Mortenson, Kimley Horn and Minnesota Power outline proposed four‑building data center campus near Arrowhead substation in Hermantown

Dan Lesser of Mortenson Development told the Hermantown City Council that the presentation would provide technical detail to accompany a second reading of rezoning for a proposed data center campus east of Minnesota Power’s Arrowhead substation.

Brian Werteman, an engineer with Kimley Horn, said the site is at the southwest corner of Midway Road and Morris Thomas Road and described a campus plan with four data center buildings of about 300,000 square feet each (40–50 feet tall), two roughly 30,000‑square‑foot office buildings, and a 45,000‑square‑foot office/warehouse near the primary entrance. Werteman said the buildings are sited to preserve existing wetlands, particularly a substantial wetland complex in the southeast corner near a trout stream.

The team said it completed multiple studies informing the design: a field wetland delineation coordinated with city, county, the Board of Water and Soil Resources (BWSR) and the Minnesota Department of Natural Resources; a threatened and endangered species review; a cultural and archaeological survey with the Fond du Lac tribe; a tree survey; a Phase I environmental site assessment; and noise modeling. "These are critical pieces of our local and national infrastructure," Lesser said in explaining why data centers are being proposed.

On water use, Kimley Horn presented modeled average daily demand at full campus build‑out of 30,000 to 50,000 gallons per day, which the consultants said is roughly equivalent to the demand of about 160 single‑family residential units and would represent an estimated 2%–5% of Hermantown's existing water system at full build‑out. The presenters said those figures were studied up to 50,000 gallons per day in the previously completed AUAR.

Traffic modeling estimated about 1,920 daily trips at steady state with an AM peak of about 290 trips; construction peak hour estimates were about 360–390 trips. Werteman summarized recommended roadway work tied to those findings: turn‑lane construction at the Morris Thomas access, a traffic signal at Midway Road and Morris Thomas Road, and an added westbound turn lane on US Highway 2 at Saint Louis River Road.

Jason Scrimshaw, a civil engineer at Kimley Horn, addressed acoustics and said Minnesota noise standards set by the Minnesota Pollution Control Agency are 60 decibels for daytime and 50 decibels at night near residential land uses. "We have conservatively designed our site and modeled our noise assessment to comply with 50 decibels in either daytime or nighttime operations," Scrimshaw said, and the team showed contours and proposed mitigation including an earthen berm with a noise wall on the eastern perimeter and a noise wall on the north perimeter.

Scrimshaw also summarized lighting controls, saying the project would follow Hermantown's lighting standards without seeking variances by using larger setbacks, downlighting and cutoff shields to prevent glare or light spill onto neighboring parcels. He described stormwater basins designed as biofiltration systems with pretreatment structures and filtration media to remove suspended solids and phosphorus and to manage runoff temperature in discharge toward the trout stream; he said basins meet city and state rate and volume control requirements.

The presenters noted more than 100 feet of existing elevation change across the site and said design and plantings are intended to use topography and a robust perimeter landscape plan to provide visual screening over a 1–30 year planting growth timeline.

Julie Pierce, vice president of strategy and planning for Minnesota Power, explained the electric interconnection process and regulatory context. Pierce said Minnesota Power receives many grid‑connect requests and conducts months‑long interconnection studies that assess local, county, regional and multi‑state impacts; if system upgrades are needed, the interconnection customer pays for them. She said interconnection is formalized through an agreement filed with the Federal Energy Regulatory Commission (FERC). "That study ensures that the power consumption by the new customer does not have negative impact and can be accommodated," Pierce said.

Pierce described Minnesota's long‑range Integrated Resource Plan overseen by the Minnesota Public Utilities Commission and said Minnesota Power customers in the region now receive roughly 50%–60% renewable supply on the system with plans to reach about 95% by 2035. She also referenced 2025 state legislation specific to data centers, saying the law requires that connecting new data centers not harm existing customers and that new facilities deliver additional benefits; she described the statute as part of the permitting and interconnection environment the council should consider.

No formal motion or vote on the rezoning was recorded during the presentation; the team concluded by offering to answer council and planning staff questions at upcoming hearings.