Sierra Club, the Wisconsin Department of Natural Resources and Vantage Data Centers Management Company filed a joint stipulation in Ozaukee County Circuit Court on Oct. 16, 2026, asking the court to dismiss with prejudice Sierra Club's challenge to the air permits the DNR issued for Vantage's Port Washington Lighthouse Data Center Campus Project. Under the stipulation, the DNR will complete a statewide strategic analysis of artificial intelligence data centers by Jan. 31, 2028. Vantage will pay the full cost, and the DNR will keep sole control of the work.

The parties also agree that the Lighthouse construction and operation permits "remain valid, effective, and enforceable as of the date of this stipulation and order." The settlement arrives as Wisconsin's utility regulator says it has no direct regulatory oversight of data center development.

What the lawsuit challenged

On June 12, 2026, the DNR decided to issue Final Air Pollution Control Construction Permit No. 25-MIN-094 and Operation Permit 24618528A-F01 to Vantage for the Lighthouse campus. On July 10, Midwest Environmental Advocates, representing Sierra Club, petitioned the court for judicial review of that decision. The same day, Sierra Club asked the DNR for a contested case hearing on the permits.

On July 30, the DNR granted the contested case on one issue: whether the agency violated Wis. Stat. § 1.11 and Wis. Adm. Code ch. NR 150 by issuing the permits without preparing an environmental impact statement. The court granted Vantage's motion to intervene on Oct. 14, and the three parties filed the stipulation two days later. Assistant attorneys general signed it for the DNR on behalf of Attorney General Joshua L. Kaul.

Sierra Club's contention that an EIS was required is not resolved by the settlement. The stipulation states that nothing in it "constitutes a determination that additional environmental review is required for the issuance of those permits and approvals."

The project at issue

Wisconsin Public Radio describes Lighthouse as a $15 billion campus of four data centers on roughly 670 acres, developed by Vantage with Oracle and OpenAI to expand AI capacity. WPR reports that the first phase would use 1.3 gigawatts and that the project could eventually require up to 3.5 gigawatts. According to WPR, the campus could create more than 4,000 construction jobs and more than 1,000 permanent positions, with construction expected to finish in 2028.

What the DNR must study

The stipulation requires the DNR to prepare a "Data Center Strategic Analysis" under Wis. Adm. Code § NR 150.10(1m)(c). It defines a strategic analysis as an environmental and alternatives analysis of an issue or policy, conducted under the procedures in NR 150.10. At a minimum, the DNR must hold a public comment period during scoping, one or more public hearings on the analysis, and maintain a public website with notices, documents and opportunities for participation.

The analysis must, at a minimum, address:

  • a base case covering the anticipated build-out of AI data centers and associated energy infrastructure under current plans and projections
  • existing state, local and federal authorities
  • alternative courses of action, to be determined through public scoping
  • direct, indirect and cumulative effects of the base case and alternatives, including mitigation, on aesthetics and light, agriculture, air quality, climate, cultural resources, the economy, energy use, greenhouse gas emissions, land use, noise, temperature, water quality, water use, waterways, wetlands and wildlife
  • summaries of other areas of public concern, including energy bills

Who pays, and who controls it

Vantage must cover the full cost of preparing the analysis, including DNR and other state agency staff time, consultants, printing and postage. The DNR will invoice Vantage quarterly, and Vantage must pay each invoice within 30 days. The DNR keeps sole responsibility for the process, including scoping and hiring staff and consultants. Vantage may not prepare any part of the analysis, though it may provide relevant information and participate as other members of the public can. The DNR also retains full authority to determine compliance with § 1.11 and NR 150 for any future application or project.

In a statement reported by WPR, the DNR said that under the settlement it "will be able to conduct the independent strategic analysis at no additional cost to Wisconsin taxpayers." MEA attorney Michael Greif said the statewide review would offer "a holistic, comprehensive look at the environmental impacts and the financial impacts" of AI data centers, WPR reported. Mark Freeman, Vantage's vice president of global marketing, said, "The analysis will examine the environmental and economic considerations associated with data center development."

WPR also reports that the deal "does not pause permitting of data center projects while the state completes its review."

The state's energy planning backdrop

The Public Service Commission of Wisconsin sought public comment in August and September on its draft 2026–2032 Strategic Energy Assessment, which draws on historical data and forecasts that ten electric providers submitted in November 2025. The PSC held a virtual public hearing on Aug. 20, 2026, and its written comment period closed on Sept. 28, 2026. In announcing the comment period, the commission said Wisconsin has no integrated resource planning process and that the PSC "has no direct regulatory oversight of the development or operations of data centers." The draft assessment found "electricity demand could grow more than 40 percent by 2032 due to demand from hyperscale data centers," according to WPR. The PSC has said it requested updated forecasts from electric providers for the final assessment.

What Happens Next

  • Court order: The stipulation asks the court to enter an Order for Dismissal of Case 2026CV000294 with prejudice and without costs. The parties waived their right to appeal that order.
  • Contested case withdrawal: Sierra Club must withdraw its July 10 petition for a contested case hearing at the DNR no later than five days after the dismissal order is entered.
  • Records: The DNR must provide records responsive to Sierra Club's public records request 26PRR12987 by Nov. 30, 2026.
  • Strategic analysis: The analysis is due by Jan. 31, 2028. Dates for its comment period, hearings and website launch have not been set.

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