Northern Missouri Grid Transformation Program

Ameren Transmission

Ameren Transmission Company of Illinois (ATXI), Missouri Joint Municipal Electric Utility Commission (MJMEUC) and Ameren Missouri are working together to build a more reliable and resilient energy grid for the future.  The Northern Missouri Grid Transformation Program is a portfolio of new energy projects that includes more than 255 miles of new 345 kilovolt (kV) transmission lines developed in two phases across northern Missouri.

About the Project

Phase 1 of the program includes the Fairport-Denny-Iowa/Missouri Border Project (FDIM) and the Maywood-Mississippi River Crossing (MMRX) Project. The first-phase projects are located in Worth, Gentry, DeKalb and Marion counties, with approximately 53 miles of new transmission line and a new substation.

The Northern Missouri Grid Transformation Program's Phase 2 includes the Denny-Zachary-Thomas Hill-Maywood (DZTM) Project, with more than 200 miles of new transmission lines across 10 counties in northern Missouri. The DZTM Project is in DeKalb, Daviess, Grundy, Sullivan, Adair, Knox, Lewis, Marion, Macon and Randolph counties. The Project also includes upgrades to existing Ameren substations.

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Community Benefits

Reliability

Improving energy reliability for the surrounding region and local communities

Growing Opportunities

Growing economic development opportunities

Energy Sources

Promoting access to diverse energy sources

Increased Capacity

Increasing transmission capacity to meet changing energy needs

Lower Costs

Supporting lower energy supply costs

All Routes Approved to Proceed

Our public process for the Northern Missouri Grid Transformation Program allowed careful consideration of feedback from landowners, community members, interested agencies and local officials throughout the routing process.

On Dec. 11, 2024, ATXI submitted an application to the Missouri Public Service Commission (PSC) for a Certificate of Convenience and Necessity (CCN) for the DZTM Project. On July 16, 2025, the Mo PSC approved a final route and issued a CCN for the DZTM Project. As part of the CCN, the PSC approved the Double Circuit Design for the Denny-Zachary line segment.

On July 16, 2024, ATXI submitted an application to the PSC for a CCN for the FDIM Project and MMRX Project. On Dec. 11, 2025, the PSC approval a final route and issued a CCN for the FDIM Project and MMRX Project. As a result, all phases of the Northern Missouri Grid Transformation Program have been approved to proceed.

For information on the Northern Missouri Grid Transformation Phase 1 (FDIM and MMRX) filing, visit the PSC docket website at Docket Sheet - EA-2024-0302. For information on the Phase 2 (DZTM) filing, visit Docket Sheet - EA-2025-0087. If you have questions or concerns about your property as it relates to the Program or would like more information on our Program, please contact us directly via our hotline at 1.833.799.1633 or email us connect@AmerenGridMO.com.

Phase 1: FDIM and MMRX

Fairport-Denny-Iowa/Missouri Border Project (FDIM)

The Fairport-Denny-Iowa/Missouri border (FDIM) Project includes the construction of approximately 44 miles of 345 kV transmission lines and a new 345 kV substation. The FDIM project will route through DeKalb, Gentry and Worth counties and will include two transmission line segments. The first new 345 kV transmission line segment will connect Associated Electric Cooperative Incorporated's (AECI) existing Fairport substation in DeKalb County to ATXI's new Denny substation approximately one mile away, also in DeKalb County. The second new 345 kV transmission line segment will run from the new Denny substation approximately 43 miles north to the Iowa/Missouri border.

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Maywood-Mississippi River Crossing Project (MMRX)

The Maywood-Mississippi River Crossing (MMRX) Project includes the construction of approximately 9 miles of 345 kV transmission line from ATXI's existing Maywood substation near Palmyra, Missouri across the Mississippi River to Illinois. The project includes upgrades to the Maywood substation.

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Winter 2024 through Summer 2024

Summer 2024

2025

2027

2029

2030

Project Planning, routing, and stakeholder/public engagement

Finalize route and file application with Missouri Public Service Commission (MoPSC)

Receive a Certificate of Convenience and Necessity decision from the MoPSC; real estate begins; permitting and agency coordination; environmental studies/surveys

Construction begins

Projects in service

Restoration complete

Phase 2: DZTM 

Denny-Zachary-Thomas Hill-Maywood Project (DZTM)

The Denny-Zachary-Thomas Hill-Maywood (DZTM) Project includes the construction of over 200 miles of new 345 kV transmission lines with three transmission line segments. The first new line segment of the project will run approximately 100 miles from ATXI's new Denny substation in DeKalb County to ATXI's existing Zachary substation near Kirksville, Missouri. A second new line segment, approximately 60 miles, will connect the existing Zachary substation to ATXI's existing Maywood substation near Palmyra, Missouri. A vast majority of the Zachary-Maywood line segment will be built along an existing corridor. The Project's third line segment consists of 44 miles rebuilt on Ameren's existing transmission corridor from the Zachary substation to AECI's existing Thomas Hill substation in Randolph County. The Project includes upgrades to existing Ameren substations.

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Summer 2024

Fall 2024

Mid 2025 - 2026

Spring 2027

Late Fall 2029

Spring 2030

Project Planning, routing, and stakeholder/public engagement

Finalize route and file application with Missouri Public Service Commission (MoPSC)

Receive a Certificate of Convenience and Necessity decision from the MoPSC; real estate begins; permitting and agency coordination; environmental studies/surveys

Construction begins

Projects in service

Restoration complete

We have a designated project hotline and email address that the public can use to contact members of our project team. Have a question? Please contact us using one of the methods below.

Phone: 1.833.799.1633

Email: connect@AmerenGridMO.com

General Information

What is the Northern Missouri Grid Transformation Program?

Ameren Transmission Company of Illinois (ATXI), Missouri Joint Municipal Electric Utility Commission (MJMEUC) and Ameren Missouri are working together to build a more reliable and resilient energy grid for the future. The Northern Missouri Grid Transformation Program is a portfolio of new energy projects that includes more than 255 miles of new 345 kV transmission lines developed in two phases across northern Missouri.

Why is the Program needed?

Just as additional roads need to be built or expanded over time, the program will prepare the grid for the future by adding transmission capacity. The program will also ensure energy reliability and resiliency while promoting greater access to energy sources for Northern Missouri communities and the region.

When will construction be complete?

We anticipate construction of the transmission line to begin in 2027, with varying start dates for each line segment. Construction at new or existing substations may begin earlier. All projects within the Northern Missouri Grid Transformation Program are scheduled to be in service by 2030.

Where is the Program located?

The Northern Missouri Grid Transformation Program is a portfolio of new energy projects that includes more than 255 miles of new 345 kV transmission lines developed in two phases across northern Missouri.

Phase 1 includes the Fairport-Denny-Iowa/Missouri Border (FDIM) Project and the Maywood-Mississippi River Crossing (MMRX) Project. The FDIM Project is located in Worth, Gentry and DeKalb counties. 

Phase 2 of the Program includes the Denny-Zachary-Thomas Hill-Maywood (DZTM) Project. This project is in ten counties including DeKalb, Grundy, Daviess, Sullivan, Adair, Knox, Lewis, Marion, Macon and Randolph counties. 

How do you determine the study area for the program?

A preliminary routing review of the Program was conducted, and various constraints and sensitivities were identified. During our public engagement in 2024, our team will receive input from the communities on the Study Areas of the program where these new corridors are needed. All comments will be reviewed to further develop the proposed route that adheres to our routing criteria opportunities, sensitivities, statutory requirements and technical guidelines. Dependent upon this routing criteria process and the community's input, we anticipate filing a Phase 1 final proposed route in summer 2024 and a Phase 2 final proposed route in late 2024 with the Missouri Public Service Commission (MoPSC).

Public and Stakeholder Involvement

How is the Program team working with the communities within the Program Area?

We started by identifying all communities in the region and all other government units such as school districts and soil and water conservation districts. We also identified other organizations that may have an interest in the Program Area, including U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, Missouri Department of Natural Resources, State Historic Preservation Office and others. Our team is also available to meet individually with community officials or organizations, as requested.

How can I provide comments?

We appreciate your participation. We not only want your comments, but we also encourage them. You can submit questions or comments on the website. We also have a dedicated hotline: 1.833.799.1633. If you leave a message, a representative from our team will return your call. You can also send us an email at connect@AmerenGridMO.com.

Environmental and Agency Coordination

Is the Program coordinating environmental planning with any agencies or organizations?

Ameren Missouri will coordinate with various environmental related agencies, including the U.S. Army Corps of Engineers, U.S. Fish and Wildlife Service, Missouri Department of Conservation, State Historic Preservation Office and others. We also invite these agencies to attend our meetings. Ameren Missouri is committed to environmental management and sustainability. Learn more at Ameren.com/Biodiversity.

Will the Project impact birds?

Ameren uses an avian-safe structure design and flight diverters where necessary as part of our corporate Avian Protection Plan to minimize impacts to migratory birds.

Will the Project impact threatened or endangered species?

As a part of Ameren’s evaluation of potential routes, the minimization of environmental impacts – including those to threatened and endangered species – is a priority. Ameren will prioritize routes that will avoid or minimize impacts to threatened and endangered species. Ameren will work with state and federal agencies to identify potential impacts and compensate/mitigate for such occurrences as required for any unavoidable impacts. In most cases, Ameren can avoid or substantially minimize impacts to most species through implementation of various conservation measures. Many threatened and endangered species inhabit our transmission corridors after construction, especially where native vegetation and habitats are established as part of the restoration and ongoing maintenance efforts throughout the life of the project.

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Reliability

Growing Opportunities

Energy Sources

Increased Capacity

Lower Costs