Oklahoma regulators are being asked to grant approval for construction of a major electric transmission project that would cross the Oklahoma Panhandle and connect the eastern and western U.S. power grids.
Three Corners Connector seeks Oklahoma approval
Three Corners Connector LLC has filed an application with the Oklahoma Corporation Commission seeking authority to construct a portion of a 300-mile, $2 billion high-voltage transmission line known as the Three Corners Connector. The project would involve construction of an up to 525-kilovolt high-voltage direct current (HVDC) transmission line with endpoints near Guymon, Oklahoma, and Pueblo, Colorado.
According to the filing, the line would transport electricity from all generation sources and allow bidirectional power flows to respond to shifting demand between regions.
Project developer and ownership structure
Three Corners Connector LLC is a subsidiary of Grid United LLC, a Texas-based transmission development company. Grid United is wholly owned by Centaurus Capital LP, the Houston-based family office of John and Laura Arnold.
Grid United is led by CEO Michael Skelly and CTO Kris Zadlo, both of whom have decades of experience developing and integrating large-scale transmission projects across global power grids.
Cost breakdown and potential rate impacts
The total estimated cost of the full Three Corners Connector project is $2.133 billion. The Oklahoma portion alone is estimated at $862.3 million, according to the filing.
That Oklahoma cost includes:
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$183.6 million for HVDC and AC transmission lines
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$566 million for the converter station
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$24.5 million for network upgrades
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$52.5 million for the point of interconnection
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$11.4 million for post–notice-to-proceed land costs
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$24.3 million for development costs
How much of those costs could ultimately be borne by Oklahoma ratepayers has not yet been determined and will be addressed in a future Corporation Commission docket.
Route through the Oklahoma Panhandle
Plans call for construction of 66.24 miles of HVDC transmission line and 9.04 miles of alternating current transmission line across Cimarron and Texas counties in the Oklahoma Panhandle.
The HVDC segment enters Cimarron County from Baca County, Colorado, approximately six miles west of Texas County. From there, the line:
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Crosses U.S. Highway 56
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Proceeds southeast to State Highway 95
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Continues eastward north of Goff Creek for roughly 24 miles
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Crosses State Highway 136, about eight miles north of Guymon
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Advances southeast to U.S. Highway 54, southwest of Optima
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Turns south to cross Highway 412 and enter the converter station site
At the converter station, electricity would be converted from direct current to alternating current.
Three Corners Connector said it has already secured voluntary land option agreements for 100% of the proposed route in Texas and Cimarron counties.
Converter station and grid interconnection
The project includes one converter station in Texas County, one converter station in Pueblo, Colorado, and a fiber repeater station. The line is designed to bridge the Western Interconnection and the Southwest Power Pool (SPP) in the Eastern Interconnection.
According to the company, the connector would link SPP with Public Service Company of Colorado (PSCo), allowing firm transfers of electricity between two regions with non-coincident peak demand.
Grid reliability and Winter Storm Uri example
In its filing, Three Corners Connector cited Winter Storm Uri in 2021 as an example of why interregional transmission is needed. The company said the storm caused severe price spikes across Oklahoma.
Average locational marginal prices in the OG&E load zone reached $1,490 per megawatt-hour, compared with $242 per megawatt-hour in the PSCo load zone.
“Had it been operational during this period, the Project would have provided access to lower-cost energy from PSCo, reducing both the severity and duration of Oklahoma’s price spikes,” the filing stated.
The company estimated that with 1,800 megawatts of transfer capability, the line could have enabled approximately $162 million in customer savings over a three-day period.
Economic and operational benefits cited
Three Corners Connector contends the project would enhance grid resiliency, support economic development, and generate benefits through tax revenues, landowner payments, and job creation. The line would not be tied to any specific generation resource and would remain open to all electricity sources.