|
There has been an increasing interest in the past year, both
locally and statewide, in alternative energy sources. At a
local level, and especially in rural counties, this idea has
most recently manifested itself in the proliferation of wind
energy systems such as small wind turbines, or windmills, as
a viable independent energy source for personal (i.e.,
private and/or non-commercial) use. Since these systems are
becoming more popular among citizens, local governments
statewide have started to consider the land use policy
questions that are presented by wind turbines, as well as
the regulatory challenges they pose to both the Virginia
Uniform Statewide Building Code and local zoning ordinances.
Among local governments in Virginia, Rockingham County was
the first to implement local zoning regulations for wind
energy in 2004; more recently, Halifax County passed Zoning
Ordinance language addressing the use of personal Wind
Energy Systems. Many other jurisdictions are in the process
of reviewing the issue (See Attachment 1 for
Ordinances/Articles related to other Jurisdictions).
In Fauquier County, staff has received several inquiries
throughout 2008 regarding individuals seeking to erect wind
turbines on their property for personal use and, in October
2008, approved the first two permits for personal windmills
in the rural zoning districts. While there is no specific
language regarding windmills in the current Zoning Ordinance
regulations, the general provisions found in Article 2 and
Article 6 do address accessory uses and structures in
general terms. As a matter of interpretation, staff relied
on language found in Section 2-506 of the Ordinance, which
states that “the height limitations of this ordinance shall
not apply to barns, silos, residential chimneys, spires,
cupolas, elevator penthouses, domes, flagpoles, birdhouses,
flues, monuments, radio towers, television antenna or
aerials, water towers, water tanks, transmission towers and
cables, smoke stacks, air conditioning units or other
similar roof structures and mechanical appurtenances.” With
respect to setbacks, staff relied on the existing location
regulations for accessory structures found in Section 6-105,
requiring that any structure over seven (7) feet in height
meet the required side yard setbacks for the zoning district
in which it is located and a rear yard setback equal to the
overall height of the structure. In both cases, the subject
properties were located in the Agricultural (RA) District
and consist of more than five (5) acres. In addition, both
applicants were applying for approval of the same structure,
a Skystream windmill that is approximately 54 feet in
height, measured from the lowest point of the finished grade
to the uppermost projection of the arc of the blades on the
turbine itself. Although the minimum side yard setback of
the RA District is only 25 feet, in both cases the applicant
agreed to staff’s request that the windmills be located a
minimum of 55 feet from the side lot lines, which would
provide a setback ratio of 1 foot for every 1 foot of height
of the structure.
During the review of the two permits for private windmills
that were approved in October 2008, staff identified the
height and setbacks of the proposed structures as being the
primary areas for concern. Given the interest in the
application of these systems for private use and
anticipating their more frequent application as a viable
alternative energy source for citizens, staff has determined
that a more comprehensive set of Ordinance provisions is
warranted at this time to address wind energy systems that
provide power for on-site users.
Staff would note that commercial Wind Energy Systems (i.e.,
systems installed for the purpose of generating power for
sale) are currently being regulated under existing Zoning
Ordinance provisions for public utilities (Category 20) and
require special exception approval. This text amendment
makes no changes to these larger-scale types of facilities.
Proposed Amendment
The proposed text amendment would specifically establish
on-site Wind Energy Systems as a permitted accessory use in
Section 6-102.32, with specific limitations as further set
forth in the proposed text. The provisions establish lot
size, setback, design, and maintenance standards related to
such systems, as well as approval procedures. For
additional background information, staff is providing two
detailed documents providing additional technical
information as well as a review of local ordinances with
this staff report: A Guide for State and Local
Governments prepared by the American Wind Association
and published in September 2008 (Attachment 2) and Local
Ordinances to Regulate Wind Energy Projects prepared by
John D. Hutchinson V of the Jennings Gap Partnership for the
Shenandoah Valley Network and Rockingham Community Alliance
in February 2009 (Attachment 3).
Definition
The text
amendment is intended to address wind energy systems that
are utilized for the generation of utility power for private
consumption, as opposed to generation of utility power for
commercial sale. The proposed definition makes it clear that
the systems are for on-site consumption while still
maintaining flexibility for net metering, or the selling of
excess power back to a utility company:
Wind Energy
System: A wind energy conversion system consisting of a
wind turbine, a tower and associated control or conversion
electronics. A system is considered an On-Site Wind
Energy System only if it supplies electrical power
solely for on-site use, except that when a parcel on which
the system is installed also receives electrical power
supplied by a utility company, excess electrical power
generated and not presently needed for on-site use may be
used by the utility company (i.e., net metering).
Permitted Zoning Districts
The proposed amendment limits on-site wind energy systems to
the RA/Rural Agricultural and RC/Rural Conservation
Districts.
Lot Size and Setbacks
Staff originally drafted amendment language that limited
wind energy systems to rurally zoned parcels containing a
minimum of five acres. The intent was to discourage the use
of such systems on smaller parcels where they may have
increased impact on neighboring properties. However, after
some discussion with the Planning Commission, there was
consensus that a setback requirement provided better
protection than a lot size requirement, as the location of
the facility on the lot would determine its impact on
adjoining properties. Therefore, the 5-acre minimum lot
requirement was eliminated from the draft regulations.
The proposed setbacks are to be based on the proposed height
of the overall structure. The original setback proposed by
staff was one foot for each foot of height. However, based
on discussion at the work sessions, the Planning Commission
recommended additional setbacks to protect the surrounding
community from potentially negative impacts of the use.
The provisions now contain a setback requirement from the
property line of 110 percent of the height of the structure
plus an additional setback requirement from existing
residential units on adjoining properties of 150 percent of
the height of the structure. A waiver provision has been
included for the 150 percent setback from a residential
unit, based upon written consent and recordation of an
easement from the affected, adjacent property owner. The
waiver provision is based on that utilized in Rockingham
County.
Height
The majority of the local governments with existing
standards for personal Wind Energy Systems do regulate
height in some manner. Specific examples include:
|
Jurisdiction |
Height Limit |
|
Clarke County |
Allowed by-right up to 100 feet, maximum 2 units.
More units with special permit. |
|
Halifax County |
No height limit specified, but none allowed without
special permit. |
|
Highland County |
Height limit of the Zoning District, greater height
allowed with special permit. |
|
Pulaski County |
60 feet, with special permit (~70-80’ with turbine). |
|
Rockingham County |
65 feet on lots 1-5 acres, with special permit
(~75-85’ w/turbine) and up to 80 feet on lots >5
acres, with special permit (~90-100’ w/turbine). |
|
Rockbridge County |
No height limit specified, but none allowed without
special permit. |
|
City of Suffolk |
120 feet for a small system (output of 25kW or less)
by-right and 250 feet for a large system (output of
26kW up to 999 kW) with a conditional use permit. |
The review of other jurisdictions shows that regulations
vary significantly, from allowing no systems, regardless of
height, up to as high as 120 feet by-right or 240 feet with
a special permit. The initial text amendment was drafted to
include a maximum height limit of 80 feet, which is
consistent with the by-right height of telecommunication
towers in Article 11 of the Zoning Ordinance. Staff has
further researched the issue of height at the request of the
Planning Commission in order to help clarify the minimum
reasonable height for a standard, 10 kW output, wind energy
system, which typifies those most commonly utilized for
private use.
Generally, a wind energy system that is closer to the ground
will receive more turbulence and will operate inefficiently,
and overall wind speed decreases as you move closer to the
ground. An October 2005 issue of the Windletter,
the monthly newsletter of the American Wind Energy
Association, clearly describes the importance of height to a
wind energy system (see Attachment 4 for the full document):
There are two things that can diminish the wind resource for
a small wind turbine. The first is ground drag. Ground drag
is the friction that occurs between the surface of the earth
and air masses that flow over it. The more cluttered the
landscape (with trees and buildings), the greater the ground
drag will be in a given area. Ground drag reduces the wind’s
speed, reducing its kinetic energy. The reason this is so
important is because the output of a wind turbine is
proportional to the cube of the wind speed. For example,
increasing the wind speed from 10 miles per hour to 12 mile
per hour results in a nearly 73% increase in the kinetic
energy available in the wind.
The second thing that can reduce the output of a wind
turbine is the turbulence caused by the obstacles that
clutter the earth. Trees and buildings cause the wind to
tumble and swirl rather than flow smoothly. Besides reducing
the kinetic energy in the wind by slowing it down, turbulent
winds also put undue stress and strain on the wind turbine
and tower. Turbulence increases the maintenance on a wind
generator, while it effectively reduces its life expectancy.
Turbulence is the proverbial double whammy for small wind
turbines!
A general ‘rule of thumb’ established by the American Wind
Energy Association, and widely used by both local
governments and industry related groups, is that the entire
turbine itself must be a minimum of 30 feet above anything
within 500 feet of the tower or the local tree line,
whichever is greater. Since the turbine itself can be as
large as 10-20 feet in diameter for a small Wind Energy
System, this means the total height of the tower must be 40
feet above obstructions to be effective.
A review of many of the small energy systems available for
purchase suggests that a height of 70-80 feet to the top of
the blade is the typical height, which assumes that the
system is adjacent to a home and tree line no more than 30
feet in height. Typical house height is often slightly
more, and while the height of tree lines varies
substantially from site to site, it is not unusual to find
tree stands more than 30 feet in height.
The issue of height was discussed by the Planning Commission
at length. An 80 foot by-right height limit was proposed in
the original staff draft. An alternative approach discussed
was to allow a somewhat lower height, such as 60 feet
by-right, and more height, up to 100 feet, with a special
permit. This approach would allow most proposals to be
evaluated on a case-by-case basis, taking into consideration
the constraints of the particular property, including
potential impacts. A negative impact of the special use
process is that it would add costs to prospective users, but
the current $500 application fee for special permits is
relatively minor compared to the typical $10,000 to $20,000
cost for these systems. In addition, it introduces a
public hearing process into the review and approval of such
systems, which may be controversial.
Ultimately, the Planning Commission recommended draft
language allows 80 feet by-right and up to 100 feet with a
special permit.
Visual Impacts
While the issue of visibility is based primarily on the
height of a wind energy system, several other factors do
contribute to its visual impact. As originally drafted,
staff has included several other provisions aimed at
reducing the visible obtrusiveness of Wind Energy Systems.
Tower Type
There are three typical types of towers utilized for most
wind energy systems: guyed towers, lattice towers, and
monopoles. According to industry sources, the lattice tower
is the least expensive alternative for most systems, but the
most utilized is the guyed tower, in part because these can
be raised and lowered with a winch for maintenance.
  
Guyed Tower (being raised) Lattice
Tower Monopoleonopoleonopole
Staff is recommending that only guyed and monopole towers be
allowed in cases where the tower is visible from adjoining
property or the public street and/or public places, in order
to reduce visual impact.
Color
A provision regulating the color of wind energy systems is
also provided. A review of industry information indicates
that most systems come in a galvanized steel finish or in an
unobtrusive color such as white or gray; this is consistent
with the regulatory practices in other communities. Staff
has also included an alternative that would allow a property
owner, with Zoning Administrator approval, to paint the
system in order to further blend it into the surrounding
environment.
Ridge Lines
Also related to the visibility of wind energy systems is the
concern that a unit could be placed on a visually prominent
steep slope. This is of particular concern since ridgelines
typically would provide the best location for wind
generation. For this reason, the Commission recommended at
its last work session that a ridgeline prohibition be
drafted and staff has included this in the draft provisions.
Signage and Lighting
Additional standards are included that prohibit signage and
lighting on wind energy systems.
Removal if Abandoned
With respect to the concern regarding the existence of
abandoned systems, a provision has been included that will
require the removal of any wind energy system that has been
abandoned and/or is inoperable for a period of more than
twelve (12) months.
Process
The Planning Commission initiated this proposal at the
regularly scheduled meeting held on December 10, 2008. Work
sessions and public hearings were held on January 29, 2009,
February 26, 2009, and March 26, 2009, with the Planning
Commission voting 4-1 in March to recommend approval of the
amendment to the Board of Supervisors, with Ms. McCarty
voting against because of concerns about height.
|