Just the Facts

The San Luis Valley-Calumet-Comanche Transmission Project is a single, joint project proposed by two electric utilities - Tri-State Generation and Transmission Association, Inc. (Tri-State) and Public Service of Colorado (PSCo), an Xcel Energy company.

The Current Situation

  • There is plausible concern in south-central Colorado regarding the reliability of existing electricity service if additional transmission lines are not constructed to relieve congestion, increase capacity of the current power delivery system and provide needed infrastructure for investment in renewable resources.
  • Growth in residential and agricultural areas throughout the region has caused the existing transmission infrastructure to reach its limit, requiring investments to increase capacity into and out of this part of Colorado.

  • New state mandates have directed utilities to expand Colorado's electric transmission system and promote the use of renewable resources.

Purpose and Need

  • The project is intended to address reliability concerns and facilitate the development of renewable energy in south-central Colorado by using one common set of transmission facilities, which lessens environmental and land use impacts that would result from two separate projects and saves consumers money.
  • The joint project provides:
    • long-term solutions to improve the electric service and increase reliability for Tri-State and Xcel Energy customers in south central Colorado and northern New Mexico;
    • a transmission outlet for beneficial energy resources, including renewable energy generation in south-central Colorado;
    • a common long-term solution to reliability and renewable generation needs, rather than short-term fixes or duplicative facilities.


  • Currently, both the San Luis Valley and Walsenburg areas are served by an aging, radial transmission infrastructure. A radial infrastructure consists of lines that run in one direction or from one source and ultimately dead-end, causing reliability concerns.
  • The proposed project will enhance Tri-State's ability to provide reliable service to its members in southern Colorado and northeastern New Mexico. The project will eliminate the existing radial infrastructure and create a looped transmission system between the San Luis Valley and the Pueblo and Walsenburg areas. This, in turn, will create a reliable, secondary path for electricity between both areas.

Renewable Energy

  • The proposed project would help facilitate interconnection of new solar generation sources to Colorado's power delivery infrastructure and provide the needed capacity to support the development of renewable resources and support state renewable energy standards.
  • The proposed project would help meet the goals of Colorado Senate Bill 07-100, which requires rate regulated utilities, such as Xcel Energy, to plan transmission projects in areas shown to be constrained that accommodate the development of beneficial resources, including renewable generation.

Transmission Alternatives

  • Since 1997, Tri-State, either on its own or with the participation of others, has evaluated a number of electric system alternatives in various transmission planning studies to determine the best and most cost-effective solution to the purpose and need.
  • The project that resulted from the earlier studies was the San Luis Valley Electric System Improvement Project (the "SLVESIP") (see the 2008 Alternatives Evaluation/Macro Corridor Study). This project consisted of a transmission line that would connect the San Luis Valley Substation with the Walsenburg Substation.

Since that time and through further studies, this current joint project with Xcel Energy has been shown to be the best solution for addressing both Tri-State's and Xcel Energy's reliability concerns and for facilitating the interconnection and export of renewable resources out of the San Luis Valley and Walsenburg areas.

  • As a result of this extensive analysis, the proposed project was identified as the system alternative that:
    • best meets the joint needs of both utilities;
    • ensures a robust and reliable system to serve the utilities' consumers;
    • has the greatest export capacity;
    • possess the flexibility to expand;
    • demonstrates reasonable costs;
    • has lesser effects to communities, the environment and property owners.
  • Tri-State and Xcel Energy are currently conducting a routing process to identify a preferred route and feasible alternative routes that will be evaluated in the federal environmental review process and presented to local county jurisdictions for necessary land use permits.


This transmission project is a cost-effective project needed to meet the challenges identified by the Colorado General Assembly, the Governor's Energy Office, the Colorado Public Utilities Commission, and numerous stakeholders.

The project is essential to meeting Colorado's goals of clean, reliable, affordable, and secure electrical power now and in the future.


In the News

Power line generates public comments
Valley Courier
April 27, 2012


SLV power line headed back to drawing board
Pueblo Chieftain
April 27, 2012


Support for San Luis Valley line isn't powering down
Denver Post
November 2, 2011


Xcel is out, but transmission line is not
Valley Courier
November 2, 2011


Xcel likely to drop SLV solar, transmission line proposal
Pueblo Chieftain
November 1, 2011


San Luis Valley Power
Pueblo Chieftain
September 14, 2011


Colorado PUC reaffirms approval of San Luis Valley power line sought by Xcel, Tri-State
Denver Business Journal
September 2, 2011




This Web site is hosted and maintained by Tri-State and Xcel Energy. The goal is to provide Colorado residents with facts and details of transmission development as we work to provide safe, reliable electricity. We encourage and appreciate public input to the process.

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