breakers at DETEC’s Martinsville substation, TEXLA’s Central Heights substation, TEXLA’s Timpson switching station, and TEXLA’s Tenaha switching station.
The filing also noted that TEXLA retained POWER Engineers Inc., to prepare an environmental assessment and alternative route analysis for the proposed project. The study area for the project is oriented in a northwest to southeast direction that ranges from three miles to eight west to east and 4.5 miles to nine miles north to south, and encompasses about 62 square miles in Nacogdoches County. The study area is located within the Interior Coastal Plains sub-province of the Gulf Coastal Plains Physiographic Region of Texas and is characterized by pine and hardwood forest, as well as numerous permanent streams, the filing said.
The filing also noted that TEXLA concluded that “Route 7” is the route that best addresses certain requirements, based on such advantages as that Route 7:
- Has the second lowest estimated cost at about $11.7m
- Is tied with “Route 9” as the second shortest route at 11 miles
- Utilizes or parallels existing linear features – transmission lines, other existing compatible right of way (ROW), or apparent property lines or other natural or cultural features – for 91% of its length
- Has the shortest length of ROW across bottomland and riparian woodlands – 0.5 mile
- Has the least number of stream or river crossings – 14 total
- Does not parallel – within 100 feet – any streams or rivers
- Has the shortest length of ROW across areas of high archaeological potential – 4.4 miles
According to the filing, there are 29 habitable structures within 300 feet of the ROW centerline.
Among other things, the filing noted that if the project is approved, ROW acquisition would begin in January 2018 and be completed in June 2018; engineering and design would begin in June 2018 and be completed in August 2018; material and equipment procurement would begin in August 2018 and be completed in December 2018; construction of the facilities would begin in January 2019 and be completed in April 2019; and the facilities would be energized in May 2019.
As noted in a Jan. 31 document addressed to a landowner, included in the filing, the total estimated cost of the transmission project is between about $11.3m and about $14.2m, dependent upon which route the PUC selects. Additional costs associated with the proposed project include upgrading four existing substations for a total cost of about $3.4m, plus the new Chireno switching station with a total cost of about $2.6m. Accordingly, the document added, the total estimated cost of the proposed project is between about $17.3m and about $20.2m.