Missouri PSC grants approval, with conditions, to ATXI for Mark Twain project

The Missouri Public Service Commission (PSC), in a report and order issued on April 27, granted Ameren Transmission Company of Illinois’ (ATXI) application for a certificate of convenience and necessity to build the Mark Twain Transmission Project, subject to certain conditions.

“ATXI has shown a need for Mark Twain, qualifications to own and operate it, the financial ability to build it, the economic feasibility of building it, and the public interest that would be served by building it,” the PSC said in its order, which has an effective date of May 27.

As noted in the order, ATXI in May 2015 applied to the PSC for the certificate to build the transmission line and associated facilities in the counties of Schulyer, Adair, Knox, Shelby and Marion in Missouri. The project would consist of about 95 miles of new 345-kV electric transmission line, a 2.2-mile, 161-kV connector line, a substation and related facilities.

The proposed 345-kV line will be routed from the new Maywood switching station near Palmyra, Mo., through Marion, Shelby, Knox and Adair counties to the new Zachary substation, located near Kirksville, Mo., and then continuing north through Adair and Schuyler counties to the Iowa border, the PSC added.

The 345-kV line will primarily consist of single-shaft, self-supported steel poles, 90 feet to 130 feet in height, within a 150-foot right of way (ROW). The PSC also said that the new 2.2-mile, 161-kV line will connect the Zachary substation with the existing Adair substation.

The PSC said that ATXI’s expected total cost of the project along that route is about $224m:

  • Two 345-kV lines at a cost of $192.5m
  • The Zachary substation at a cost of $27m
  • A connector line between the Zachary and Adair substations at a cost of $2.6m
  • Modifications at the Adair substation at a cost of $1.9m

According to the company’s website, the project is scheduled to be in service in 2018.

The project stems from a study conducted by the Midcontinent ISO (MISO), the PSC said, noting that MISO in 2008 began an extensive study of the regional electric transmission grid to identify transmission needs and develop a planning process to build transmission projects to meet those needs. MISO in 2011 identified a “multi-value portfolio” (MVP) of 17 transmission projects that would increase the overall reliability and efficiency of the regional transmission grid, meet public policy demands for renewable energy, and provide economic benefits in excess of the portfolio costs, the PSC said. The Mark Twain project consists of the Missouri portion of two of those MVP projects, MVP #7 and nearly all of #8 included in the MISO Transmission Expansion Plan in accordance with MISO’s FERC-approved tariff.

The PSC also noted that the costs to build and operate MVP projects such as the Mark Twain project, are reflected in transmission charges to load-serving entities in MISO’s footprint, which in turn reflect charges they collect in their retail revenue requirements. Missouri represents just under 8% of the load in MISO, which means that less than 8% of the transmission charges arising from the project will be paid by Ameren Missouri and other wholesale load-serving entities in Missouri, the PSC said. The remainder will be paid for by other load-serving entities across the MISO footprint, the PSC said.

MISO and its board of directors determined that the 17 projects that comprise the MVP were necessary to facilitate the delivery of renewable energy, resolve numerous reliability issues, reduce transmission line losses, and provide economic and efficiency benefits to customers throughout the MISO footprint.

The PSC also said that the benefits of the Mark Twain project are proven by multiple cost-benefit analyses, including one that was conducted by MISO as part of the MVP approval process, in which MISO evaluated the economics of the overall MVP portfolio under four scenarios.

The PSC noted that the project will help Missouri meet its renewable energy obligations, even if no additional wind generation is developed in the relevant portions of the state. Also, the project will provide an additional means by which electricity may be delivered into and from Missouri, particularly from areas rich in wind energy.

The PSC added that while Ameren Missouri anticipates that its current resources will not allow it to meet its renewable energy standards requirements after 2018, the company plans to acquire 400 MW of wind capacity, starting in 2019, and have it in place by 2026. The Mark Twain project could help enable Ameren Missouri to comply with its renewable energy standards requirements and with the U.S. Environmental Protection Agency’s (EPA) Clean Power Plan, the PSC said.

Discussing reliability, the PSC said the addition of the 345-kV lines and step down transformer at West Adair is especially effective in resolving 161-kV line overloads on the lines out of West Adair and preventing the loss of the generation at West Adair during certain NERC “Category C” events. The project will increase reliability in the northeast portion of Missouri, including Kirksville, the PSC said.

On access to wind zones, the PSC noted that there is significant potential for wind development in north central and northeast Missouri, including in the Adair Wind Zone. The characteristics of that wind zone, combined with the project’s proximity to it and the ability to transmit energy generated within the zone, create the potential for up to 1,347 MW of wind generation to be developed in northeast Missouri, the PSC said.

Another reason the additional wind generation is expected is its low cost relative to other renewable resources, the PSC said. Looking at the levelized cost of energy, and based on current technologies, wind-generated electricity is lower cost than solar-generated electricity. Furthermore, the PSC added, the production tax credit (PTC), originally scheduled to expire at the end of this year, was extended until 2019, and that credit encourages future wind development by providing a tax credit to wind developers for a generation project started by the end of 2019.

MISO recently added a 400 MW wind generation project into its queue, which is proposed to connect to the completed Mark Twain project 345-kV line in Schuyler County, the PSC said.

Discussing the environment, the PSC noted that after consulting with the Missouri Department of Conservation, the Missouri Department of Natural Resources and the U.S. Fish and Wildlife Service, ATXI made adjustments to the proposed routes under consideration in order to minimize stream crossings, wetlands, and other route considerations.

Among other things, the PSC said that the certificate is contingent upon ATXI providing certified copies of county assents for the project from Marion, Shelby, Knox, Adair and Schuyler counties. Also, the plans and specifications for construction of the project that ATXI is developing are to be filed with the PSC.

In addition, the PSC said, throughout the ROW acquisition process, ATXI will use all reasonable efforts to abide by the depicted route on each of the 377 parcels identified as of the filing of its application as parcels over which an easement will be required, but will be allowed to deviate from the depicted route within one of the 377 parcels in two scenarios. For instance, ATXI may deviate from the depicted route on a particular parcel if ATXI and the landowner agree, upon request of the landowner and ATXI’s agreement with the request.

ATXI is a wholly owned subsidiary of Ameren (NYSE:AEE).

About Corina Rivera-Linares 3286 Articles
Corina Rivera-Linares was TransmissionHub’s chief editor until August 2021, as well as part of the team that established TransmissionHub in 2011. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial from 2005 to 2011. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines.