Aterio, who are a provider of forward-looking data on U.S. infrastructure development, did a publication on an analysis of Project Lighthouse that is located at the Port Washington. The Wisconsin campus is being constructed by Vantage Data Centers for Oracle. According to regulatory filings that were reviewed through September 24, 2026, Aterio sees a material risk the site misses Oracle’s second-half 2027 delivery guidance. Also, it sees meaningful load unlikely to be met before mid-2028. However, Vantage has said it expects full campus buildout by 2028.
What is the Limiting Factor
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. Also, the construction works on the high-voltage interconnection can’t commence without approval from the Public Service Commission of Wisconsin (PSC). With grid power emerging as a major factor limiting data center development in the US, also availability of adequate water for running the data centers is a key challenge.
ATC Seeks New Approval for the High-Voltage Interconnection Project
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 for another approval in September. This therefore resets the statutory clock under a new docket.
“Construction at Port Washington is progressing steadily. However power delivery relies on a regulatory process that has restarted,” stated 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.”
Expected Timelines Regarding Project Lighthouse
Aterio has modelled three timelines based on when the PSC issues its written order:
Earliest legal path: partial power around October 2027. As for the full 1.3 GW capacity, it is exotic around August 2028. Unlikely, since no comparable Wisconsin case has moved this fast.
Base case (180-day decision): partial power around December 2027. The full capacity is projected 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.
PSC to Decide on the Interconnection Project in October 2026
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 issue the way forward.
Project Lighthouse Factsheet
Project Name: Project Lighthouse
Location: Port Washington, Ozaukee County, Wisconsin, USA
Developer / Owner: Vantage Data Centers
Primary Tenant / End User: Oracle Corporation
Total Planned Capacity: Up to 1.3 GW total load capacity
Physical Footprint: 672 acres; 4 single-story data center halls (2.5 million sq. ft.)
Construction and Operational Progress
Construction Start: December 2025
Current Status: On schedule; permits secured, continuous construction; 2 of 4 halls fully enclosed.
Limiting Bottleneck: High-voltage grid interconnect approvals (not physical construction).
Regulatory and Grid Interconnect Status
Transmission Operator: American Transmission Company (ATC)
Regulatory Body: Public Service Commission of Wisconsin (PSC)
Regulatory Timeline Reset: ATC’s original application was rescinded by PSC in August 2026 due to extensive scope changes. Refiled in September 2026, resetting the regulatory review clock.
Next Key Milestone: PSC completeness determination (expected October 19, 2026) & MISO voltage-stabilization device filing.
Aterio Timeline Projections (as of Sept 2026)
Oracle Guidance (Original): Second-half 2027 delivery.
Base Case (180-Day Regulatory Review): Partial power by Dec 2027; full capacity by Oct 2028; load ramps Q1 2028.
Extended Review Case (360-Day Review): Partial power by June 2028; full 1.3 GW capacity by April 2029.
Developer Target: Vantage Data Centers targets full campus buildout by 2028.
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