ATC refiles Wisconsin transmission application, putting Oracle campus power timing at risk

American Transmission Company (ATC) refiled its application on September 18, 2026, restarting Wisconsin’s review of the high-voltage connection for Project Lighthouse, the four-building data-center campus Vantage is developing in Port Washington for Oracle. The restart puts power-delivery timing at risk; one extended-review scenario estimates full 1.3 GW availability around April 2029.

Why the review restarted

The Public Service Commission of Wisconsin (PSC) closed ATC’s first case on September 10, 2026, without ruling on its merits. ATC filed again eight days later, restarting the statutory review process.

The review began after ATC applied for approval of the transmission project in September 2025. The PSC found the application complete in December 2025 and began its formal review. From January through July 2026, ATC filed 564 additional documents and made project changes that included route revisions, temporary bypass lines and updated cost estimates. An administrative law judge ordered ATC to itemize the alterations on July 1 and found on July 15 that ATC had not complied. The PSC withdrew its completeness finding in August.

The campus needs a transmission connection

Vantage is developing Project Lighthouse for Oracle as four planned data-center buildings in Port Washington. ATC’s application sought approval for a new high-voltage line to serve the campus.

Grid power alone does not make the buildings ready to carry customer workloads. Their electrical and cooling systems still need to be energized, tested and commissioned. The first transmission stage would provide partial service, followed by those steps at the buildings.

Oracle’s separate Point Beach electricity proposal for the same campus was covered in NeoTeo’s earlier article.

What 902 MW and 1.3 GW measure

Project Lighthouse is described as having 902 megawatts (MW) of critical IT load—the power for its computing equipment—and total electrical demand of 1.3 gigawatts (GW). The larger figure includes cooling and other site consumption, so the two numbers describe different parts of the campus’s power needs.

Two conditional power-delivery scenarios

The estimates depend on how long the PSC’s review takes. A base-case scenario assumes a decision within the initial 180-day review period; an extended-review scenario assumes the PSC uses a 180-day extension.