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Tri-State Proposes Transmission System Additions and Upgrades in Eastern Colorado

March 15, 2022
Coupled with other minor upgrades and a previously approved third transmission line project, these lines will enable the Tri-State system to accommodate more than 700 MW of potential new generating capacity.

Wholesale power supply cooperative Tri-State Generation and Transmission Association announced last month that it has filed with the Colorado Public Utilities Commission (CPUC) for approval of two new transmission lines in eastern Colorado.

Coupled with other minor upgrades and a previously approved third transmission line project, these lines will enable the Tri-State system to accommodate more than 700 megawatts of potential new generating capacity, improve reliability and close transmission system gaps in southeastern Colorado.

In filing for “certificates of public convenience and necessity” (CPCNs) with the CPUC for its eastern Colorado transmission upgrades, Tri-State noted that it is taking an incremental and pragmatic approach to additional transmission needs on its system. The capital investment in the four major segments to be constructed is estimated to be $185.6 million.

“By strategically and cost effectively interconnecting three new transmission lines into our existing network and improving an existing transmission line, we will ensure power reliability, eliminate bottlenecks in our system, and support significant clean energy additions as part of our transformative Responsible Energy Plan,” said Duane Highley, CEO for Tri-State. “Our electric resource plan before the CPUC identifies the need for an additional 2,000 megawatts of renewable resources across our interconnected system, and these transmission upgrades will help us achieve our aggressive greenhouse gas emission reductions goals.”

With the participation of more than 60 stakeholders representing 24 entities, Tri-State led a Task Force at the Colorado Coordinated Planning Group to evaluate alternatives to meet its transmission needs in eastern Colorado. Stakeholders proposed and Tri-State studied 15 alternatives through seven meetings between April and September of 2021. Of the alternatives studied, the proposed projects stood out as the best option that could meet Tri-State's needs, while at the same time being the lowest cost. 

In its filing, Tri-State requests CPUC approval for two projects. The first is a new, 30-mile, 230-kilovolt transmission line from its Boone Substation near Boone, Colo., to a new Huckleberry switching station south of Pueblo, Colo. The second is a new, 80-mile, 230-kilovolt transmission line between its Big Sandy Substation near Limon, Colo., and a new Badger Creek switching station south of Fort Morgan, Colo.

Tri-State also is constructing the previously approved, 230-kilovolt transmission line between its Burlington, Colo., and Lamar, Colo., substations, and will modify certain structures on its existing Big Sandy-Burlington 230-kilovolt transmission line, which does not require a CPCN. The enclosed map shows the approximate locations of the proposed new transmission lines and substations.

The filing for a CPCN with regulators requires Tri-State to demonstrate that the public interest supports the need for the projects. Details on specific routes for the projects are not required at this time and will be developed through the local government permitting processes. Tri-State will begin the siting process upon CPUC approval of the transmission line and substation proposals.

Project specifically supports unique needs of Tri-State's members

While Tri-State supports all statewide transmission infrastructure development in the state, it notes that its project is separate from Colorado’s Power Pathway (CPP), a $1.7 billion proposal by Xcel Energy to deliver generation to the Front Range of Colorado.

Tri-State's studies confirm that the CPP project and Tri-State's proposed transmission system improvements will not interfere with each other, and together will help achieve Colorado’s renewable energy and greenhouse gas emission reduction goals.

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