American Transmission Company Port Washington data center interconnection project
Pending Statewide before the Public Service Commission of Wisconsin.
No residential dollar figure published yet
The filing does not state a typical-bill impact we can verify. We will add one when the commission staff or the consumer advocate publishes it.
American Transmission Company wants to build a high voltage transmission line and five new substations across Fond du Lac, Ozaukee, Sheboygan and Washington counties, at a cost of more than 1.3 billion dollars, largely to connect the Vantage data center campus in Port Washington to the grid. On August 7, 2026 the Public Service Commission voted to make ATC restart its application after finding the company had made too many design changes during the review, resetting the case's review clock. Microsoft and ratepayer advocates have separately objected to how the plan would allocate the line's cost.
What it means for your bill: Transmission upgrades like this are typically billed to every electric customer in the state through transmission charges, not just to the data center that made the new line necessary, which is why the cost allocation question matters for ordinary bills even outside the four counties involved.
- Status
- Pending
- Utility
- Statewide
- Commission
- Public Service Commission of Wisconsin
- Data center linked
- Yes. The filing ties part of the cost or the tariff design to data center load.
- Last checked
- August 29, 2026
How to comment
The Public Service Commission of Wisconsin accepts written comments on the docket while the case is open, and holds public hearings on major cases. Commission site. Citizens Utility Board of Wisconsin represents households in this case.
Sources
- Wisconsin regulators send ATC back to the drawing board on data center connection project, Wisconsin Watch, 2026-08-07
- State regulators deal blow to power line proposal for Port data center, Milwaukee Journal Sentinel, 2026-08-06
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