Scott County planners recommend approval of Demcon anaerobic digester; Board of Adjustment OKs height variance

Scott County staff and planners recommended approval Monday of a proposal from Demcon HCI Bioenergy LLC to build an anaerobic digester and biochar production facility on a 26‑acre lot in Section 28 of Louisville Township, and the Board of Adjustment granted a related height variance for the site’s air‑quality control building.

The Planning Advisory Commission voted 6‑1 to recommend the preliminary plat and conditional use permit to the County Board after hearing a technical presentation from county staff and a detailed project presentation from Demcon. The county’s Board of Adjustment approved a separate variance to raise the maximum permitted building height from 45 feet to 65 feet to accommodate required air‑quality equipment tied to a Minnesota Pollution Control Agency (MPCA) air permit.

Why it matters: County planners and the applicant say the facility will divert organic waste from landfills, supply renewable natural gas to pipeline utilities and produce biochar as an industrial soil amendment and carbon‑sequestering product. Neighbors raised concerns about wetlands, stormwater, traffic, odors and long‑term changes to the hamlet of Lydia; township officials argued the change would help preserve the town’s tax base as other industrial areas are annexed by nearby cities.

Project overview and regulatory status Demcon proposes an anaerobic digester with associated gas upgrading and a high‑temperature biochar (gasification) stage on a reclaimed portion of an existing quarry site. Greg Wagner, principal planner for Scott County, told the commission the property is zoned I‑2 Heavy Industrial and described the parcel context: “To the west is land that’s part of the National Wildlife Refuge,” and Bridal Rock Quarry sits to the north. Wagner also noted the project team submitted an Environmental Assessment Worksheet (EAW) to the MPCA and received a negative declaration (no Environmental Impact Statement required) and that the MPCA issued an air permit in September 2024.

Demcon’s presentation (Mark…