In order to balance the need for clean, renewable energy resources and the necessity to protect the public health, safety and welfare of the community, the City finds that these regulations are necessary in order to ensure that wind energy conversion systems are appropriately designed, sited and installed. (Ord. 10-003, 1-19-2010, eff. 7-1-2010)

It shall be unlawful to erect or maintain a commercial wind energy conversion system within Mason City. (Ord. 10-003, 1-19-2010, eff. 7-1-2010)

   A.   Permit Required: It shall be unlawful to construct, erect, install, alter or locate any wind energy conversion system until all required building and electrical permits have been issued and all conditions imposed by the Chief Building Official and (if applicable) the board are met. The owner/operator of any wind energy conversion system must also obtain any other permits required by other Federal, State and local agencies/departments prior to erecting the system.

   B.   Dispersed WECS; Conditional Use: A dispersed wind energy conversion system shall be allowed only as a conditional accessory use to a permitted principal or approved conditional principal use. A dispersed WECS shall not be installed and operated until a conditional use has been approved by the board and all conditions imposed by the board are met. The conditional use permit may be revoked at any time the approved system does not comply with the rules set forth in this chapter and the conditions imposed by the board.

   C.   Number Of Systems Per Zoning Lot:

      1.   Dispersed WECS: A maximum of five (5) dispersed wind energy conversion systems may be placed on any zoning lot, provided the minimum lot size and setbacks stipulated in section 12-17-4 of this chapter are met.

      2.   Small WECS: Multiple small wind energy conversion systems may be placed on a lot, but the total rated capacity of all systems shall not exceed fifty (50) kilowatts. (Ord. 10-003, 1-19-2010, eff. 7-1-2010; amd. 2017 Code)

   A.   Minimum Lot Size:

      1.   Dispersed WECS: A dispersed wind energy system shall not be erected on a zoning lot smaller than seven (7) acres. If four (4) dispersed wind energy systems are placed on the lot, the zoning lot shall measure at least ten (10) acres. If five (5) dispersed wind energy systems are placed on the lot, the zoning lot must measure at least thirteen (13) acres.

      2.   Small WECS: No minimum lot size shall apply to small wind energy conversion systems.

   B.   Maximum Tower Height: Tower height shall be measured from the ground to the top of the tower, excluding the wind turbine generator and blades.

      1.   Dispersed WECS: There shall be no maximum tower height for dispersed wind energy conversion systems.

      2.   Small WECS: The maximum tower height for small wind energy conversion systems shall be one hundred feet (100').

   C.   Setbacks:

      1.   Dispersed WECS:

         a.   The minimum distance between a dispersed wind energy conversion system and any property line shall be a distance that is equivalent to one hundred ten percent (110%) of the total system height.

         b.   A dispersed wind energy conversion system shall be set back at least seven hundred fifty feet (750') from any public right-of- way.

         c.   The board may authorize a lesser setback distance if a registered engineer licensed by the State of Iowa specifies in writing that the collapse of the system will occur within a lesser distance under all foreseeable circumstances.

      2.   Small WECS: There shall be no setback required for a small wind energy conversion system. (Ord. 10-003, 1-19-2010, eff. 7-1-2010; amd. 2017 Code)

   A.   No part of a wind energy conversion system shall be located within or over drainage, utility or other established easements, or on or over property lines.

   B.   A wind energy conversion system shall not be located in any required principal front or secondary front yard setback.

   C.   A wind energy conversion system shall be located in compliance with the guidelines of the Federal Aviation Regulations with regard to airport approach and clearance around VOR (VHF omnirange beacon) and DVOR (Doppler VHF omnirange beacon) stations.

   D.   A dispersed wind energy conversion system shall be located a minimum of one thousand feet (1,000') from the nearest inhabitable residential structure, school, hospital, park or place of worship not on property owned or controlled by the owner/operator of the dispersed wind energy system. This setback can be reduced by up to fifty percent (50%), at the discretion of the board, upon a positive determination that: (Ord. 10-003, 1-19-2010, eff. 7-1-2010; amd. 2017 Code)

      1.   A noise study, prepared by a qualified professional, demonstrates that except for intermittent episodes, the dispersed wind energy system shall not emit noise in excess of the limits established by this Code. The noise study shall include:

         a.   A description and map of the project's noise producing features, including the range of noise levels expected, and the basis of the expectation.

         b.   A description and map of the noise sensitive environment, including any sensitive noise receptors, e.g., residences, hospitals, libraries, schools, places of worship, parks, areas with outdoor workers and other facilities where quiet is important or where noise could be a nuisance within one thousand feet (1,000').

         c.   A survey and report prepared by a qualified engineer that analyzes the preexisting ambient noise (including seasonal variation) and the affected sensitive receptors located within one thousand feet (1,000').

         d.   A description and map of the cumulative noise impacts of any problem areas identified.

         e.   A description of the project's proposed noise control features and specific measures proposed to mitigate noise impacts for sensitive receptors as identified above to a level of insignificance. (Ord. 10-003, 1-19-2010, eff. 7-1-2010)

      2.   A shadow flicker model demonstrating that shadow flicker shall not fall on, or in, any existing residential structure regardless of distance from the WECS. Shadow flicker expected to fall on a roadway or a portion of a residentially zoned parcel may be acceptable if the flicker does not exceed thirty (30) hours per year and the traffic volumes are less than five hundred (500) vehicles on the roadway. The shadow flicker model shall:

         a.   Map and describe within a one thousand foot (1,000') radius of the proposed dispersed wind energy system the topography, existing residences and location of their windows, locations of other structures, wind speeds and directions, existing vegetation and roadways. The model shall represent the most probable scenarios of wind constancy, sunshine constancy, and wind directions and speed;

         b.   Calculate the locations of shadow flicker caused by the proposed project and the expected durations of the flicker at these locations, calculate the total number of hours per year of flicker at all locations;

         c.   Identify problem areas where shadow flicker will interfere with existing or future residences and roadways and describe proposed mitigation measures, including, but not limited to, a change in siting of the wind energy conversion system, a change in the operation of the wind energy conversion system, or grading or landscaping mitigation measures. (Ord. 10-003, 1-19-2010, eff. 7-1-2010; amd. 2017 Code)

The following standards are required of all small and dispersed wind energy conversion systems:

   A.   Color: The wind energy conversion system shall be white or light gray in color. Other neutral colors may be allowed at the discretion of the board. The surface shall be nonreflective.

   B.   Lighting: No lights shall be installed on the tower, unless required to meet FAA regulations.

   C.   Signs: One (1) sign, limited to four (4) square feet, shall be posted at the base of the tower. The sign shall include a notice of no trespassing, a warning of high voltage, and the phone number of the property owner/operator to call in case of emergency.

   D.   Climbing Apparatus: All climbing apparatus shall be located at least twelve feet (12') above the ground, and the tower must be designed to prevent climbing within the first twelve feet (12').

   E.   Fence: To limit access to the tower, a fence six feet (6') high with smooth side to the outside, with no more than one inch (1") gaps and a locking portal shall be placed around the wind energy conversion system, unless the system is a small WECS located within a fenced or otherwise secured yard, or is a small WECS mounted on a rooftop.

   F.   Maintenance: Facilities shall be well maintained in an operational condition that poses no potential safety hazard.

   G.   Displacement Of Parking Prohibited: The location of the wind energy conversion system shall not result in the net displacement of required parking as specified in this title.

   H.   Restriction On Use Of Electricity Generated: A wind energy conversion system shall be used exclusively to supply electrical power for on site consumption, except that when a parcel on which a wind energy conversion system is installed also receives electrical power supplied by a utility company, excess electrical power generated by the wind energy conversion system and not presently needed for on site use may be used by the utility company in accordance with section 199, chapter 15.11(5) of the Iowa Administrative Code.

   I.   Clearance Of Blade Aboveground: No portion of a small wind energy conversion system blade or rotor shall extend within twenty feet (20') of the ground. No portion of a dispersed wind energy conversion system blade or rotor shall extend within fifty feet (50') of the ground. No blades or rotors may extend over parking areas, driveways or sidewalks.

   J.   Automatic Overspeed Controls: All wind energy conversion systems shall be equipped with manual and automatic overspeed controls to limit the blade rotation speed to within the design limits of the wind energy conversion system.

   K.   Noise: Except during short term events including utility outages and severe wind events, a wind energy conversion system shall be designed, installed and operated so that the noise generated does not exceed the maximum noise levels established by this Code.

   L.   Electromagnetic Interference: All blades shall be constructed of a nonmetallic substance. A wind energy conversion system shall not be installed in any location where its proximity with existing fixed broadcast, retransmission, or reception antenna for radio, television, wireless phone or other communication systems would produce electromagnetic interference with signal transmission or reception. A wind energy conversion system shall not be installed in any location along the major axis of an existing microwave communications link where its operation is likely to produce electromagnetic interference in the link's operation. If it is determined that the wind energy conversion system is causing electromagnetic interference, the operator shall take the necessary corrective action to eliminate this interference, including relocation or removal of the facilities, subject to the approval of the board (in the case of a dispersed WECS) or the Administrative Officer (in the case of a small WECS). The board may revoke a conditional use permit granting a dispersed wind energy conversion system if electromagnetic interference from the system becomes evident.

   M.   Interconnection: The wind energy conversion system, if interconnected to a utility system, shall meet the requirements for interconnection and operation as set forth by the utility and the Iowa Utilities Board.

   N.   Wind Access Easements: The enactment of this chapter does not constitute the granting of an easement by the City. The owner/operator shall provide covenants, easements, or similar documentation to assure sufficient wind to operate the wind energy conversion system unless adequate accessibility to the wind is provided by the site.

   O.   Insurance: The owner/operator of a wind energy conversion system must demonstrate adequate liability insurance.

   P.   Complaint Resolution: The owner/operator of a dispersed wind energy conversion system shall develop a process to resolve complaints from nearby residents. The process shall use an independent mediator or arbitrator and include a time limit for acting on a complaint. The owner/operator shall make every reasonable effort to resolve any complaint.

   Q.   Removal: If the wind energy conversion system remains nonfunctional or inoperative for a continuous period of one (1) year, the system shall be deemed to be abandoned and shall constitute a public nuisance. The owner/operator shall remove the abandoned system at their expense. Removal of the system includes the entire structure including foundations, transmission equipment and fencing from the property. Nonfunction or lack of operation may be proven by reports from the interconnected utility. The owner/operator and successors shall make available to the Administrative Officer all reports to and from the purchaser of energy from the wind energy conversion system if requested. If removal of towers and appurtenant facilities is required, the Administrative Officer shall notify the owner/operator. If the City removes a tower and appurtenant facilities, it may sell the salvage to defray the cost of removal. Any remaining cost shall be reimbursed by the owner/operator.

   R.   Right Of Entrance: By the acceptance of a conditional use permit, the owner/operator of a dispersed WECS grants permission to Mason City to enter the property to remove the wind energy conversion system pursuant to the terms of the conditional use permit and to assure compliance with the other conditions set forth in the permit. (Ord. 10-003, 1-19-2010, eff. 7-1-2010; amd. 2017 Code)

Approval or denial of an application for a conditional use permit to allow construction of a dispersed wind energy conversion system shall be made by the board as outlined in chapter 5 of this title.

   A.   Application: An application for a conditional use permit for a dispersed wind energy conversion system shall be made on the forms provided by the Administrative Officer and shall be accompanied by the following information:

      1.   A site plan showing the following:

         a.   Complete property dimensions.

         b.   Location and full dimensions of all buildings existing on property including exterior dimensions, height of buildings and all uses on property. Location and full dimensions of all buildings within two hundred feet (200') of the property including exterior dimensions, height and uses on property.

         c.   Location and dimensions of any other natural or manmade features within two hundred feet (200') of the property such as trees, ridges, highways, streets, bridges and underpasses.

         d.   Proposed location of tower including height, setbacks and distance to all buildings on the property and all buildings within two hundred feet (200') of the base of the tower.

      2.   A map showing the location of the tower and all property within a one thousand foot (1,000') radius of the base of the tower, showing lot lines and the location of all habitable residential structures, schools, hospitals, parks, or places of worship within that radius, along with the distance to such functions from the base of the proposed tower, or showing that none of the above listed functions are located within the indicated radius.

      3.   Drawings, to scale, of the structure, including the tower, base, wind turbine generator, rotors, footings and guywires, if any, including dimensions necessary to show compliance with the requirements of this chapter. The drawings and any necessary calculations shall be certified by a licensed engineer as meeting the requirements of the Mason City Building Code.

      4.   Line drawing of the electrical components in sufficient detail to allow for a determination that the manner of installation will meet the Mason City Electrical Code.

      5.   Certification from a licensed engineer or qualified person that the rotor and overspeed control have been designed for the proposed use on the proposed site.

      6.   Evidence that the applicant has notified the utility that the customer intends to install an interconnected customer owned generator, and that the generator meets the minimum requirements established by the utility and the Iowa Utilities Board. Off grid systems shall be exempt from this requirement.

      7.   Evidence from a qualified individual that the site is feasible for a wind energy conversion system, or that covenants, easements and other assurances to document sufficient wind to operate the wind energy conversion system have been obtained.

      8.   Evidence that the proposed wind energy conversion system will comply with applicable Federal Aviation Regulations, including any necessary approvals from the Federal Aviation Administration.

      9.   Evidence that the applicant can obtain and maintain adequate liability insurance for the facility.

      10.   A noise study, if applicable.

      11.   A shadow flicker model, if applicable.

      12.   A site specific electromagnetic compatibility analysis assessing the impact to existing microwave bands with frequencies between nine hundred megahertz (900 MHz) and forty gigahertz (40 GHz). The report shall include the following elements:

         a.   An inventory of existing microwave links operating in the nine hundred megahertz (900 MHz) to forty gigahertz (40 GHz) range within ten (10) miles of the dispersed wind energy system.

         b.   An obstruction analysis of these links including the Fresnel zone of the microwave path.

         c.   Any recommended mitigation actions necessary to ensure that the dispersed wind energy system will not obstruct the first Fresnel zone.

         d.   An inventory of licensed television stations in a one hundred fifty (150) mile radius of the proposed dispersed wind energy system that are providing programming services to Mason City.

         e.   A baseline measurement of signal strength and picture quality.

         f.   Recommended means of mitigation, avoidance or remedy to minimize or eliminate signal degradation or interference.

      13.   Any other evidence or information as required by the Administrative Officer or board.

      14.   An application fee plus charge for each additional public notice sign.

   B.   Public Notice: The Administrative Officer shall cause notice to be published in the time and manner set forth in section 12-5-5 of this title. Notices shall be mailed to the owners of all properties within one thousand five hundred feet (1,500') of the zoning lot on which the dispersed WECS would be constructed. (Ord. 10-003, 1-19-2010, eff. 7-1-2010; amd. 2017 Code)