Ameren’s unit in the US state of Illinois has secured regulatory approval to construct 380 miles of new and upgraded high-voltage transmission lines as part of a $1.6bn project.
The Illinois Commerce Commission has approved the proposed route via a certificate of public convenience and necessity.
Known as the Central Illinois Grid Transformation Program (CIGTP), the project comprises three new substations and upgrades to existing substations.
The project will run from Iowa's border through 13 counties: Adams, Brown, Champaign, Ford, Fulton, Hancock, Iroquois, McDonough, McLean, Morgan, Peoria, Pike,and Tazewell.
Construction will begin in the second half of 2025 and will be completed in 2029.
Ameren Transmission Company of Illinois chairman and president Shawn Schukar stated: "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.
"Adding system capacity and increasing access to energy resources will improve reliability, boost economic development and help keep bills affordable for energy consumers in Illinois."
The majority of the work will be carried out along existing infrastructure corridors to minimise land use.
By replacing ageing infrastructure and increasing transmission capacity, CIGTP will ensure a consistent energy supply and facilitate greater access to diverse energy sources for communities within central Illinois.
CIGTP project manager Thomas Pauk said: "We look forward to working with local communities to deliver these benefits to our customers, as we have been for over 100 years.
"When we increase system capacity, everyone wins. Opening new energy pathways promotes lower costs in the future and helps keep customer rates affordable."
The initiative will lower supply costs by creating new channels for delivering energy efficiently to millions within Ameren's service territory.
Ameren Illinois regulatory policy and energy supply vice-president Matt Tomc stated: "MISO [the Midcontinent Independent System Operator] is advancing projects that directly address the energy supply challenges that are driving up those costs for our customers.
"By expanding transmission capacity and improving access to a range of energy resources, these investments will help stabilise market prices and support our ongoing efforts to keep energy affordable and reliable for the communities we serve."
In June 2025, Ameren Missouri submitted a proposal to the Missouri Public Service Commission for the construction of an 800MW simple-cycle natural gas power facility in conjunction with its first significant battery storage system.
