The new lines will be co-located alongside existing Ameren corridors across 13 central Illinois counties—from the Mississippi River at Quincy through the Peoria metro area to Tazewell County. 

Eight substations—three new facilities at Camp Point, Kenney and Piper City and five rebuilt or expanded stations in Brown County, Pontiac, Gibson City, Iroquois County and Peoria—will be tied into the network, with upgraded communications and supervisory control and data acquisition systems to monitor and control equipment remotely.

“At a time when the Midwest faces a persistent shortage of the electricity needed to meet rising demand, this vital project will provide energy access and certainty for businesses and residential growth,” said Shawn Schukar, chairman and president of Ameren Transmission Co. of Illinois, in a company release.

Ameren filed its joint petition in January 2024 (ICC Docket 24-0088), submitting detailed routing maps, a preliminary cost-benefit analysis and wetland assessment summaries. Commission staff issued 25 data requests, probing right-of-way acquisition plans, load-flow modeling, environmental mitigations and coordination with third-party infrastructure owners. 

Map courtesy of Ameren Illinois

Public hearings in Springfield in May 2024 drew testimony from private-landowner groups and individual witnesses who suggested alignment tweaks. However, commission staff, along with Ameren engineers, said such deviations would raise costs by 2%–4% or require new substation work, and approved the original alignment as “necessary to maintain reliability and support future load growth.”

Several commenters raised land‐use and health concerns: James Williams, whose Iroquois County farm borders a 138-kV line, urged the commission to “use existing rights-of-way” rather than take new farmland. Matthew Hadsall of Peoria County warned, “My greatest concern as a father of seven children is their health living close to high-voltage power lines,” and asked for a quarter-mile residential setback.

Ameren responded that “existing environmental controls and species-protection measures meet all state and federal requirements” and that package deviations could increase costs or complicate substation design.

Pooled analyses have found that children in homes with average extremely low-frequency magnetic fields above 0.3–0.4 µT—levels common within about 100 m of major transmission lines—face roughly twice the risk of childhood leukemia, and the International Agency for Research on Cancer classifies these fields as possibly carcinogenic to humans (Group 2B). 

Still, leading health agencies maintain that routine residential exposures pose little substantiated risk: the World Health Organization reports “no substantive health issues” at environmental field levels, and the U.S. Environmental Protection Agency notes that studies have not consistently demonstrated adverse effects at typical exposure levels.