MISO Picks Ameren, NextEra and Dairyland for a $1.23 Billion, 187-Mile 765 kV Iowa Line Due June 2034
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Marin Holt
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- MISO estimated cost: $1.23 billion
- New 765 kV line: 187 miles
- 765 kV in-service date: June 1, 2034
- Ownership: 42.5% ATXI, 42.5% GridLiance, 15% Dairyland
The Midcontinent Independent System Operator has selected a consortium of Ameren Transmission Company of Illinois, GridLiance Heartland and Dairyland Power Cooperative to build the EASL transmission project in southern Iowa. The companies announced the award on October 22, 2026. The MISO estimated cost for the project is approximately $1.23 billion. The package includes one new 765 kV transmission line of about 187 miles and a new 345/765 kV substation named East Adair. It also includes two new 345 kV lines totaling about 22 miles. The 765 kV scope has an expected in-service date of June 1, 2034. The 345 kV scope is due June 1, 2032.
Ameren Transmission Company of Illinois, or ATXI, is a subsidiary of Ameren Corporation. GridLiance Heartland is a subsidiary of NextEra Energy Transmission. ATXI and GridLiance will lead development. ATXI, GridLiance and Dairyland will have ownership stakes in the project of 42.5%, 42.5% and 15%, respectively, once it is in service. The release says MISO chose the group because its proposal offered the best overall value on design, execution capabilities and regulatory experience.
The 765 kV line will run north from the new East Adair substation in southern Iowa to the Minnesota/Iowa state line. One 345 kV line will run south from East Adair to a dead end east of York Avenue. The other will run north from East Adair to the existing Arbor Hill substation, also in southern Iowa. EASL stands for East Adair, Minnesota/Iowa State Line, Arbor Hill and York Avenue.
EASL is one of the 24 projects in the MISO Long Range Transmission Planning Tranche 2.1 portfolio. The MISO board approved that portfolio on December 12, 2024. The MISO RFP release schedule lists EASL at an estimated $1,226.3 million in 2024 dollars. The request for proposals went out on December 11, 2025. Bids were due May 26, 2026. MISO revised the EASL entry twice before that. A July 2025 revision corrected its in-service dates. A December 2025 revision corrected its proposal deadline. The same schedule lists a second Iowa competitive project that also ends at East Adair, called MARS, with bids due May 11, 2026 and a larger estimate than EASL. The October 22 release does not mention it.
The same three companies won the MISO selection in May 2026 for two Illinois 765 kV projects, STIW and WIIL, together with the Illinois Municipal Electric Agency. In that award, STIW covers about 149 miles at a MISO estimated cost of $940 million. WIIL covers 88 miles plus a 765/345 kV substation at $718 million. Both target 2034. MISO describes its competitive process as applying to eligible multi-value projects in states without right-of-first-refusal clauses. It accepts bids only from certified Qualified Transmission Developers.
Why It Matters
EASL is the Iowa leg of the 765 kV backbone that Tranche 2.1 is meant to build across the Midwest. With this award, one consortium now holds three competitive segments of that backbone, from central Illinois west into Iowa and north to the Minnesota line. The release does not say how many developers bid. It gives no cost cap or cost-containment term beyond the MISO estimate.
The schedule carries more weight than the award. The 345 kV pieces are due in 2032 and the 765 kV line in 2034, nearly ten years after the portfolio approval. The Illinois legs awarded in May also target 2034. The estimate is in 2024 dollars. It has not yet passed through routing, state regulatory review or procurement. Ameren, NextEra and Dairyland said regulatory review and stakeholder engagement come next. Readers tracking the cost of the 765 kV build-out should watch the first state filing for the number the developers commit to.
Critical Perspective
Every number in this story comes from the developers or from MISO planning documents. The $1.23 billion is a MISO estimate in 2024 dollars, not a bid price. The release discloses no cost cap, no cost-containment commitment and no count of competing proposals, so there is no way to judge how much value the competition produced. The schedule has already moved once: MISO corrected the EASL entry in July 2025 and again in December 2025 before any developer was chosen, and the 765 kV line is now not due until June 2034. One consortium now holds three competitive segments of the Tranche 2.1 backbone across Illinois and Iowa, which concentrates execution risk on a single group of companies for most of a decade. No Iowa regulator has seen a filing yet, and the route north from East Adair to the Minnesota line has no approved corridor. What will the first state filing show as the committed cost, and how far will it sit from $1,226.3 million?
Sources
- Ameren / NextEra Energy Transmission / Dairyland via PR Newswire: MISO selects consortium of Ameren, GridLiance, Dairyland to deliver foundational energy grid project in Iowa (Oct 22, 2026)
- Seeking Alpha via TradingView: Consortium led by Ameren, NextEra selected by MISO to build $1.2B Iowa transmission project (Oct 22, 2026)
- MISO: LRTP Tranche 2.1 Competitive Transmission Projects, Schedule of Planned Release Dates for Each RFP (posted Dec 11, 2025)
- Ameren: MISO selects consortium of Ameren, GridLiance, Dairyland, Illinois Municipal Electric Agency to deliver major grid-bolstering projects in Illinois (May 19, 2026)
- MISO: Competitive Transmission Administration (program page)
