Restarted transmission review puts meaningful power at Vantage’s Port Washington campus closer to mid-2028 than Oracle’s 2027 target

Aterio, a provider of forward-looking data on U.S. infrastructure development, today published an analysis of Project Lighthouse, the Port Washington, Wisconsin campus Vantage Data Centers is building for Oracle (NYSE:ORCL). Based on regulatory filings reviewed through September 24, 2026, Aterio sees a material risk the site misses Oracle’s second-half 2027 delivery guidance, with meaningful load unlikely before mid-2028. Vantage has said it expects full campus buildout by 2028. The full report is available on the Aterio website.

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Left: campus electrical plan (sheet SO-E01-00). Green blocks are data modules, blue blocks are spines and red blocks are the 13 planned central utility plants. Right: Vantor satellite imagery, 10 September 2026.

Construction does not appear to be the limiting factor. Permits are in hand, work has run continuously since December 2025, and satellite imagery shows two of the four halls enclosed. The constraint is grid power. The campus can’t operate until American Transmission Company (ATC) builds a new high-voltage interconnection, and that work can’t begin without approval from the Public Service Commission of Wisconsin (PSC).

That approval process has started over. ATC’s first application spent ten months under review before the PSC revoked its completeness finding in August and closed the case, citing hundreds of post-filing changes to the project’s scope. The Commission was clear it wasn’t ruling on the merits. ATC refiled in September, resetting the statutory clock under a new docket.

"Construction at Port Washington is progressing steadily, but power delivery depends on a regulatory process that has restarted," said Javier Reyes, Head of Data Center Research, Aterio. "Based on the public record, we see a meaningful risk that load arrives later than Oracle’s current guidance."

Aterio models three timelines based on when the PSC issues its written order:

Earliest legal path: partial power around October 2027 and the full 1.3 GW around August 2028. Unlikely, since no comparable Wisconsin case has moved this fast.
Base case (180-day decision): partial power around December 2027 and full capacity around October 2028. After commissioning, customer load ramps mainly from Q1 2028.
Extended review (360 days): partial power around June 2028 and full capacity around April 2029. The PSC used its extension in every comparable large transmission case Aterio reviewed.

The analysis comes as Oracle expands its AI infrastructure footprint. On September 24, Oracle sent a force majeure notice on Project Jupiter, its Stargate campus in New Mexico, citing a delayed gas pipeline and a pending air permit. Oracle has said Project Jupiter remains on schedule, and the notice has no direct bearing on Port Washington. At roughly 900 MW of IT load, Lighthouse is comparable in scale to the new capacity Oracle delivered in its most recent quarter.

The next milestone is the PSC’s completeness decision, expected around October 19, 2026, alongside ATC’s filing with grid operator MISO on a voltage-stabilizing device near the campus substation. Aterio will update its assessment as regulators act. Read the full analysis, including building-level load estimates and expansion plans beyond the initial four halls.

Aterio is an independent data provider and does not hold or trade securities of Oracle or any other company named in this release. Dates in this release are Aterio estimates based on public regulatory filings, state law and past PSC cases, and are not commitments by ATC, the PSC, Vantage or Oracle. Actual timing could differ materially.

About Aterio

Aterio provides real-time, facility-level intelligence on U.S. data center development, power demand, and digital infrastructure growth. Its continuously updated dataset tracks active, under-construction, and announced projects for investors, energy companies, infrastructure providers, and strategic planners. Learn more at www.aterio.io.

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Aterio Data Team

data@aterio.io