Southern Illinois Reliability Project
Ameren Illinois has completed and energized the Southern Illinois Reliability Project. The 140 miles of rebuilt, 345-kV line is providing greater energy reliability, more access to renewable energy and has increased transmission capacity across seven counties in southern Illinois.
About the Project

The Southern Illinois Reliability Project reconstructed the existing 230-kV transmission line from Cahokia to Joppa, originally built in the 1950s. Customers in St. Clair, Washington, Perry, Franklin, Williamson, Johnson, and Massac counties are now benefiting from the infrastructure upgrades.

The upgraded transmission line is improving system reliability while opening pathways for clean energy to be distributed to the region. It is also increasing transmission capacity to meet the area's growth needs. Crews completed the Southern Illinois Reliability Project in December 2023. Land restoration efforts were completed in the spring of 2024.

Completion Date: December 2023
Type: 340-kV transmission line
Length: 140 miles across 7 counties

Community Benefits

Reliability

Rebuilding aging infrastructure and enhancing our energy system to improve reliability

Renewable Energy

Promoting access to renewable energy resources like solar

Capacity

Increasing transmission capacity
Contact Us

Phone: 618.808.3093

Email: SouthernILReliability@ameren.com

Mail: Southern Illinois Reliability Project c/o Volkert, 1500 Eastport Plaza Drive, Suite 200, Collinsville, IL 62034