Dunn County explores zoning options for small modular data centers after utility outlines grid limits

The Dunn County Planning, Resources and Development Committee on July 2 asked staff to draft zoning and policy options aimed at small modular data centers after a presentation from Dunn Energy Cooperative on local transmission and substation limits.

Jesse Singer House, general manager for Dunn Energy Cooperative, told the committee that while the cooperative's system can accommodate some additional load on paper, most rural substations can add only about 27 megawatts without costly transmission upgrades. "We're agnostic on what that load is, behind the meter," he said, explaining that utilities evaluate new customers by their physical footprint, interconnection cost and impact to member rates.

The presentation framed how capacity (the maximum instantaneous electric draw) and energy (total production over time) differ and why both matter to siting and permitting decisions. Singer House said new large loads typically pay the full cost of interconnection and upgrades and receive specialized rate structures to avoid passing costs to other members, but he cautioned that additions across the MISO regional footprint can affect wholesale prices and lead to higher rates for members.

Committee members then reviewed details of a NODIAC proposal relayed to the committee. According to the company summary provided to staff, the project under consideration is a 2-megawatt modular data center sited on roughly one-quarter to one-half acre with two containerized units about 10'12 feet tall. The company said it would use closed-loop cooling, truck in makeup water (initial fill about 3,000'1,000 gallons of a propylene-glycol/water mix that is replaced only every 5'8 years), rely on air-cooled chillers, and conduct a noise study before construction; company representatives told staff they expect minimal ordinary traffic and no regular on-site workforce.

Tammy (county staff) and committee members pressed for operational details and environmental safeguards. Questions focused on water handling and disposal, potential electronic interference, noise at the property boundary (the company estimated roughly 70 decibels at the fence), and how long-term leases or tax assessments would work. Committee members were also concerned with the zoning tools available: several supervisors said they preferred regulating by land-use characteristics (acreage, setbacks, noise limits and review timelines) rather than by a strict megawatt threshold, which could inadvertently restrict other legitimate rural uses.

"Today, we're not making any final decisions," the chair said, emphasizing that the session was to frame a predictable, timely review process rather than to approve a specific project. The committee directed Tammy to prepare multiple draft options for future meetings: one that defines and regulates data centers specifically, and a second, broader option that would create a framework for "emerging technologies" with clear review standards.

Jesse Singer House was invited to return for follow-up meetings to provide technical input; staff said they would consult with county counsel and the cooperative as they craft options. The committee did not approve or deny the NODIAC proposal at the July 2 meeting.

What happens next: staff will return with multiple draft regulatory options for committee consideration; the cooperative and the company were scheduled to appear at additional upcoming meetings.