Section 29-21.5 Wind Energy Conversion Systems.

    (a)    Purpose and intent.  It is the goal of the city of Columbia to enable citizens to pursue alternative and sustainable energy sources for their homes. In accordance with this goal, the city finds that it is in the public interest to encourage alternative energy systems, particularly wind energy conversion systems (WECS), that have a positive impact on energy production and conservation while not adversely impacting the community.

    (b)    Definitions.  As used in this section, the following terms shall have the meanings and usages indicated.

     Ambient sound level. The sound pressure level exceeded ninety (90) percent of the time, or L90, at a given location.  Also, the amount of background noise at a given location prior to the installation of a WECS, which may include, but is not limited to, traffic, machinery, general human activity, and the interaction of the wind with the landscape. Ambient sound level is measured on the Decibel dB(A) weighted scale as defined by the American National Standards Institute (ANSI).

     Axis. The plane on which a rotor or other wind-harnessing mechanism rotates. City regulations do not differentiate between horizontal- and vertical-axis WECS.

     Decibel. The unit of measure used to express the magnitude of sound pressure and sound intensity.  Commonly abbreviated as dB(A).

     Fall zone. The hypothetical area into which a tower and wind turbine could collapse in the event of a structural failure.

     Feeder line. Any power line that carries electrical power from one or more wind turbines or individual transformers associated with an individual wind turbine to the point of interconnection with the electric power grid.  In the case of interconnection with the high voltage transmission systems, the point of interconnection shall be the substation serving the WECS.

     Generator nameplate capacity/nameplate generating capacity (installed). The maximum rated output of a generator, prime mover, or other electric power production equipment under specific conditions designated by the manufacturer.  Installed generator nameplate capacity is commonly expressed in kilowatts (kW) or megawatts (MW) and is usually indicated on a nameplate physically attached to the generator.

     Height, total system.  The height above grade of the WECS, including the generating unit and the highest vertical extension of any blades or rotors.

     Interconnection.  Sharing energy through the local utility grid system.  This requires an approved interconnection agreement with the pertinent utility provider serving the site, e.g. City of Columbia Water and Light, Boone Electric Cooperative, or Central Electric Power Cooperative.

     Off-grid.  An electrical system that is not connected, or is not permitted to be connected, to any utility distribution and transmission facility or to any building or structure that is connected.

     Property line.  For the purposes of this section only, the boundary line of the area over which the entity applying for WECS permit has legal control for the purposes of installation of a WECS.  This control may be attained through fee title ownership, easement, or other appropriate contractual relationship between landowners.

     Rotor.  An element of a WECS that acts as a multi-bladed airfoil assembly, thereby directly extracting through rotation the kinetic energy of wind.

    Rotor diameter.  The diameter of the circle described by the rotor blades. See  also the definition for “s wept area.”

     Shadow flicker.  Alternating changes in light intensity, caused by the moving blades of a wind energy conversion system, that casts moving shadows on the ground and stationary objects.

     Sound pressure level.  The sound measurement commonly reported in decibels (dB(A)).

     Swept area.  The diameter of the least circle encompassing all blades for a WECS. Also any and all portions of overhanging blades, turbines, or attachments that oscillate, rotate or otherwise move, which are not part of the fixed structural elements of the wind energy conversion system, including those on vertical axis WECS.  See also the definition for “rotor diameter.”

     Tower.  The vertical component of a WECS that elevates and supports the wind turbine generator, rotor blades, and other equipment above the ground.

     Wind energy conversion system (WECS).  The configuration of components including the base, tower, generator, rotor blades and related equipment to convert the kinetic energy of wind into electrical energy (e.g. windmill or wind turbine).  A wind energy conversion system which has a nameplate rated capacity of up to one hundred (100) kilowatts and is incidental and subordinate to a principal use on the same parcel.

     Wind energy conversion system, building-mounted.  A WECS that is securely fastened to any portion of a principal structure in order to achieve desired elevation, whether attached directly to the principal structure or attached to a tower structure which is in turn fastened to the principal structure.  A building-mounted WECS is not a minor projection, as defined in section 29-26(b) of the City Code.

     Wind energy conversion system, co-located.  A wind energy conversion system that is mounted on a tower or pole structure which serves another primary purpose, such as a flagpole. Co-located systems are permitted per the rules of this chapter, so long as a principal use or structure is located on the subject parcel.

     Wind energy conversion system, commercial.  A wind energy conversion system which is intended to produce electricity for sale to a rate-regulated or non-regulated utility or for use off site.  For the purpose of this ordinance, a commercial WECS has a total nameplate generating capacity equal to or greater than 100 kW.

     Wind energy conversion system, freestanding.  A wind energy conversion system which is elevated by means of a monopole tower and is not located on another supporting structure. Guyed, lattice, or other non-monopole style towers shall not meet this definition.

     Wind energy conversion system, noncommercial.  A WECS of less than 100 kW in total nameplate generating capacity that is not operated on a for-profit basis.  A WECS that is interconnected with the pertinent electric utility or that receives credits or rebates for energy transmitted to the power grid is not by that reason alone operated on a for-profit basis.

     Wind energy conversion system, small.  A WECS of less than 10 kW in total nameplate generating capacity.

     Wind turbine.  A piece of electrical generating equipment that aids in the conversion of the kinetic energy of wind into electrical energy.

    (c)    Permitted uses.

    (1)     One (1) noncommercial wind energy system (WECS) shall be allowed as an accessory use to a permitted principal use on the same lot, on lots meeting setback and fall zone requirements [see subsection (h), height and area regulations], in districts R-1, R-2, R-3, R-4, RMH, PUD, and A-1.

    (2)    Two (2) noncommercial WECS shall be allowed as accessory uses to a permitted principal use on the same lot, on lots meeting setback and fall zone requirements [see subsection (h)], in districts O-1, O-2, O-P, C-1, C-2, C-3, C-P, M-R, M-C, M-P, M-1.

    (3)    Notwithstanding subsections (1) and (2), WECS shall not be permitted uses within the boundaries of the Downtown Community Improvement District as defined in the petition approved by Ordinance No. 20866.

    (4)    Commercial WECS are not allowed in any zoning district.

    (d)    Conditional uses.

    (1)    A WECS shall be allowed only after the issuance of a conditional use permit in all locations where WECS are not allowed as permitted uses.  Where one or two WECS are allowed as permitted uses, additional WECS shall be allowed only after the issuance of a conditional use permit.

    (2)    Applications for conditional use permits shall be filed and processed in the manner established in section 29-23.  In addition, the application shall include the following information:

        a.     The name(s) of project applicant(s).

        b.     The name(s) of the project owner(s).

        c.     The legal description and address of the project.

        d.    A description of the project including: number, type, nameplate generating capacity, tower height, rotor diameter, and total system height of all wind turbines and means of interconnecting with the electrical grid (if applicable) and an anticipated construction schedule.

        e.     A site plan, drawn to scale, including the location of property lines, wind turbine(s), electrical wires, interconnection points with the electrical grid, all related accessory structures, and physical features and land uses of the project area, both before and after construction of the proposed project.  The site plan shall include:

    1.    The project area boundaries;

    2.    The location, height, and dimensions of all existing and proposed structures;

    3.    The location and dimensions of all temporary and permanent on-site roads or drives;

    4.    Existing topography, and

    5.    All new aboveground infrastructure related to the project.

        f.     A Missouri-licensed engineer’s certification that the monopole structure, foundation, and design is appropriate, given local soil and climate conditions.  Manufacturer certification and specification sheets may, at the discretion of the Building Official, be used in place of engineering certification, if these provide sufficient information on the installation of the monopole (e.g. size and depth of hole to dig, type of soil or bearing needed to support the pole and turbine).  For building-mounted WECS, a written structural analysis from an engineer or contractor determining that installation of a WECS will not cause damage to the structure and that the WECS design is suitable for the structure based on the analysis of the roof’s structural members.  A certification from a Missouri-licensed engineer on the general design of a building-mounted WECS shall be required.

        g.     Documentation of land ownership or legal control of the property.

        h.     A copy of the interconnection agreement application with the applicable utility if connecting to the grid.

        i.     Those WECS that are not connected to the electric grid shall identify the location of any battery or other storage device.

        j.     Copy of the shadow flicker analysis, if required.  This shall apply only to systems greater than 10kW in nameplate generating capacity.  No WECS shall be installed and operated in a manner that causes shadow flicker to fall on or in any residential dwelling existing at the time the application to install a WECS is received by the city.  The applicant has the burden of proving that this effect does not have significant adverse impact on neighboring or adjacent uses, either through siting or mitigation.  Shadow flicker expected to fall on an adjacent parcel or roadway may be acceptable if the flicker does not exceed thirty (30) hours per calendar year.  If such flicker is likely, the applicant shall, at the applicant’s sole expense, furnish a flicker study for City review.

    (e)    Procedures for permits.

    (1)     Permit required:

            a.     It shall be unlawful to construct, erect, install, alter or locate any WECS within the city of Columbia, unless a building permit has been obtained.  The building permit may be revoked by the building official any time the approved system does not comply with the rules set forth in this section.

            b.     Authorization for interconnection to the electric grid is independent of the approval for the WECS building permit.  If an interconnected system is planned, the applicable utility’s interconnection requirements must also be satisfied, and no building permit shall be issued until the building official has been provided with that utility’s written authorization.

    (2)     Procedures for permits.  Building and, if necessary. conditional use permits and variances shall be applied for and reviewed under the procedures established in this chapter, except where noted below.  The director of community development, upon written request of the applicant, may waive any of the submittal requirements that the director deems not applicable after reviewing the request.  Applicants desiring such a waiver shall provide supporting documentation from a licensed engineer justifying the waiver.  The director may also require additional information as minimally needed to determine compliance with this Code.

            a.     The application for all WECS building permits shall include the information found in subsection (d)(2).

    (f)    General requirements and construction.

    (1)    Tower.  Only monopole towers are permitted for freestanding WECS.  Guyed or any other types of towers are not permitted.

            a.     Color and surface.  Freestanding WECS shall be a neutral color such as white or light gray.  Supporting structures for building-mounted WECS shall match the color of the building on which they are mounted. Surfaces of the WECS and building-mounted supporting structures shall be a non-reflective, matte finish.

            b.     Signage and visual impact.  No lettering, advertising, or graphics other than a standard manufacturer’s insignia shall be on any part of the tower, hub, or blades.  No other signage or message may be displayed, other than for safety or apparatus identification (e.g. nameplate, serial number or emergency instructions).  The applicant shall avoid state or federal scenic areas and significant visual resources listed in the city’s comprehensive plan.

            c.     Climbing apparatus.  The tower must be designed to prevent climbing within the first ten (10) feet.

    (2)     Lighting.  No lights shall be installed on the tower, unless required to meet Federal Aviation Administration (FAA) guidelines, where lighting intensity and frequency of strobe shall adhere to requirements established by FAA permits and regulations.  Red strobe lights are preferred for nighttime illumination and to reduce impacts on migrating birds.  Red pulsating incandescent lights shall be prohibited unless required by the FAA.

    (3)     Compliance.  All WECS equipment and connections must adhere to all applicable local and state regulations and relevant national and international codes.  In case of noncompliance, the applicant may be required to hire outside inspectors as deemed necessary by the building official or Board of Adjustment.

    (4)     Maintenance.  Facilities shall be installed and maintained in accordance with manufacturer’s specifications.  The property owner of any WECS shall maintain such system in a safe and attractive manner, including replacement of defective parts, painting, cleaning, and other acts that may be required for the maintenance and function of such a system.  Failure to maintain the WECS may result in enforcement action including, but not limited to, citations, fines, or revocation of permits in accordance with this code.

    (5)     Noise, vibration, and sound pressure level.  A WECS shall be designed, installed and operated so that any noise or vibration has minimal impact on adjacent properties.  A WECS shall not exceed 55 dB(A) at any adjacent property line.  This sound pressure level may be exceeded during short-term events such as utility outages or severe wind storms.  If the ambient sound level for the WECS location exceeds 55 dB(A), the maximum standard shall be ambient dB(A) plus 5 dB(A).  No WECS shall emit low frequency sound at or below 20 Hertz.  The process for reporting and investigating a noise complaint is as follows:

            a.     Upon written notification of a complaint of excessive noise, the building official or designated representative of the community development department (the “enforcing person”), shall record the filing of such complaint and promptly investigate it.  If noise levels are determined to be in excess of the maximum standard, the enforcing person shall require the property owner to perform ambient and operating decibel measurements at the nearest point from the wind turbine to the property line of the complainant and to the nearest off-site, inhabited residence.

            b.     If the noise levels are found to have exceeded the allowable limit, the enforcing person shall notify, in writing, the owner of the WECS site to correct the violation.  If the noise violation is not remedied within thirty (30) days, the WECS shall remain inactive until the noise violation is remedied, which may include (but is not limited to) relocation or removal at the owner’s expense.

            c.     If it is determined that maximum noise limits have not been exceeded, notice in writing shall be provided to the person who has filed such complaint and the owner of the WECS property stating that no further action is required, within twenty-one (21) days of the receipt of the request. Any person aggrieved by the decision may appeal the decision to the Board of Adjustment in accordance with section 29-31.  Any such appeal must be filed within thirty (30) days of receipt of the enforcing person’s decision.

    (6)     Interconnection and utility considerations.  The applicant shall notify and apply with the appropriate electric utility in making a WECS application to install an interconnected, customer-owned WECS.  The WECS shall meet the requirements for interconnection and operation as set forth by the utility, and shall not be interconnected to any utility-operated power line or by any other means of conveyance until so authorized by the utility.  Interconnected WECS shall require the approval of the applicable utility before receiving permits from the city.  Off-grid (not connected to the utility) systems shall be exempt from this application requirement.  A response from the utility is not required to approve or deny an off-grid WECS application.

    (7)     Restriction on use of electricity generated.  A WECS shall be used exclusively to supply electrical power to the owner for on-site consumption, except that excess electrical power generated by the WECS and not presently needed for use by the owner may be used by the utility in accordance with laws and regulations governing interconnection and utility approval.

    (8)     Feeder lines.  All communications and feeder lines installed as part of a WECS shall be buried where feasible.

    (9)    Displacement of parking and landscaping prohibited.  The location of the WECS shall not result in the net loss of required parking or landscaping as specified elsewhere in the zoning code.

    (g)    Safety design requirements and standards.

    (1)     A WECS shall have automatic braking, governing, and a feathering system to prevent uncontrolled rotation or over-speeding.  All WECS shall have lightning protection and shall comply with FAA standards.  The system shall also be capable of stopping power generation in the event of a power outage so as to prevent back-feeding of the grid.

    (2)    A clearly marked and easily accessible power shut off/disconnect will be required as determined by the building official.  Any battery or energy storage device will be clearly marked and a sign indicating the presence of such device(s) shall be posted at the site’s electric meter.

    (3)    No portion of the WECS swept area shall be closer than twenty (20) feet to the ground. The swept area shall extend no closer than twenty (20) feet horizontally to the nearest tree, structure, or aboveground utility facility.  No WECS shall be constructed so that any part thereof can extend within twenty (20) feet laterally of an overhead electrical power line (excluding secondary electrical service lines or service drops).

    (4)    A sign or signs shall be posted on the tower, transformer and substation warning of high voltage.  A sign shall also be posted at the property’s electric meter, noting the presence of a WECS and any battery system.  Signs with emergency contact information shall also be posted on the turbine, or at another suitable point, such as the entrance to the WECS’s service area.

    (5)    No WECS installation shall cause electromagnetic interference.  If interference is established, the building official shall notify the owner of the property in writing to correct the violation.  If the interference is not remedied within thirty (30) days, the WECS shall remain inactive until the interference is remedied, which may include, but is not limited to, relocation or removal at the WECS owner’s expense.

    (h)    Height and area regulations.

    (1)     Setbacks:

            a.     The minimum distance between any freestanding WECS and any property line shall be the distance equivalent to the fall zone, which is ninety (90) percent of the total system height.  No part of the fall zone shall cross an adjacent property line. The setback shall be measured from the property line to the point of the WECS structure closest to the property line.

For building-mounted WECS, no part of the fall zone shall cross an adjacent property line.  The fall zone for a building-mounted WECS shall be fifty (50) percent of the height as measured from the lowest attachment to the building/structure to the highest point of the blades or rotors.

The fall zone shall be entirely contained on the subject parcel.  In no case may the fall zone radius include an overhead electric power line.  The setback from underground electric distribution lines shall be at least five (5) feet; the fall zone radius may include the underground line(s).  Section 29-26, regarding allowable minor projections into required setbacks, is not applicable.

    (2)     Maximum height for any WECS (freestanding or building-mounted) shall be the total system height, defined as follows:

            a.    In the R-1, R-2, R-3, R-4, RMH, and C-1 districts, forty-five (45) feet.

            b.    In the C-3 district, sixty (60) feet.

            c.    In the O-1 and O-2 districts, ninety (90) feet.

            d.    In the C-2, M-1, M-R, and M-C districts, one hundred twenty (120) feet.

            e.    For lots greater than three (3) acres, one hundred fifty (150) feet.

            f.    In all planned districts, height shall be as proposed in the statement of intent, subject to review by the planning and zoning commission and approval by the city council.

        Maximum height may be exceeded, subject to approval of a conditional use permit by the board of adjustment.  The applicant must demonstrate that additional height is needed and that the benefits of the taller WECS do not increase any adverse impacts.

        Note: For lots in the A-1 zoning district, a maximum height of seventy-five (75) feet is allowed for windmills on agriculturally-used parcels under current zoning district standards.  This standard shall apply to all WECS applications on parcels of three (3) acres or fewer in the A-1 district.

    (4)    Other regulations:

            a.     WECS and their associated outbuildings and cabinets shall meet all setback requirements for primary structures for the zoning district in which the WECS is located. A WECS and its associated outbuildings and accessories shall not be located forward of the principal structure on a lot.

            b.     No other apparatus or mechanical and electronic equipment, such as telecommunication antennas, microwave dishes, or satellite dishes, shall be attached to a WECS tower or its associated components such as the nacelle.

            c.    Location:

        i.     No part of a WECS shall be located within or over public drainage, utility or other established easements.

        ii.     No WECS shall be constructed, altered, or maintained so as to project above any of the airspace surfaces described in FAR Part 77 of the FAA guidance on airspace protection.

        iii.    No part of the WECS, including the swept area, shall be within or overhang any portion of the property that is within a required building setback.

    (i)    Discontinuation and decommissioning.  A WECS shall be considered abandoned after six (6) months without energy production, unless a plan is developed and submitted to the enforcing person outlining the steps and schedule for returning the WECS to service.  All WECS and accessory facilities shall be removed in their entirety within ninety (90) days of abandonment.  If this is not done, the city’s standard procedures for nuisance removal may be followed at the discretion of the building official or the official’s designee.

(Ord. No. 21110, § 1, 10-17-11)


(Ord. 21110, Added, 10/17/2011)