Chapter 29 ZONING*
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
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
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
the highest vertical extension of any blades or rotors.
Interconnection. Sharing energy through the local utility grid system. This requires
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
Off-grid. An electrical system that is not connected, or is not permitted to be connected,
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
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
Shadow flicker. Alternating changes in light intensity, caused by the moving blades of
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
Wind turbine. A piece of electrical generating equipment that aids in the conversion of
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
(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
engineers certification that the monopole structure, foundation,
and design is appropriate, given local soil and climate conditions. Manufacturer certification
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 roofs structural
members. A certification from a Missouri-licensed engineer on the general design of a building-mounted
WECS shall be required.
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.
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 applicants sole expense, furnish a flicker
for City review.
(e) Procedures for permits.
(1) Permit required:
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.
for interconnection to the electric grid is independent of the approval
for the WECS building permit. If an interconnected system is planned, the applicable utilitys
interconnection requirements must also be satisfied, and no building permit shall be issued until
the building official has been provided with that utilitys 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.
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.
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.
and visual impact. No lettering, advertising, or graphics other than a
standard manufacturers 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 citys comprehensive plan.
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
manufacturers specifications. The property owner of any WECS shall maintain such system
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:
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
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
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 persons 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
(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 sites 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 propertys electric meter, noting the presence
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 WECSs 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 owners expense.
(h) Height and area regulations.
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
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
(2) Maximum height for any WECS (freestanding
or building-mounted) shall be the total
system height, defined as follows:
the R-1, R-2, R-3, R-4, RMH, and C-1 districts, forty-five (45) feet.
the C-3 district, sixty (60) feet.
the O-1 and O-2 districts, ninety (90) feet.
the C-2, M-1, M-R, and M-C districts, one hundred twenty (120) feet.
lots greater than three (3) acres, one hundred fifty (150) feet.
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
(4) Other regulations:
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.
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.
i. No part
of a WECS shall be located within or over public drainage, utility or other
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 citys standard procedures for nuisance removal may be followed at the
discretion of the building official or the officials designee.
(Ord. No. 21110, § 1, 10-17-11)
(Ord. 21110, Added, 10/17/2011)