MISO selects consortium of Ameren, GridLiance, Dairyland to deliver foundational energy grid project in Iowa

ST. LOUIS and JUNO BEACH, Fla., Oct. 22, 2026 /PRNewswire/ -- The Midcontinent Independent System Operator (MISO) has selected a consortium of Ameren Transmission Company of Illinois (ATXI), a subsidiary of Ameren Corporation (NYSE: AEE); GridLiance Heartland, LLC, a subsidiary of NextEra Energy Transmission, LLC; and Dairyland Power Cooperative to develop, build, operate and maintain a major transmission project in Iowa. ATXI and GridLiance will lead the development of this project and own it jointly with Dairyland once it is placed in service.

The East Adair – Minnesota/Iowa State Line – Arbor Hill – York Avenue (EASL) project is foundational to a new 765-kilovolt (kV) backbone that will deliver safe, reliable and affordable energy to Midwest communities.

MISO selected the consortium through a competitive process after determining that its proposal offered the best overall value, based on its design, execution capabilities, regulatory experience and other key factors.

The total MISO estimated cost for this competitive transmission project is approximately $1.23 billion. ATXI, GridLiance, and Dairyland will have ownership stakes in the project of 42.5%, 42.5%, and 15%, respectively.

"MISO's selection reflects our commitment to delivering value for customers," said Shawn Schukar, chairman and president of ATXI. "We focused on developing a proposal that is reliable, economical and able to be built on time. Now, we are excited to deliver this project and see it benefit Midwest communities for decades to come."

"This win reflects the collective strength of our transmission experience and cost-competitive approach," said Matt Valle, president of NextEra Energy Transmission, LLC. "We're proud to partner with Ameren and Dairyland to deliver critical infrastructure to affordably modernize the electric grid that powers Iowa's growing energy needs and economy."

"A strong transmission system is essential to delivering the reliable electricity our communities depend on today while preparing for the needs of tomorrow," said Brent Ridge, president and CEO of Dairyland Power Cooperative. "This project will strengthen the regional grid, improve resiliency and create greater flexibility to accommodate future energy resources and economic growth."

The EASL project includes the construction of one new 765-kV transmission line spanning approximately 187 miles, one 345/765-kV substation named East Adair, and two new 345-kV transmission lines spanning approximately 22 miles in total.

The 765-kV line will run north from the new East Adair Substation in southern Iowa to the Minnesota/Iowa state line. The first 345-kV transmission line will run south from East Adair and connect to Deadend East of York Avenue. The second 345-kV transmission line will run north from East Adair and connect to the existing Arbor Hill Substation, which is also in southern Iowa.

EASL is a competitive project in MISO's Long Range Transmission Planning Tranche 2.1 Portfolio, which was originally approved in December 2024. The 765-kV scope of the project has an expected in-service date of June 1, 2034, while the 345-kV scope has an expected in-service date of June 1, 2032. The project will undergo the regulatory review process and thorough stakeholder and community engagement.

ATXI, GridLiance, and Dairyland were also selected earlier this year, along with the Illinois Municipal Electric Agency, to deliver the Sub T – Iowa/Illinois State Line – Woodford County (STIW) and Woodford County – Illinois/Indiana State Line (WIIL) projects. Those earlier projects are also part of the Tranche 2.1 Portfolio.

About Ameren Corporation
St. Louis-based Ameren Corporation powers the quality of life for 2.5 million electric customers and more than 900,000 natural gas customers in a 64,000-square-mile area through its Ameren Missouri and Ameren Illinois rate-regulated utility subsidiaries. Ameren Illinois provides electric transmission and distribution services and natural gas distribution services. Ameren Missouri provides electric generation, transmission and distribution services, as well as natural gas distribution services. Ameren Transmission Company of Illinois develops, owns and operates rate-regulated regional electric transmission projects in the Midcontinent Independent System Operator, Inc. For more information, visit Ameren.com, or follow us at @AmerenCorp, Facebook.com/AmerenCorp, or LinkedIn.com/company/Ameren.

About NextEra Energy Transmission
NextEra Energy Transmission, LLC is North America's leading competitive transmission company. With more than 3,200 miles of transmission lines in operation and development in 19 states and Canada, the company is strengthening and modernizing the electric grid to meet the country's growing energy needs. NextEra Energy Transmission owns, develops, finances, constructs, operates and maintains transmission assets across the continent. The company operates through its regional subsidiaries to integrate diverse energy sources. NextEra Energy Transmission, LLC is a subsidiary of Juno Beach, Florida-based NextEra Energy, Inc. For more information, visit www.NextEraEnergyTransmission.com. 

About Dairyland Power Cooperative
Founded in 1941, Dairyland provides the wholesale electrical requirements and other services for 24 Class A member distribution cooperatives, 2 Class B members and 27 municipal utilities in the Upper Midwest. In turn, these cooperatives and municipals meet the energy needs of over 800,000 people. Dairyland delivers electricity over 3,700 miles of transmission lines and 400 distribution substations located throughout the system's 44,500 square mile service area.

SOURCE Ameren Corporation