Wisconsin
Data centers in Rock County
We track 2 projects inside Rock County and 1 more within 25 miles of it. For a distance-specific answer, check your own address.
In Rock County
Filed
MW not reported
A data center code named Project Cornmaze is proposed across more than 430 acres in the Towns of Beloit and Turtle, first pursued under a predevelopment agreement with Cambrin LLC before Panattoni Data Centers took over as developer in April 2026. Cambrin LLC's paperwork shares a name and contact address with filings tied to Meta's confirmed Beaver Dam project, but Meta has not confirmed any role here. After residents raised concerns about NDAs and a lack of transparency, the Town of Beloit board voted June 1, 2026 to require board approval before staff can sign any future nondisclosure agreement.
Withdrawn
800 MW
Janesville Hearing Nov 3, 2026
Viridian Acquisitions proposed an 8 billion dollar, 11 building, 800 megawatt data center campus on the city owned former GM/JATCO auto plant site, which closed in 2008. After a 4,000 signature petition and months of packed public meetings, the Janesville City Council voted unanimously in June 2026 to let its letter of intent with Viridian expire, ending the specific proposal. Voters will still decide a November 3, 2026 referendum requiring a citywide vote before any future project over 450 million dollars can be approved on the site's undeveloped portions.
Within 25 miles of Rock County
20 mi NEOperatingWalworth County, WI
Power bills in Rock County
Most of the county is served by Alliant Energy.
Meta says the contract means other Alliant customers will not pay for the energy used by its Beaver Dam data center, though consumer advocates say the secrecy around the deal makes that hard for the public to independently verify. Alliant Energy (Wisconsin Power and Light) general rate case for 2026 and 2027 (docket 6680-UR-125) raised residential rates 5.4%, decided November 6, 2025: about $7 to $10 a month on a $160 bill. Transmission upgrades like this are typically billed to every electric customer in the state through transmission charges, not just to the data center that made the new line necessary, which is why the cost allocation question matters for ordinary bills even outside the four counties involved.
Alliant Energy's Wisconsin utility asked for an electric increase of about 8.3 percent in 2026 and 5.7 percent in 2027, plus a smaller natural gas increase, citing grid investment. The Public Service Commission approved a unanimous settlement, trimming the increase to 5.4 percent in 2026 and 5 percent in 2027 on electric rates, which works out to about 9.57 dollars a month more on a typical residential bill in 2026 and 17.45 dollars a month more in 2027 compared with 2025.
Alerts for Rock County
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