ATC files revised application for the Ozaukee County Distribution Interconnection Project

Application includes changes informed by recent Commission Order, stakeholder feedback and additional environmental review

PEWAUKEE, Wis. - ATC has filed a revised application with the Public Service Commission of Wisconsin for approval of the Ozaukee County Distribution Interconnection Project.

The proposed project is needed to support increased electric load in the Port Washington area and maintain the safe and reliable operation of the regional electric transmission system. The project includes facilities in portions of Calumet, Fond du Lac, Manitowoc, Sheboygan, Ozaukee and Washington counties.

The customer at the Lighthouse campus is committed to paying its own way when it comes to the energy needed to power its facilities. The customer is also, through its rates, committed to fully funding the cost of transmission infrastructure built to provide it with service.

ATC originally submitted an application for the project in September 2025. Following the PSCW's decision to revoke the completeness determination for that application, ATC prepared and submitted this revised application.

The revised application includes several changes informed by the Commission and its staff, stakeholder feedback, additional environmental information and project analysis completed since the previous filing. The updates include a new preferred route in the southern portion of the project, the removal of a previously proposed east-west route and other route and facility refinements.

Key changes include:

• Designation of the South East route as the preferred route in the southern portion of the project and the South West route as the alternate route.
• Removal of the previously proposed east-west route through portions of the towns of Trenton and Saukville.
• Removal of certain previously proposed facilities east of the Mullet River Junction Substation that are no longer needed.
• Addition of an E-STATCOM adjacent to the proposed Decker Substation to help maintain reliable electric system operation.
• Simplified route names that use directional descriptions and are identified by color on the project maps: North West (Green), North East (Red), South West (Red) and South East (Green).
• ATC preference for the two green route segments.
• Incorporation of the former Contingent route into the South West route option.
• Additional temporary bypass segments to support safe and efficient construction while maintaining reliable transmission system operation.

A map of the new proposed routes can be found here.

The proposed routes make substantial use of existing power line corridors. ATC seeks to use existing corridors where practicable, but new corridors are necessary when existing corridors cannot reasonably accommodate the facilities needed for the project. ATC's routing and siting process considers factors including landowner impacts, environmental considerations, engineering and constructability, cost and the use of existing corridors.

"The need for this project has not changed, but the application has," said Jared Winters,

executive vice president and chief assets officer for ATC. "Since the previous filing, we've substantially improved our application by continued gathering of information from landowners, local officials, state agencies and other stakeholders while conducting additional environmental review and project analysis. That work informed changes to the proposed routes and project design.

"The revised route configuration reflects additional feedback, analysis and routing and siting work, and we believe it represents the most responsible, buildable and electrically sound option for serving this significant new electric demand. We appreciate the input we've received and will continue that engagement as the PSCW review process moves forward."

The project would include new and rebuilt power lines, modifications to existing infrastructure and construction of up to five new substations. If the project is approved, the PSCW will select one northern route and one southern route as part of its review process.

After the PSCW determines the application is complete, the Commission will announce opportunities for public comment as part of its review. ATC and its project partners support continued public participation throughout the regulatory process. The project also requires review by the Wisconsin Department of Natural Resources.

Additional project information, including updated maps, fact sheets, frequently asked questions and a project overview video, is available at atcllc.com/projects. Select Ozaukee County Distribution Interconnection Project from the drop-down menu.

ATC is a Wisconsin-based company that moves energy along the regional electric grid in parts of Wisconsin, Michigan, Minnesota and Illinois, serving more than 5 million electric consumers. We are experts at what we do: planning, maintaining, operating and protecting the grid. As the electric industry moves toward renewable generation sources, we are transforming our system to continue delivering energy reliably and safely. We proudly support STEM education programs that empower youth with the skills needed to succeed in tomorrow's energy workforce. For more information, visit www.atcllc.com