As data centers surge, competition grows over who builds Wisconsin’s grid

The Midcontinent Independent System Operator (MISO), the regional grid operator for much of the Upper Midwest, recently reversed an earlier decision regarding a critical transmission project in eastern Wisconsin. The project, which includes a series of substations, was initially awarded to Viridon, a developer backed by investment firm Blackstone. However, MISO has now reassigned the project to the American Transmission Company (ATC), the dominant transmission owner in eastern and central Wisconsin. This reversal stems from the urgent need to supply power to a new $15 billion data center campus approved by Port Washington's city council, scheduled to come online by early 2028. ATC argued it was better positioned to complete the necessary infrastructure ahead of this demanding deadline, which is five years earlier than the project's original completion target. Viridon, despite submitting a plan to meet the expedited timeline, faced MISO's "uncertainty" regarding its ability to clear administrative hurdles in time, especially since it is not yet certified as a public utility in Wisconsin. The reassignment is a significant win for ATC and marks a first for MISO in reversing a project award due to timeline concerns. While a small portion of the substation costs will still be regionally shared, ATC now plans to fold the substations into a larger $1.3 billion grid buildout for the Port Washington campus, meaning Wisconsin ratepayers alone are expected to cover the majority of the remaining costs. Ratepayer advocacy groups, such as Wisconsin's Citizens Utility Board, have expressed concerns over the potential for increased consumer costs due to the project and ongoing debates over competitive bidding versus local monopolies in transmission development. The final outcome for these transmission projects, including their costs and exact siting, remains pending approval from Wisconsin's Public Service Commission.