The $1bn project involves construction of around 400 mile, 345kV transmission line that crosses Mississippi River near Quincy, and continuing east across Illinois to the Indiana border.

ATXI received certificate of public convenience and necessity from the ICC for seven of the nine proposed segments on the route and three of nine proposed bulk substations.

The company will now move forward on the approved portions of the project and anticipates starting right-of-way acquisitions immediately, while full range of construction activities will be in 2014.

ATXI president and CEO Maureen Borkowski said, "This project will help fuel the Illinois economy and provide customers access to a variety of energy sources, including wind energy."

Earlier, Federal Energy Regulatory Commission and Midcontinent Independent System Operator approved the Illinois Rivers transmission project.