Grant County subcommittee advances data center ordinance draft, debates crypto inclusion, power and noise limits

Grant County’s Data Center Subcommittee met May 27 to continue a line‑by‑line review of a proposed data‑center ordinance, advancing several draft choices while leaving final decisions to the Area Plan Commission (APC) and county commissioners.

The advisory subcommittee discussed whether cryptocurrency mining should be regulated in the same ordinance as data centers or in a separate rule. Some members argued mining uses the same equipment and heavy electricity and should be included; others said the fast‑moving technology argues for a separate, quickly amendable ordinance. The group agreed to leave language in the draft for now and revisit the issue later when more information is available.

Members discussed limits on site size and setbacks. The draft retained a 10‑acre minimum and 100‑acre maximum for parcel size; the committee clarified that required setbacks are to be measured from property line to property line. Committee members debated a 1/4‑mile setback (discussed in feet as 1,320 and 1,420 during the meeting) and deferred final numeric math to staff and future meetings.

A major policy preference in the draft is limiting a data center’s reliance on the local electrical grid. The subcommittee considered language directing that site connections be limited to routine office power and fire suppression and that primary data‑center operations be self‑sustaining with on‑site generation. Members acknowledged state and federal constraints could force changes later but favored the stronger language as protective for the county unless prohibited by higher authority.

On cooling and water use, the committee expressed a strong preference for closed‑loop cooling systems and for requiring applicants to submit detailed cooling and water plans. Several residents and committee members warned that mandating closed‑loop systems might exclude future, lower‑impact technologies; the subcommittee agreed applicants could seek variances or propose amendments as new technologies emerge, but the draft will prioritize closed‑loop systems.

Noise and vibration drew substantial discussion. Members emphasized that any numeric decibel limit must specify measurement methodology and units (for example, A‑weighting and LEQ averaging used by ANSI/ANSI‑equivalent standards) and align with county noise measurement practice. Committee members tested ambient sound informally and proposed a working placeholder of 40 dB for continuous noise at nearest residential boundaries, while noting further study is needed to set a defensible standard. The draft also contemplates requiring developers to pay for an acoustic study prepared by a qualified professional.

The subcommittee considered generator testing, whether it should be limited to weekdays, and whether testing should be treated as continuous operational noise. Members suggested defining generator testing and folding it into continuous operation limits to avoid separate exemptions for weekday testing.

On vibration, the committee discussed lower thresholds near historic structures and the need for applicants to submit engineering analyses. For equipment setbacks and sound mitigation, members proposed moving an equipment setback item into the noise section and tentatively set an equipment setback of 250 feet from property lines with required berms, screening or sound enclosures.

Public commenters raised several concerns. Resident June Brown asked who would enforce water testing and what happens if a developer goes bankrupt; she warned about possible health and environmental impacts from on‑site generation and infrasound (low‑frequency vibration) and urged the committee to allow alternative cooling methods if they prove environmentally superior. Committee members said enforcement and remediation would rely on permitting, bonding and financial assurances reviewed by the BZA and drainage board.

Financial assurance and transfer of ownership were discussed at length. Some members opposed accepting letters of credit as insufficient security and favored insurance or A‑rated bonds and clear county approval of any transfer of ownership, including the ability for the county to reject ownership changes if public interest requires it. The committee asked staff to draft language excluding letters of credit or otherwise tightening acceptable forms of assurance.

On stormwater and hazardous materials, the subcommittee asked that drainage‑board review be explicitly required for stormwater management plans and confirmed the county’s standard 75‑foot regulated‑ditch setbacks remain applicable. Vegetation plans should use DNR‑approved native species and exclude invasive species.

No formal, binding votes occurred; the subcommittee’s edits are advisory and will be packaged for APC review. The committee set a follow‑up meeting (provisionally June 10) to continue the review. The APC or the county commissioners retain final authority to change or adopt the ordinance.

Next steps: staff will refine numeric distances and measurement units, draft clearer language on acceptable financial assurances and ownership transfers, and supply references (noise measurement standards and sample bond language) before the next subcommittee meeting.