Approval of Long-Range Transmission Projects in Illinois Will Deliver Reliable, Resilient Energy Future

SPRINGFIELD, IL. (July 2, 2025) – Today the Illinois Commerce Commission (ICC) granted final approval of Ameren Transmission Company of Illinois (ATXI) and Ameren Illinois’s Central Illinois Grid Transformation Program. The program is a landmark effort to modernize and expand Illinois’ energy grid with 380 miles of new and expanded transmission lines, a vast majority of which will be rebuilt along existing corridors and co-located with existing facilities. Clean Grid Alliance (CGA), Environmental Defense Fund (EDF), and Illinois Citizens Utility Board (CUB) celebrated the decision, which will enable the delivery of affordable, reliable energy across the state.

The ICC approved the certificate of public convenience and necessity for the 380-mile program that will connect the energy grid across Illinois from Indiana to Iowa and Missouri, improving reliability and enabling access to low-cost renewable energy resources. The program is a significant part of the Midcontinent Independent System Operator’s (MISO) Long-Range Transmission Plan (LRTP) Tranche 1 project that spans across the Upper Midwest, and it is expected to provide up to $2.8 billion in financial benefits for the state of Illinois over the next 20 years.

“Infrastructure projects like the Central Illinois Grid Transformation Program are critical to ensuring low-cost, reliable energy can flow freely across the region,” said Elizabeth Wheeler, Senior Counsel and Director of Regulatory Advocacy at Clean Grid Alliance. “Modernizing our electric grid with new and upgraded transmission lines is absolutely necessary to support a secure economic future for Illinois.”

"The Central Illinois Grid Transformation Program will deliver a more reliable, affordable energy future for Illinois residents," said Curt Stokes, Senior Attorney at Environmental Defense Fund. "This project is crucial for grid reliability, unlocking access to affordable renewable energy and delivering billions in benefits from lower carbon emissions." 

“We thank the Illinois Commerce Commission for approving this transmission program, which will help advance Illinois' goal of securing clean and affordable energy for its residents," said Jim Chilsen, Communications Director of the Citizens Utility Board. “Smart, cost-effective transmission planning is critical to the clean energy transition, and an absolute must to help Illinois achieve a clean, affordable energy future for all electric customers.” 

The Tranche 1 portfolio of LRTP projects was approved by MISO in July, 2022 to provide $37 billion in regional economic benefits over 20 years and improve grid reliability and integration of new, low-cost renewable energy resources. As "least-regrets" projects, the Tranche 1 transmission lines are foundational to solving long-standing reliability and efficiency concerns along the regional electricity grid.