MISO has announced that Ameren Transmission Company of Illinois (ATXI) will lead development of the Denny – Zachary – Thomas Hill – Maywood 345 kV Competitive Transmission Project. ATXI’s proposal included a partnership with The Missouri Joint Municipal Electric Utility Commission d/b/a Missouri Electric Commission (MEC).
This project is the fifth competitively bid project from the Long Range Transmission Planning (LRTP) Tranche 1 portfolio approved by MISO’s board of directors in 2022 and the largest competitive project MISO has ever evaluated with an estimated implementation cost of $273 million (in nominal dollars) for the three transmission lines included in the scope of the project.
“The selected proposal had a substantially lower cost than that of the next closest developer,” said Jeremiah Doner, MISO’s director of cost allocation and competitive transmission. “ATXI’s proposal also features strong cost containment, sound design, and robust operations and maintenance plans.”
One new 345 kV line will connect the Denny substation to the Zachary substation and the second new 345 kV line will connect the Zachary substation to the Maywood substation, for approximately 162 line miles. The third 345 kV line is an approximately 42-mile, a conductor-only facility that will connect the Zachary substation to the Thomas Hill substation.
“ATXI will now move forward on executing the Selected Developer Agreement following a rigorous competitive selection process that included six proposals from four developers to construct, own, operate and maintain the project,” said Doner. “We look forward to working closely with the developer, regulators and other stakeholders to support a successful and on-time completion of the project.”
MISO evaluates proposals based on cost and design, project implementation, operations and maintenance, and transmission planning participation – all relevant factors in ensuring project success. MISO used the established criteria and competitive selection process as described in its Tariff to evaluate proposals, and ultimately to select the developer.
MISO issued a request for project proposals on June 2, 2023, and developers had until November 14, 2023, to complete submissions. This is the fifth of five competitive projects identified out of LRTP Tranche 1 to complete the competitive selection process. The project is expected to be in service by 2030. The complete selection report for the project is available on MISO’s Competitive Transmission webpage.
LRTP is a component of MISO’s Response to the Reliability Imperative – the shared responsibility of MISO and its stakeholders to address the urgent and complex challenges to the electric grid.
