MISO Picks Ameren-Led Group for $1.23B, 187-Mile Iowa 765-kV Line
MISO chose Ameren's ATXI, NextEra's GridLiance and Dairyland for the EASL project: a 187-mile 765-kV line due June 2034, still subject to regulatory review.
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MISO's selection covers a 187-mile, 765-kV line in Iowa with an estimated cost of $1.23 billion; regulatory review is still pending.
Illustration (AI-generated)
The Midcontinent Independent System Operator (MISO) has selected a consortium of Ameren Transmission Company of Illinois (ATXI), NextEra Energy's GridLiance Heartland and Dairyland Power Cooperative to build a 187-mile, 765-kilovolt (kV) transmission line in Iowa, a project MISO estimates at about $1.23 billion, according to a joint release dated Oct. 22, 2026.
The East Adair – Minnesota/Iowa State Line – Arbor Hill – York Avenue project, known as EASL, also includes a new 345/765-kV substation named East Adair and two 345-kV lines of about 22 miles in total. The 765-kV line will run north from East Adair in southern Iowa to the Minnesota/Iowa state line. One 345-kV line will run south from East Adair to Deadend East of York Avenue, and the other will run north to the existing Arbor Hill Substation.
ATXI and GridLiance will lead development and, with Dairyland, will own the line once it is in service. The ownership split is 42.5% for ATXI, 42.5% for GridLiance and 15% for Dairyland. MISO chose the group through a competitive process after concluding that its proposal offered the best overall value, citing design, execution capabilities and regulatory experience.
Why it matters for large loads
For anyone planning large loads such as data centers in the upper Midwest, EASL is a long-lead grid addition rather than near-term capacity. The companies describe EASL as foundational to a new 765-kV backbone and say it will accommodate Iowa's growing energy needs. The release does not name data centers as a driver, and Voltgrid has not seen a load forecast tied to this specific project.
The 765-kV scope is expected in service June 1, 2034, and the 345-kV scope June 1, 2032, according to the joint release.
Illustration (AI-generated)
The timeline shows how slowly such capacity arrives. The 345-kV scope has an expected in-service date of June 1, 2032, and the 765-kV scope June 1, 2034, so the 765-kV capacity is about eight years away for developers who need power now.
Where EASL sits in MISO's plan
EASL is a competitive project in MISO's Long Range Transmission Planning Tranche 2.1 Portfolio, which was originally approved in December 2024. The same three companies, together with the Illinois Municipal Electric Agency, were selected earlier this year for two other Tranche 2.1 projects: Sub T – Iowa/Illinois State Line – Woodford County (STIW) and Woodford County – Illinois/Indiana State Line (WIIL), according to the release. Voltgrid News reported earlier on ComEd's GRIT transmission project.
What is not confirmed yet
The selection is not a construction approval. The release says the project will still go through regulatory review and stakeholder and community engagement. A final route and the cost that regulators accept may differ from MISO's $1.23 billion estimate, which is a MISO figure and not a contract price. Who pays, and how the cost is allocated across MISO ratepayers, is not addressed in the release.
