A proposed $72 million, 40-mile-long transmission line between Piedmont and Luther advanced another step last week with the signing of an Interconnection Agreement by the involved parties.
The deal for the 345-kilovolt Mathewson-Redbud transmission line, expected to be finished by 2027-2028, was agreed to by Transource Oklahoma and AEP Oklahoma Transmission Co., with the Southwest Power Pool as signatory. Transource Oklahoma is a partnership between American Electric Power and Evergy.
The line is being built reportedly to “enhance grid reliability and reduce costs.” The developers claim it will provide $16.8 million in initial congestion savings. Supported by the SPP, it is designed to increase power reliability in the central part of the state and reportedly will lead to estimated savings of $138 million to $225 million over four decades.
A recent announcement from the SPP said the Interconnection Agreement was signed Dec. 19, 2025.
The SPP stated, “The filing was publicly noticed. No protests or adverse comments were filed. Pursuant to Rule 214 of the Commission’s regulations ... notices of intervention, timely-filed motions to intervene, and any unopposed motions to intervene out-oftime filed before the issuance date of this order are granted.”
It also represented final agency action.
The SPP selected Transource to construct the Oklahoma Transmission Project in May of last year.