The Illinois Commerce Commission (ICC) on Thursday approved plans by utility Ameren Corp. to construct a $1.1-billion, 380-mile high-voltage power line across sections of central Illinois.

Known as the Illinois Rivers Transmission Project, the line will be the largest of its kind in Illinois history as well as the largest undertaken by St. Louis-based Ameren. The utility says the line will promote delivery of low-cost power while improving the reliability and efficiency of the power grid.

The project also “will provide Illinois customers greater access to alternative lower-cost energy sources, including wind energy,” says Maureen Borkowski, CEO with Ameren subsidiary Ameren Transmission Co. Illinois (AXTI)

In August, ICC approved select project routes and substations for the project, and on Thursday resolved remaining routes and substation locations. The 345,000-volt line, which includes steel poles with a single shaft, will originate in Palmyra, Mo., crossing the Mississippi River at Quincy, Ill. From there, it will extend east past Meredosia, Pawnee, Pana, Mt. Zion and Kansas, terminating in Sugar Creek, Ind., with additional lines extending from Meredosia to Ipava, Ill., and between Sidney and Rising substations near Champaign, Ill.

Following August's decision, AXTI began executing portions of the project with final route approval, including surveying and negotiations with landowners to secure 150-foot-wide easements. Substation construction currently is under way. Line construction is expected to begin later this year.

The project previously received approvals from the Federal Energy Regulatory Commission and  Midcontinent Independent System Operator Inc., a regional transmission organization serving a 15-state region and Canadian province Manitoba.