Permitting

Noise

Wind turbine noise and associated impacts are some of the more important issues facing local authorities in permitting wind projects. Regulations in this category generally refer to a decibel measurement of the sound emissions from a turbine, and increasingly local authorities are asked to consider the concerns of the community in setting these regulations. Many Minnesota counties refer to the state noise standards, while some impose additional requirements and measurements on the appropriate levels of sound from wind turbines in their community.

Lighting

Commercial wind turbines are installed on tall towers and proper lighting is required for the safety of any nearby aviation facilities. There are also concerns with the impacts different lighting mechanisms may have on local communities and wildlife. All wind projects must comply with any applicable Federal Aviation Administration (FAA) requirements regarding appropriate lighting, and many county permitting regulations refer to or incorporate those requirements.

Height

Permitting regulations in this category refer to the maximum total height of a wind turbine allowed. Current wind turbine designs are the result of many years of research and development in establishing the ideal height of the tower and blade lengths in order to most efficiently capture the wind resource. Counties may chose to regulate in this category for a variety of reasons, including public safety or aesthetics.

Electrical

These permitting regulations address the feeder lines and communications lines used to connect the wind turbines to the other project infrastructure, in order to minimize the visual impact from these components. Currently, the common industry practice currently is to bury these electric lines; however there may be certain geological conditions that make burying these lines impractical.

Decommissioning

Decommissioning as a permitting regulation refers to the process for removing a wind energy conversion system once the project has reached its end. There are a variety of methods used to regulate this area of wind development, from requiring a bond or financial guarantee before a permit is issued to simply requiring a written plan for removing the turbine and associated components.

Clearance

These permitting regulations refer to the minimum distance the tips of the blade must be above the ground or other nearby obstacles. This ensures both safety for structures and beings near operating turbines, as well as promoting the most efficient use of the wind resource.

Brakes

Permitting requirements for safety equipment generally refer to the presence of braking systems in the event that the rotor spins too fast in high wind or to help prevent a catastrophic failure. Most modern turbines today include, in the technology design, both automatic and manual braking options to slow or stop the rotor altogether.

Appearance

These permitting regulations are designed to reduce the visual impact of a wind turbine, as well as minimize the impact on wildlife, especially birds. The most common requirements are for a white or grey color, and non-reflective finishes to minimize glare.

Access

This permitting regulation category refers to the standards that apply to the service roads or construction roads of a wind project. Construction equipment for large, commercial-scale wind turbines can exceed the allowable weight and size for some rural roads and therefore counties may impose certain requirements in this category.

Permitting Wind Projects in Minnesota

Proposed wind energy projects in Minnesota with a total nameplate capacity of 5MW and greater are subject to state regulation while projects under that threshold are subject to local regulation. For more information about the state permitting requirements and process, visit MN Public Utilities Commission.

Additionally, counties may elect to assume the authority to regulate wind projects up to 25MW. In order to make this election, a county must submit a letter of their intention to the Minnesota Public Utilities Commission along with copies of any regulations adopted that are more stringent than the state guidelines.

Category State Minimum Setback
Wind Access Buffer (setback from land not under permittee's control) 3 rotor diameters on east-west axis and 5 rotor diameters on north-south axis
Internal turbine spacing 3 rotor diameters crosswind by 5 rotor diameters downwind
Noise Distance sufficient to meet state standard of 50dBA at night
Homes At least 500 ft and sufficient distance to meet noise standard
Public Roads 250 ft
Meteorological Towers 250 ft
Wetlands, Native Prairie, Sand and Gravel Operations Variance required for approval

 

 

Minnesota County Wind Ordinances

As of April 1, 2010, there are 87 counties in Minnesota, of which 61 had specific wind energy conversion system ordinances applicable to commercial scale wind projects. Our review of these 61 county ordinances currently regulating wind energy conversion systems in Minnesota focused on 15 specific categories:

Common categories of local regulation of wind turbines  # of MN Counties
Identification of certain zoning districts that are allowed to have wind turbines 44
Whether a permit is required 61
Setbacks, including those from neighboring properties, public roads and right of ways, and conservation lands 59
Density of turbines or internal turbine spacing and distance 18
Height requirements that regulate the total maximum allowed height of a wind turbine in the county 21
Clearance between the ground and the blades 37
Standards for creating and maintaining access roads 4
Regulations on treatment of feeder and communication lines, generally requiring them to be buried 44
Requirement of brakes or other safety equipment in the turbine to prevent catastrophic failures 24
Standards for color, finish and overall appearance of the wind turbines 54
Signs for safety and identification of owner or other emergency contact 57
Decommissioning requirements 53
Identification of potential for signal and broadcast interference 41
Maximum noise thresholds 52
Regulations on lighting of the turbines 52

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