Zorn–Marion 345-kV Transmission Line Project

LCRA TSC is building a new 345-kV transmission line to connect the existing Zorn and Marion substations in Guadalupe County. In September 2016, the Public Utility Commission of Texas approved the project and selected the route to build.


Bexar County and the Interstate 35 corridor between San Antonio and Austin have been growing at a steady pace for several years. Electric system planning assessments indicate existing transmission lines are not adequate to meet the growing demand for power. Additional 345-kV infrastructure is required to safely and reliably serve future demand for power in Bexar, Kendall, Comal and Guadalupe counties.

The new 345-kV transmission line and autotransformer additions at two existing substations are key elements of the required infrastructure.

LCRA TSC is building the 345-kV transmission line to connect its existing Zorn and Marion substations. Some portion of the line will use existing structures between the Zorn and Clear Springs substations. The remainder of the line will require new construction on new right of way.

Project Updates:

Aug. 24, 2018

Construction activities are underway for the transmission line and the expansion work at the Zorn and Marion substations. Transmission structure foundations are being drilled on the portion of the line from Marion to Clear Springs. Crews also are working on the existing structures from Clear Springs to Zorn in preparation for the additional circuit. The project remains on track for completion in June 2019.

Sept. 16, 2016:

The Public Utility Commission (PUC) of Texas approved the Zorn-Marion project and selected Route 10M, which consists of segments S2-I-M-T-V-Y-P1-T1-W1. Map of the PUC-approved route. PUC Final Order.

Zorn-Marion intervenor map as of June 14​, 2016.

On March 1, 2016, LCRA TSC filed an application with the Public Utility Commission of Texas (PUC) to amend its Certificate of Convenience and Necessity (CCN) to construct the proposed Zorn-Marion 345-kV Transmission Line Project in Guadalupe County. The PUC assigned Docket No. 45601 to this proceeding. Links to LCRA TSC's complete CCN application are available below and at the ​PUC Interchange (enter Docket No. 45601 into the Control Number field to find documents related to the project).

Also on March 1, LCRA TSC mailed notices to potentially affected landowners. Notices will be published in local newspapers on March 8.

LCRA TSC's CCN Application Files:

Attachments to the CCN Application

Interactive Mapping Tool: This tool allows you to zoom in and out using aerial imagery. It includes the primary alternate route segments and property line information obtained from the Guadalupe Appraisal District. This mapping tool has been updated to reflect the information included in LCRA TSC’s CCN application.

Early 2015:

  • The Electric Reliability Council of Texas (ERCOT) Regional Planning Group evaluated the need for the project, including various alternative solutions. 
  • After incorporating stakeholder input and completing its own assessment, ERCOT staff members presented their independent review findings to the ERCOT Technical Advisory Committee and subsequently to the ERCOT Board of Directors for endorsement consideration.
  • The ERCOT Board voted to endorse the project on April 14, 2015. ERCOT designated this project as critical for system reliability.
  • LCRA TSC's Board of Directors approved funding for the project in LCRA TSC's fiscal year 2016 capital plan on May 20, 2015.
  • LCRA TSC selected Power Engineers, an engineering and environmental consulting firm, to conduct the routing and environmental assessment phase of the project, which includes:
    • Delineation of the project study area.
    • Data collection.
    • Environmental and land use constraint mapping.
    • Identification of preliminary route segments.
  • Power Engineers delineated the project study area and began data collection and constraint mapping.
  • LCRA TSC sent letters to local, state and federal officials and agencies asking for information that could affect the transmission line route in the project area.


Fall 2015:

Open house: LCRA Transmission Services Corporation (TSC) hosted an open house on Sept. 17, 2015, at the Seguin Coliseum on the proposed Zorn-Marion 345-kV Transmission Line Project. Potentially affected landowners and elected officials attended to learn more about the project and provide input on the preliminary route segments. Potentially affected landowners are those listed on current county tax rolls as owners of land within 500 feet of the centerline of any proposed preliminary route segment. Open house notices also were published in area newspapers. The notice sent to landowners, associated documents, and links to the exhibits, maps and information LCRA TSC provided at the Sept. 17 open house include:

Open house exhibit boards: Includes informational boards displayed at the open house.

Land use constraint maps: U.S. Geological Survey topographic base maps depicting routing constraints and preliminary alternate route segments.
Map 1 – Western study area
Map 2 – Eastern study area

Aerial photos: Aerial imagery maps depicting routing constraints and preliminary alternate route segments.
Map 1 – Western study area
Map 2 – Eastern study area

Property ownership maps: Aerial imagery maps showing property lines based on Guadalupe County appraisal district data and preliminary alternate route segments.
Map 1 – Overall Property Ownership map
Map 2 –Property Ownership Insets map

Interactive Mapping Tool:
(High-speed Internet access recommended) This tool enables you to use aerial imagery to view alternate route segments and property line information.