Ozaukee County Distribution Interconnection Project

PROJECT STATUS: Filed a revised application with the Public Service Commission of Wisconsin in September 2026.

Project Overview

ATC is proposing the Ozaukee County Distribution Interconnection Project, which includes new and rebuilt 345-kilovolt power lines, upgrades to existing electric facilities and construction of up to five new substations. Depending on the route selected by the Public Service Commission of Wisconsin, the project may also include two new 138-kV power lines.

The project extends across portions of Calumet, Fond du Lac, Manitowoc, Ozaukee, Sheboygan and Washington counties. ATC is proposing one preferred route and one alternate route, each consisting of northern and southern portions. Some portions of the project are common to both routes. If the project is approved, the PSCW will select one route for construction.

Project Need 

The proposed project will support growing electric demand in the region, including the Port Washington data center project, while helping to maintain a safe and reliable electric transmission system.

The project is subject to approval by the PSCW. Additional information about the proposed project can be found on the PSCW website under docket number 137-CE-229.

Project Description

Northern portion  

  • Build a new 345-kV power line connection between the Forest Junction Substation in Calumet County and the proposed Sheboygan River Substation in Fond du Lac County.
  • The preferred North West Route would primarily rebuild an existing power line within an existing corridor, while the alternate North East Route would use a combination of existing corridors, road corridors and new right-of-way.
  • Upgrade sections of existing power lines and complete related modifications to existing electric facilities.

Southern portion  

  • Build two new dual-circuit 345-kV power lines connecting the proposed Decker Substation in Port Washington to the existing electric system.
  • Rebuild and upgrade existing power lines between the proposed Mullet River Junction Substation in Sheboygan County and the proposed Cedar Creek Junction Substation in Washington County.
  • The preferred South East Route would primarily use existing power line corridors and if selected, build two new 138-kV power lines between the proposed Adell Substation and the existing Holland Substation in Sheboygan County.
  • The alternate South West route would also primarily use existing power line corridors and if selected, build a new dual circuit 345-kV power line extending from the town of Saukville, through the Fredonia area, and toward existing transmission lines near Farmington.

Substation work

  • Build the proposed Decker, Sheboygan River, Mullet River Junction and Cedar Creek Junction substations.
  • If the preferred South East Route is selected, an additional proposed Adell Substation would be built.
  • Complete upgrades at existing substations and install equipment needed to connect the new facilities and support reliable operation of the electric system.

Revised Application

ATC revised portions of the proposed routes based on additional field work, updated information and feedback received during review of the original application.

The PSCW will independently review the proposed routes and determine which routes, if any, may be approved.

Ozaukee County DIC Project

Milestones

September 2026

The revised application was submitted to the PSCW.

TBD

This will be updated when more information is known.

31 days after the PSCW's written order

Project construction is anticipated to begin 31 days after the PSCW’s written order.

17 months after construction begins

Approximately 17 months after construction begins, the project is anticipated to be in service.

September 2026

The revised application was submitted to the PSCW.

*Dates are anticipated and subject to changes
TBD

This will be updated when more information is known.

*Dates are anticipated and subject to changes
31 days after the PSCW's written order

Project construction is anticipated to begin 31 days after the PSCW’s written order.

*Dates are anticipated and subject to changes
17 months after construction begins

Approximately 17 months after construction begins, the project is anticipated to be in service.

*Dates are anticipated and subject to changes

Project FAQ's

A:

ATC develops proposed routes by considering a range of factors, including the use of existing utility and transportation corridors, engineering requirements, environmental resources, land use, safe construction and electric reliability. ATC compares potential route options and, per state law, proposes two routes that can be built, meet the identified electric need and satisfy applicable permitting requirements. The Public Service Commission of Wisconsin independently reviews the proposed routes and determines which route, if any, may be constructed.

A:

“Greenfield” generally refers to a portion of a proposed route that would require establishing new right-of-way for a power line rather than constructing or rebuilding the line entirely within an existing utility corridor.

A:

ATC seeks to use existing utility and transportation corridors when practical. However, existing corridors do not always connect the locations the project needs to serve. In those situations, new right-of-way is necessary. Where existing corridors are available, ATC also considers engineering requirements, environmental resources, land use, whether a route can be safely built, electric reliability and other factors when developing route options. These considerations help determine whether an existing corridor can be used and whether additional right-of-way is needed to develop route options that can be built and meet permitting requirements.

A:

Yes. The revised application removes the previously proposed east-west route through portions of the towns of Trenton and Saukville. ATC made this and other changes based on feedback received during the earlier regulatory review, additional environmental information and further project analysis.

However, the previously named Contingent Route remains in the revised application as part of the alternate South West Route.

A:

No. A proposed power line may follow or be located next to an existing power line corridor and still require new structures and additional right-of-way. The facilities needed, engineering requirements, and the amount of available space within the existing corridor help determine whether additional right-of-way is required.

A:

No. The existing power lines in that corridor must remain in service, and that route concept would still require two additional 345-kV power lines. Because the existing corridor is not wide enough to accommodate the additional lines, they would need to be built on new structures and require new easements adjacent to the existing corridor. This would be new construction, not a rebuild of the existing lines.

The route concept also would be longer than the two proposed greenfield route segments, require new easements through a federally protected natural area and require significant rerouting around Saukville because of nearby homes. ATC also considers how concentrating multiple power lines within the same corridor could affect electric reliability, safe maintenance and long-term operation of the electric system.

A:

The project is needed to reliably serve a load interconnection request by We Energies for a new large load addition in the Port Washington area and maintain the safe and reliable operation of ATC’s system.

A:

Yes. ATC revised portions of the proposed routes based on additional field work, updated information and feedback received during review of the original application.

A:

The Public Service Commission of Wisconsin has authority to approve, modify or deny the project. The Wisconsin Department of Natural Resources and other agencies also review applicable environmental permits and authorizations.

A:

The PSCW will establish opportunities for public participation as part of its review.

A:

If you have additional questions about the project or would like to discuss it in more detail, please contact Zac Tretow with ATC Local Relations at (262) 506-6901 or ztretow@atcllc.com.