Ameren on Jan. 6 said that its wholly owned subsidiary, Ameren Transmission Company of Illinois (ATXI), has completed and energized the $267m, 345-kV Mark Twain Transmission Project, which involves a substation and a 96-mile transmission line that travels west from Palmyra to Kirksville, Mo., then north to the Iowa border.
The project, which includes the Zachary substation in Adair County, Mo., was placed into service as expected on Dec. 19, 2019, the company said.
As noted on the project’s webpage, the line’s route runs through Adair, Knox, Lewis, Marion, and Schuyler counties in Missouri. Nearly 100% of the line is co-located on existing rights of way, the site noted, adding that the route will co-locate on existing right of way (ROW) on Northeast Missouri Electric Power Cooperative’s 161-kV line between Palmyra and Kirksville and Ameren Missouri’s 161-kV line from Kirksville to the Iowa border.
The project provides such local and regional benefits as improved energy grid reliability, increased transmission capacity, and greater access to lower cost energy, including wind energy, Ameren said in its statement.
The Missouri Public Service Commission in January 2018 granted ATXI a certificate of convenience and necessity for the project, which was approved in 2011 by the Midcontinent ISO (MISO), Ameren said.
The company noted that the project is part of the multi-state group of transmission projects known as Multi-Value Projects (MVPs) that are being developed by transmission owners in MISO to improve and strengthen the regional energy grid. Other ATXI MVPs include the Spoon River Project in Illinois, which was completed in February 2018, and the Illinois Rivers Project, which is anticipated to be in service in December, the company said.
According to the Spoon River Transmission Line Project webpage, the project involves a 44-mile, 345-kV line between Galesburg and Peoria.
According to the Illinois Rivers Project webpage, ATXI is building the 345-kV transmission line from Palmyra to Sugar Creek, Ind. Four towers are required for a river crossing, with two on the east side and two on the west side of the Illinois River, the site noted, adding that the Meredosia-Ipava river crossing towers will reach a height of 486 feet with a span of more than 3,700 feet between the large towers and 7,300 feet between the dead end towers. The 375-mile project is estimated to cost $1.4bn, the site noted.