The utility that builds many of Wisconsin’s power lines wants to add more than $2 billion in new transmission infrastructure to serve Wisconsin’s data centers, alarming data center critics.
American Transmission Company LLC has requested or received approval from the Public Service Commission to build between $2.63 billion and $2.98 billion in new transmission lines and substations, according to WisBusiness.
That includes two pending projects before the PSC that would serve Microsoft and Vantage’s data centers in southeastern Wisconsin. Also included in that total are three already-approved projects serving Microsoft’s Mount Pleasant campus and Meta’s Beaver Dam data center set to cost at least $1.18 billion.
Intervenors in two tariff cases before the PSC have raised concern about who will pay for that new transmission infrastructure, pointing out that ATC’s typical cost-sharing structure would require other ratepayers to cover the cost of much of the initial construction of these facilities.
“The tariff has to be passed under a no-harm standard, and our view is saddling customers with transmission costs does harm them,” said Tom Content, executive director of the Citizens Utility Board.
We Energies, which will power the Microsoft and Vantage facilities, says its data center customers will pay $564 million over the next two years to fully cover their related transmission costs. But the utility has offered limited detail; Microsoft and Vantage have also declined to offer additional comment.
“What our customers should know is that all parties agree that customer rates will not be impacted by data centers,” Brendan Conway, director of media relations for We Energies and WPS parent WEC Energy Group, wrote in a Thursday email. “That is the commitment the data centers have made.”
Both We Energies and Alliant, which serves the Beaver Dam data center, maintain that other ratepayers will not be impacted by the addition of new data centers.
In August and September of last year, ATC submitted applications to the PSC for two new transmission projects. One of those proposals, which would install between 90 and 102 miles of new extra-high voltage cable in and around Ozaukee County, is set to cost between $1.36 billion and $1.64 billion alone.
The transmission utility already had three other transmission projects pending before state regulators from the prior year;: these were approved between May and November of 2025.
Between all five projects, ATC is planning to install hundreds of miles of high-voltage transmission and build up to nine new substations across 11 counties. Read more.
