Grid Forward – Central Wisconsin Project advances into construction, remains aligned with original cost estimate

PEWAUKEE, Wis. - ATC continues to make progress on the Grid Forward - Central Wisconsin Project, with construction underway, key milestones being achieved and the project remaining on schedule for its planned December 2030 in-service date.

ATC began transmission line construction in the second quarter of 2026 and recently installed the project's first transmission structure, marking an important step as the project moves from planning into active construction. The project is currently approximately 5% complete.

The Grid Forward - Central Wisconsin Project was approved as part of the Midcontinent Independent System Operator's Long Range Transmission Planning Tranche 1 portfolio and is designed to strengthen the regional electric transmission system, support long-term reliability and improve the ability of the grid to meet future energy needs across central Wisconsin and the broader Midwest.

"Grid Forward is an important investment in the region's electric infrastructure and future reliability," said Eric Lundberg, senior vice president of Asset Delivery. "Construction is underway, major milestones are being achieved and the project remains on track. As the project advances, it is important that stakeholders understand both the progress being made and the context behind project cost information they may see through MISO's reporting processes."

Recent project accomplishments include:

• Installing the first transmission structure as the project moves into active construction.
• Advancing detailed engineering and design activities across multiple transmission line segments and substations.
• Continuing permitting and material procurement activities to support future construction work.
• Maintaining the planned December 2030 in-service date.

"ATC supports transparency and accountability for major infrastructure projects," Lundberg said. "As projects move from planning to construction, it is important that cost information be evaluated on a comparable basis and with appropriate context. A simple comparison between an early planning-level cost estimate and a current construction forecast does not always tell the complete story."

ATC's analysis indicates the Grid Forward - Central Wisconsin Project is forecasted to remain within the cost range approved by the Public Service Commission of Wisconsin and within approximately 2.5% of MISO's original cost estimate when compared on a time value of money basis.

MISO's original cost estimate was developed during the planning process and expressed in 2022 dollars. The current project forecast reflects additional years of inflation, refined engineering, project development activities and approved project modifications that occurred as the project advanced through regulatory review and into construction. When those factors are evaluated on a comparable basis, ATC's analysis indicates the project remains closely aligned with MISO's original cost estimate.

The project also is expected to provide significant long-term benefits for Wisconsin customers. Revenue requirement analysis prepared in support of the project estimates approximately $1.75 billion in net savings for Wisconsin customers over the life of the project. On a discounted basis, those savings are estimated at approximately $142 million.

The Grid Forward - Central Wisconsin Project includes rebuilding existing infrastructure and constructing new 345-kilovolt transmission facilities needed to strengthen the regional transmission system, improve reliability and support Wisconsin's growing energy needs.

For more information about the Grid Forward - Central Wisconsin Project, visit ATC-gridforward.com.

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