Iowa Utilities Commission OKs ITC request to rebuild Eastern Iowa transmission lines

Iowa commissioners gave permission this week for ITC Midwest to move forward with plans to build electric transmission lines in Eastern Iowa, one piece of a multimillion-dollar portfolio of projects intended to improve power grid reliability and resilience across the Midwest.

On Monday, the Iowa Utilities Commission approved Cedar Rapids-based ITC Midwest’s request to add a 345-kilovolt (kV) line to an existing 161-kV line through Marshall, Tama, Benton and Linn counties.

The line, whose cost is estimated at $221 million, is part of a batch of transmission projects — called Tranche 1 — that was approved by the Midcontinent Independent System Operator board in 2022.

MISO, as it is called, manages energy on the power grid in Iowa and 14 other states, as well as a Canadian province.

The total cost of Tranche 1 was estimated at $10.3 billion.

Rod Pritchard, spokesperson for ITC Midwest, said the project approved Monday will include rebuilding an existing 161-kV line to construct a new double circuit 345-kV line on the same right of way in Tama and Benton counties. The current structures holding up the lines will come down and will be rebuilt to support the double circuit, which will hold two transmission lines on one structure.

Pritchard said using a double circuit means there will be fewer structures holding up the transmission lines per mile.

“The existing structures come down, the existing line comes down, but then it's rebuilt as a 345-kV and 161-kV double circuit,” he said.

The structure’s poles will be about 125 to 170 feet tall after they are installed and will be spaced about 800 to 1,200 feet apart.

The project, which spans parts of Linn, Tama, Benton and Marshall counties, is called the Morgan Valley-Twinkle project.

The transmission line will run from the Twinkle substation on the east side of Marshalltown in Marshall County, to the Morgan Valley Substation near Fairfax in Linn County. Only about 3.5 miles of the line will be in Linn County.

A 115-kV transmission line that runs through part of Benton County and is on the same route as the 345-kV line will be decommissioned and removed through this project.

The 345-kV transmission line will span about 60.58 miles across Marshall, Tama, Benton and Linn counties, whereas the 161-kV transmission line spans approximately 33.76 miles throughout Marshall, Tama and Benton counties.

The project — and the larger portfolio of projects approved by MISO — is intended to make the power grid more reliable. That extra reliability lowers the risk of controlled power outages in MISO’s region, and will reduce power overloads.

ITC Midwest said the rebuilt lines in the project approved this week are needed to keep “responding to the needs of the changing energy landscape.”

“ITC Midwest looks forward to constructing the Morgan Valley-Twinkle transmission line and placing it in service to provide numerous benefits and drive value for electricity consumers locally and regionally,” Pritchard said. “When completed, this line will improve system reliability, enhance grid resilience to better withstand extreme weather, expand access to diverse generation resources and improve distribution of lower-cost energy resources.”

Eminent domain will be used in Tama County

ITC sought and was granted permission to use eminent domain for one parcel of land in Tama County. The company called it “necessary for public use.”

The commission stated that the project is “necessary to serve a public use and represents a reasonable relationship to an overall plan of transmitting electricity in the public interest consistent with Iowa Code chapter 478.”

ITC Midwest has two years to construct the electric transmission line.

“If construction of the project is not at least commenced within that time, the company can petition the Commission for an extension of time to begin construction,” Pritchard said.

The company has been granted approval through Nov. 24, 2050, unless “sooner revoked or modified.”

ITC Midwest operates more than 6,600 circuit miles of transmission lines in Iowa, Minnesota, Illinois, Missouri and Wisconsin.

Olivia Cohen covers energy and environment for The Gazette and is a corps member with Report for America, a national service program that places journalists in local newsrooms to report on under-covered issues. She is also a contributing writer for the Ag and Water Desk, an independent journalism collaborative focusing on the Mississippi River Basin.

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Comments: olivia.cohen@thegazette.com