Ameren Transmission Company of Illinois has started work on the $250 million Mark Twain Transmission Project, a 96-mile, 345-kilovolt transmission line in northeast Missouri. The company also broke ground on the Zachary Substation, which is also part of the overall project.

Much of the transmission line will be co-located on existing rights of way that include Northeast Missouri Electric Power Cooperative's 161 kV line and Ameren Missouri's 161 kV line to the Iowa border.

The anticipated in-service date is December 2019.

Ameren Missouri said on May 21 that it plans to buy a 400-megawatt wind farm in northeast Missouri to be built by Terra-Gen. Groundbreaking is expected in summer 2019. The wind farm is enabled in part by the expanded transmission capacity made possible by the Mark Twain Transmission Project.