Purpose. Health, safety, welfare, compatibility, functionality of turbines in urban areas.
(A) Definitions. For the purpose of this section the following definitions shall apply unless the context clearly indicates or requires a different meaning.
BLADE ARC.
The arc created by the edge of the rotor blade that is farthest from the center.
FALL ZONE.
The area defined as the furthest distance from the WECS tower base in which a guyed tower will collapse in the event of a structural failure.
ROTOR DIAMETER.
The diameter of the circle described by the moving rotor blades.
TOTAL HEIGHT.
The highest point, above ground level, reached by a rotor tip or any other part of the WECS.
TOWER.
A tower includes a vertical structure that supports the electrical generator or rotor blades of the WECS.
TOWER HEIGHT.
The total height of the WECS exclusive of the rotor blades.
TURBINE.
Any piece of electrical generating equipment that converts the kinetic energy of blowing wind into electrical energy through the use of airfoils or similar devices to capture the wind.
WIND ENERGY CONVERSION SYSTEM (WECS).
An electrical generating facility comprised of one wind turbine and accessory facilities that operate by converting the kinetic energy of wind into electrical energy. The energy may be used on-site or distributed into the electrical grid.
(B) Zoning district regulations. A WECS is permitted only as an interim use in Agricultural Zoning Districts and only if the WECS complies with the requirements set forth in § 155.441 and those requirements set forth below.
(1) In reviewing an application for an interim use permit for a WECS, the Planning Commission and Council may attach whatever reasonable conditions they deem necessary to mitigate anticipated adverse impacts associated with the use, to protect the value of property within the zoning district and to achieve the goals and objectives of the Comprehensive Plan. Such conditions may include increasing setbacks, relocating the WECS, or landscaped screening in order to protect views, reduce noise or other negative characteristics.
(2) A roof or building-mounted WECS is not permitted.
(3) Only a WECS utilizing horizontal axis wind turbines (OHWT) is permitted. The OHWT must have the main rotor shaft and electrical generator at the top of the tower and must be pointed into the wind.
(4) Number. Only one WECS shall be permitted per lot of record.
(5) Height. A WECS shall have a total height, including tower and rotor at its highest point, of no more than 150 feet.
(6) Yard requirements. In no case shall a WECS be located closer to the public right-of-way than any principal structure existing on the property at the time of construction of the WECS.
(7) Setbacks. A WECS shall be setback from all property lines, overhead electrical power lines, or planned right-of-way identified in the city's Transportation Plan a minimum of 1.1 times the total height of the WECS. A WECS located in the Shoreland Overlay District shall be setback a minimum of 500 feet from the ordinary high water level.
(8) Safety design standards.
(a) Engineering certification. An applicant seeking to install a WECS must provide engineering certification that the turbine, foundation, and tower design of the WECS is within accepted professional standards given site soil and climate conditions. Certification may be demonstrated by the WECS' manufacturer's engineer or another qualified engineer acceptable to the City Building Official.
(b) Rotor safety. Each WECS shall be equipped with both a manual and automatic braking device capable of stopping the WECS' operation in winds 40 mph or greater.
(9) Equipment design and performance standards.
(a) Each WECS must be mounted on a tubular, monopole type tower.
(b) Color and finish. All wind turbines and towers that are part of a WECS shall be white or grey, or a similar color approved by the Zoning Administrator. Finishes shall be matt or non-reflective.
(c) Rotor clearance. Blade arcs created by the WECS shall have a minimum of 30 feet of clearance over any structure or tree located within a 200 foot radius of the WECS.
(d) Rotor diameter. The rotor diameter of a WECS shall not exceed 50 feet.
(e) Technology standards. A WECS must meet the minimum standards of a WECS certification program recognized by the American Wind Energy Association, such as AWEA's Small Wind Turbine Performance and Safety Standard, the Emerging Technologies program of the California Energy Commission, or other third party standards acceptable to the city.
(f) Established wind resource. A WECS shall only be installed where there is an established wind resource. An established wind resource may be documented in the following ways:
1. The proposed site for the WECS has a minimum 11 MPH average wind speed at the designed hub height, as documented on the Minnesota Department of Commerce statewide wind speed maps.
2. The proposed WECS turbine has a minimum hub height of 80 feet and the blade arc is 30 feet higher, on a vertical measurement, than all structures and trees within 300 feet of the tower.
3. Providing to the city an analysis conducted by a certified wind energy installer or site assessor (North American Board of Certified Energy Professional, NABCEP, or equivalent) that includes estimates of wind speed at the WECS turbine height based on measured data, estimated annual production, and compliance with the WECS manufacturer's design wind speed.
(10) Lighting. A WECS shall not be artificially lighted, except to the extent required by the Federal Aviation Administration or other federal or state law or regulation that preempts local regulations.
(C) Plans required. Plan applications shall be accompanied by to-scale horizontal and vertical (elevation) drawings of the entire WECS and a scaled site plan. At the city's sole discretion, a current survey may be required. The site plan must show the location of the WECS tower and accessory equipment and any structures or improvements (on or offsite) located within 500 feet of the proposed WECS tower location.
(D) Noise. Each WECS shall comply with Minnesota Rules 7030, and shall not exceed 50 dB(A) when measured from the outside of the nearest residence, business, school or other inhabited structure. The audible noise from a WECS may periodically exceed allowable noise levels when wind exceeds 30 mph.
(E) Compliance with other codes. Each WECS must comply with the Minnesota State Electrical Code and must be approved by the Federal Aviation Administration and the City Building Official.
(F) Utility notification. A WECS may not be installed until the Zoning Administrator has determined that the owner of the land upon which the WECS is to be located has submitted notification to the utility company of the owner's intent to install an interconnected customer-owned generator. Off-grid systems are exempt from this requirement.
(G) Abandonment. A WECS shall be considered abandoned after one year without energy production. A WECS and its accessory facilities shall be removed to ground level within 60 days after the city has notified the owner of the land upon which the WECS is located that the city has declared the WECS abandoned.
(Ord. 1401, passed 1-28-14)