TL;DR · 30-second read

The Short Version

A huge data center campus is being built in Port Washington, Wisconsin. To plug it into the electric grid, it needs new high-voltage power lines and substations costing $1.3 billion to $1.7 billion.

Wisconsin’s utility regulators just sent that power-line plan back to square one. The company behind it changed its paperwork so often, filing or refiling 564 documents, that officials and the public could not keep up.

The takeaway: a building can go up faster than the wires that power it.

Wisconsin’s Public Service Commission (PSC) voted unanimously on Thursday to revoke its “completeness” determination for American Transmission Co.’s application to build the Ozaukee County Distribution project, Wisconsin Public Radio reported. The project is a package of new substations, new high-voltage transmission lines and upgrades to existing infrastructure. ATC told regulators it is needed to serve the hyperscale data center campus under construction in Port Washington. A revised application filed in July put the cost at $1.3 billion to $1.7 billion, and the work would have spanned six counties.

The vote closes the current case and eliminates the December 2026 deadline for regulators to rule. ATC must now file a new application in a new proceeding. The commission did not deny the project. But the reset undercuts ATC’s plan to begin construction in December and finish by the end of 2027.

Executive Summary

The PSC withdrew its finding that ATC’s application was complete enough to review. Commission chair Summer Strand said ATC filed or refiled 564 application documents after the December 2025 completeness determination. She called the result a “moving-target application” that left staff unable to prepare evidence and kept intervening parties and the public from participating meaningfully. ATC and a ratepayer watchdog both said they could not recall the commission taking this step in recent decades, if ever.

The decision matters beyond the six counties the line would cross. It separates two things developers often treat as one schedule: building a data center and energizing it. The Port Washington campus is under construction. The $1.3 billion to $1.7 billion of grid work that ATC says the campus needs is now back at the start of state review, with no ruling deadline in place.

Vantage Data Centers, one of the campus developers, said it respects the commission’s role but is disappointed. ATC said it is “considering its options.” Neither company has said when a new application will be filed or how the reset affects the campus’s power-on dates.

The Campus Is Rising; Its Power Line Just Went Back to Start

The Port Washington case shows a data center moving faster than the infrastructure it depends on. ATC stated in PSC filings that the Ozaukee County Distribution project is needed to provide electric service to a data center that is already under construction. Under ATC’s plan, regulators would rule by December 2026, construction would begin in December, and the buildout would be complete by the end of 2027. Thursday’s vote removed the first step of that sequence, and the others depend on it. A new application means a new proceeding, a fresh completeness review, and a new statutory clock that starts only once regulators again find the filing complete.

Chair Strand was direct about the cost of that reset: “I recognize the impacts this decision will have on construction timelines and in-service dates for the project.” In-service date is utility shorthand for the day a line is energized and able to carry power. For a hyperscale campus, the kind of facility being built to meet cloud and AI computing demand, that date matters more than any other. Until it arrives, a finished data hall cannot run the servers it was built for.

The mechanism is two approval tracks moving at different speeds. The building advances on local approvals and private capital. The wires require a state certificate, reviewed in a contested proceeding in which staff, intervenors and the public all have a role. The size of the dependency is set by the $1.3 billion to $1.7 billion estimate: substations, new high-voltage lines and upgrades across Ozaukee, Washington, Sheboygan, Calumet, Fond du Lac and Manitowoc counties. When the grid track slips, the delay falls on the developers, on ATC’s capital plan, and on whichever tenants eventually expect to occupy the campus.

What 564 Filings Did to a Legal Clock

In Wisconsin, a major transmission project needs a certificate of public convenience and necessity (CPCN), the state’s permission to build a large utility facility. A completeness determination is the gate into that process. It confirms the application contains what regulators need, and it starts the deadline for a decision. Commissioner Marcus Hawkins described the logic: “We have strict timelines that are feasible only when we have a complete application.” If the application keeps changing after that gate, the deadline stays fixed while the thing being reviewed does not.

That was the commission’s core finding. According to Strand, ATC filed or refiled 564 documents after being found complete in December 2025. The commission’s administrative law judge had raised concerns last month about missing and changing information. All three commissioners criticized the volume of changes. The reasoning is procedural, not a verdict on whether the line is needed. Staff cannot build an evidentiary record, and parties cannot respond, when the proposal keeps moving.

ATC’s counterargument deserves a fair hearing. Its attorneys wrote that “in its entire history, the Commission has never revoked a determination that a CPCN application is complete,” and argued against doing so here. Large grid projects serving new, very large loads can change as the load itself is refined, and a restart is a costly remedy. The commission weighed that against the integrity of the review and chose reviewability. Both positions protect something real. The open question is which of them ATC’s revisions were actually driven by.

A Precedent That Will Shape the Next Filing

A first-ever revocation signals a lot to every utility preparing a large application in Wisconsin. The practical lesson for transmission owners and data center developers is to settle project scope before filing, not during review, because a regulator has now shown it will reset the clock rather than review a shifting target. That raises the value of early coordination between the developer’s load plans and the utility’s design. It also raises the cost of filing early to secure a place in the schedule.

The decision also landed amid visible public opposition. Residents and anti-data center activists pushed back on the project, and comedian Charlie Berens submitted comments to the PSC arguing it was “no longer clear to the public or public officials what their actual plans are.” Opponents framed the issue as transparency. The commissioners framed it as process integrity, grounding their vote in the volume of changes rather than in objections to the data center. The outcome addresses the transparency concern procedurally, by requiring a stable application the public can review. It says nothing yet about whether the project should ultimately be built.

For Vantage, the statement that it will pursue “responsible development” of the needed transmission suggests it expects to see the project through. How quickly that can happen now depends on how fast ATC can refile a fixed application and how long a restarted proceeding takes.

Background

American Transmission Co. is a transmission-only utility that builds and operates high-voltage power lines across much of Wisconsin. Major new lines require a certificate from the Public Service Commission of Wisconsin, the three-member state body that regulates utilities. The commission reviews applications in formal proceedings in which staff, intervening parties and the public can weigh in, under deadlines that begin once an application is found complete.

Port Washington, in Ozaukee County north of Milwaukee, is the site of a hyperscale data center campus. Vantage Data Centers is one of its developers. Campuses of this scale need far more electricity than local distribution networks were built to deliver. That is why ATC proposed the Ozaukee County Distribution project, which the PSC found complete in December 2025 before the application’s many subsequent revisions led to Thursday’s revocation.

Sources

Source: PSC deals major blow to transmission project supporting Port Washington data center (Wisconsin Public Radio). Report on the Wisconsin PSC’s vote to revoke the completeness determination for ATC’s $1.3 billion to $1.7 billion Ozaukee County Distribution project.