About ATC

Regional upgrades and generation changes

ATC’s role in the nation’s grid

ATC is a Wisconsin-based company that moves energy along the electric power grid in parts of Wisconsin, Michigan, Minnesota and Illinois. We connect all forms of electric generation to the grid. As the electric industry moves toward a variety of generation sources, we are transforming our system to continue delivering energy reliably and safely.

We work directly with the Midcontinent Independent System Operator – the regional grid operator – to help determine the viability, planning and interconnection design for generation projects being proposed within our service area. Our planning and engineering experts then collaborate with our electric utility customers to develop efficiencies and use technologies that interconnect new generation resources to help strengthen the grid.

MISO interactive queue

MISO North
MISO Central
MISO South

Economic benefits of grid development

Regional grid projects driven by MISO span long distances and service areas. Just like an interstate highway system, these lines often cross multiple state lines. Projects that are developed and approved by MISO are cost shared across several states.

Regional grid development is an exceptional value for energy consumers

MISO-approved Multi-Value Projects (MVPS) have cost allocation based on energy withdrawals, which historically has equated to Wisconsin ratepayers covering between 13 to 16 percent of the overall project cost for MVPs. The remainder of the cost is shared across the MISO North and Central regions, making regional grid projects – such as our Grid Forward: Central Wisconsin Project – an exceptional value for Wisconsin’s energy consumers.

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2022 Actuals

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2025 Projections

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2035 Projections

  • Natural Gas
  • Coal
  • Renewables (Solar/Wind/Other)
  • Carbon Neutral (Nuclear)

*Source: MISO Midwest Transmission Expansion Plan 2021 Future 2

The need for electric reliability

Every minute of every day, ATC is working behind the scenes to make sure the lights are on and the power is flowing. Safe and reliable electric power is our priority and our obligation. We maintain impeccable reliability standards for the system we operate.

As our energy landscape changes, we must evolve with it. Renewable generation – located in dispersed areas and dependent on weather conditions – requires a more robust electric grid to ensure energy consumer receive the energy they need in a timely, reliable and cost-effective manner.

The Grid Forward – Central Wisconsin Project will help relieve constraints on the electric grid, improve reliability, and provide access to lower-cost energy, including renewable generation.

Why is this project needed?

The regional grid is undergoing significant changes as generation moves legacy fossil fuel plants to intermittent renewable resources. This transformation requires a more robust electric grid - including new high-voltage power lines - to ensure power continues to be delivered safely and reliably.

What will this project cost?

The estimated cost of the Grid Forward - Central Wisconsin Project is approximately 1 billion (cost estimate by MISO in 2022 dollars), which will be cost-shared across the entire MISO North and Central regional footprint. The proposed new power lines will make extensive use of existing corridors to reduce the impact on local areas and communities, lowering construction costs and allowing for shorter in-service time.

What are the project benefits?

In the short-term, this project will provide economic benefits and support Wisconsin jobs during its construction. In the long-term, it will help relieve constraints on the electric grid, improve reliability, and provide access to lower-cost energy, including renewable generation. The overall cost of the project will be shared among several states, with Wisconsin rate payers historically shouldering just 13 to 16 percent of the total.

Grid Forward – Central Wisconsin Project

Three MISO-approved MVP projects are currently being proposed and developed within Wisconsin, and three separate utilities are cooperatively working on plans to develop these new high-voltage power lines within their existing service areas. These utilities include ATC, Xcel Energy and Dairyland Power Cooperative. Locations for the other two projects within Wisconsin will be sited and developed in western Wisconsin outside of ATC’s service area.

The Grid Forward – Central Wisconsin Project is the first of ATC’s Grid Forward portfolio of projects and includes:

  • A rebuild of approximately 160 miles of existing electric power lines to add a new approximately 200 mile 345-kV high-voltage line from the ATC Columbia Substation in Columbia County north to the ATC Arpin Substation in Wood County and west to the Xcel Energy Tremval Substation in Trempealeau County.
  • Expansion of the existing Arpin Substation.

*The proposed route from the Arpin Substation to the Tremval Substation is being co-developed by ATC and Xcel Energy

While approval for these projects came from MISO, each project will require regulatory approval from the Public Service Commission of Wisconsin and coordination with other select state agencies. Specific to ATC’s Grid Forward – Central Wisconsin Project, we intend to file an application with the PSCW in the summer of 2024. The project will require a Certificate of Public Convenience and Necessity. If approved, we expect to receive an order toward the end of 2025.

As part of the routing and siting process, the proposed new power lines will make extensive use of existing infrastructure corridors to help reduce the impact on local areas and communities. This will allow for shorter implementation time.

ATC conducts a thorough analysis to identify viable power line routes that balance landowner and environmental impacts. While we have rigorous process, we value input from those who know the land and communities best. The proposed routes ATC plans to submit generally follow existing utility and transportation corridors. Please click here to provide your comments, which will assist in our routing and siting process for this vital electric grid project.

Project Overview Map
Interactive Map
Project Documents