MISO awards $1.23 billion Iowa transmission project to Ameren, GridLiance, and Dairyland Power Cooperative consortium
Three companies will jointly build one of the Midwest’s most significant new power lines in years. On October 22, 2026, MISO selected a consortium of Ameren Transmission Company of Illinois, GridLiance Heartland, and Dairyland Power Cooperative to develop, build, operate, and maintain the East Adair – Minnesota/Iowa State Line – Arbor Hill – York Avenue (EASL) transmission project in Iowa — a high-voltage infrastructure effort estimated at approximately $1.23 billion.
MISO selects consortium through competitive process
MISO didn’t just hand this project to the first bidder. The selection followed a competitive review where the grid operator evaluated proposals based on design quality, execution capabilities, regulatory experience, and overall value to customers.
The winning team — Ameren Transmission Company of Illinois (ATXI), GridLiance Heartland, and Dairyland Power Cooperative — will share ownership once the project enters service. ATXI and GridLiance each hold a 42.5% stake, while Dairyland takes the remaining 15%. Both ATXI and GridLiance will lead development and construction.
The EASL project brings together a $1.23 billion investment, three experienced transmission partners, and a clear mandate from MISO to strengthen the regional grid.
“We focused on developing a proposal that is reliable, economical and able to be built on time,” said Shawn Schukar, chairman and president of ATXI. Matt Valle, president of NextEra Energy Transmission, added that the win reflects the consortium’s “transmission experience and cost-competitive approach.”
What the EASL project will build
The centerpiece is a single 765-kV transmission line stretching approximately 187 miles — running north from a newly constructed substation called East Adair in southern Iowa all the way to the Minnesota/Iowa state line.
East Adair Substation is a key piece of the build. Operating at both 345-kV and 765-kV, it serves as a hub connecting the new high-voltage backbone to existing regional infrastructure. Two additional 345-kV lines, totaling roughly 22 miles, branch off from East Adair: one heads south to connect with Deadend East of York Avenue, the other runs north to tie into the existing Arbor Hill Substation, also in southern Iowa.
Together, these components form part of what MISO describes as a new 765-kV backbone — a foundational layer of high-capacity infrastructure built to move large volumes of power reliably and affordably across the Midwest. The EASL project is part of MISO’s Long Range Transmission Planning Tranche 2.1 Portfolio, which the grid operator originally approved in December 2024.
Expected in-service dates and regulatory steps ahead
The project rolls out in two phases. The 345-kV scope — covering the two shorter transmission lines and the East Adair Substation — carries an expected in-service date of June 1, 2032. The larger 765-kV line is scheduled to come online by June 1, 2034.
Before any construction begins, the project has to clear regulatory review and move through stakeholder and community engagement processes, both standard for large transmission builds at this scale. Consortium executives were direct about their intentions: their proposal was designed to be reliable, economical, and deliverable on schedule — language that signals the team is already thinking carefully about the long road from approval to energization.
Context: Tranche 2.1 portfolio and consortium track record
The EASL award isn’t this consortium’s first rodeo in MISO’s Tranche 2.1 buildout. Earlier in 2026, ATXI, GridLiance, and Dairyland — joined by the Illinois Municipal Electric Agency — were selected to deliver two other Tranche 2.1 projects: the Sub T – Iowa/Illinois State Line – Woodford County (STIW) project and the Woodford County – Illinois/Indiana State Line (WIIL) project.
That track record matters. Winning multiple projects within the same portfolio suggests MISO has real confidence in this group’s ability to execute at scale. MISO’s Tranche 2.1 Long Range Transmission Planning Portfolio, approved in December 2024, is a broad effort to modernize and expand the Midwest grid.
Each partner brings solid credentials. NextEra Energy Transmission — GridLiance Heartland’s parent company — operates more than 3,200 miles of transmission lines across 19 states and Canada, making it one of North America’s largest competitive transmission companies. Ameren, based in St. Louis, serves 2.5 million electric customers across Missouri and Illinois. Dairyland Power Cooperative rounds out the team with deep regional roots: founded in 1941, it delivers electricity over 3,700 miles of transmission lines and serves more than 800,000 people across the Upper Midwest.
What this project means for Iowa’s grid
The EASL project brings together a $1.23 billion investment, three experienced transmission partners, and a clear mandate from MISO to strengthen the regional grid. The 765-kV backbone it contributes to isn’t designed just for today’s energy demand — it’s built with the decades ahead in mind, accommodating future resources and supporting economic growth across the region.
The 345-kV components are on track for 2032, with the full high-voltage line to follow by 2034. Regulatory review and community engagement come next. If everything goes to plan, Iowa gains a major piece of transmission infrastructure connecting its southern communities to the broader Midwest power system — and helping keep the lights on reliably for generations to come.
Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.
