Wind turbine zoning at a small scale presents a dilemma to any municipality seeking to promote green development and sustainability. With sustainable energy a hot topic, with the LEED® standards from the U.S. Green Building Council awarding points for green energy, and with individual homeowners trying to lessen dependence on big utilities, this subject will pop up in cities, suburbs, and towns.
First we will discuss the issue of a single wind turbine, providing energy mostly to the property owner, although more than half the states allow "net metering" in which an individual may sell excess electricity generated back to the power grid.
Most municipalities simply would not know how to deal with such a request, so start thinking about how to revise your zoning regulations to deal with an immediate or future possibility. Of course, many towns may not have any locations suitable for wind energy generation, so this will be a moot point for them.
If you already have a tower zoning, cell phone zoning, or antenna zoning provision, refer to those for ideas on how you want to regulate this new form of tall, slender object.
Usually it is helpful to divide wind turbines into small and large, based on their energy output. But even "small" may seem like a problem to planning commissioners who aren't ready for a 60-foot tall spinning object in back yards.
Usually the ordinance will define a structure in such a manner that a single turbine would have to be reviewed under zoning, but height restrictions and limits on the number of accessory uses (examples are garages and sheds) would stop the proposal in its tracks in most locations.
Until the technology is more widely understood by the public and elected officials, we recommend that wind turbine zoning be restricted to instances in which a conditional use permit is granted. A conditional use permit usually requires exactly the same process as rezoning. In other words, public hearings before the planning commission and city council are to be expected. A few cities and counties may simplify the conditional use process. Under such a permit, the governing body can require "conditions" for construction or performance on an ongoing basis. Often the ordinance allows a city or county council fairly wide discretion on what these conditions will be.
Thus far people seem pretty much united in the notion that we don't want a single-family residence in a subdivision erecting a tall wind turbine. But a single house on forty acres, with no close neighbors, might be a different story.
However, be aware that there are small rooftop units that generate only a tiny amount of electricity; the proponent might be able to make a pretty good argument for that type.
There are many
types of wind turbines coming into production, and a Minnesota model
ordinance in 2005 divided them into commercial and non-commercial
scales. You may want to do the same. Just be aware that outputs,
height, and thickness do vary. Mostly on this page we address the windmill in close proximity to residences, but commercial scale installations on farmland are becoming quite common. If those areas are zoned, you will need to consider carefully how and whether to accommodate hundreds of windmills in agricultural zoning.
So the question becomes how much land is enough to prevent a wind turbine from having a negative impact on the neighborhood? The National Academy of Science has recommended a 2600 foot setback, about half a mile, from the nearest home. Other recommendations and ordinances have allowed much less.
You should have a professional engineer specify the "fall zone" for where the turbine could conceivably land if it were to topple. Certainly your setback from both property lines and buildings that may lie on the same property should exceed that fall zone.
We are early in the process of determining what is appropriate and whether there is any real reason for people to be concerned. Also the technology is advancing, so design changes in the products available might make a real difference in their performance characteristics.
Another issue is noise, an actual complaint when wind turbines have been installed somewhat near residential neighborhoods. However, this problem seems easily addressed. The wind turbine zoning amendment simply should refer to the acceptable decibel level (a measure of noise) in residential neighborhoods, providing one has been established either through zoning or in a separate ordinance.
If not, the highest level of total noise on a regular basis you should tolerate at the outside wall of any house is probably 40 decibels, abbreviated dB. (The higher the decibel number, the louder the noise.)
Our recommendation is to provide through wind turbine zoning that the ambient (existing normal) noise level at the property line could not be increased by any more than 10 dB through addition of the turbine. If you face opposition, of course permitting no increase is a viable option.
Height is certainly an appropriate concern, and related to height is appearance and community design. While almost all residential zoning districts specify a height restriction, wind turbine zoning will need to be realistic about the products and technology available. Current wind turbines need to be at least 20 feet above the trees to be effective.
A minimum clearance from the ground to the lowest turbine also must be established. At least 12 feet is recommended. Other setbacks, such as from roads, rivers, streams, wetlands, conservation areas, or scenic or historic sites may need to be established.
The fact that the stem of the wind turbine designs now most prevalent is slender means that the mass of a single turbine will not appear to be great. The most common design also is white or near-white, with the effect of a graceful appearance to most people. Some will find them ugly because they are unfamiliar. In fact, however, the design is simple and pleasant enough near newer suburban neighborhoods.
The appearance debate seems much more viable when the proposed wind turbine zoning is adjacent to a vintage neighborhood or historic district. The wind industry will have to be resourceful to design a complement to a richly textured neighborhood.
Commercial wind farm zoning also presents the same issues--noise, appearance, height, and proximity to residences. I personally find a large wind farm in a rural or industrial area not at all offensive in appearance, but it will be a matter of lively local debate. We recommend that in a county or town with an agricultural zoning district, wind turbine zoning be allowed with a conditional use permit.
In industrial or commercial zoning districts, you certainly need to require the conditional use permit so that you can control individual site conditions. Generally, we like the potential of applying a wind farm zoning overlay in areas of your city that are appropriate. This can provide that some debate occurs before an actual case arises--always good policy in zoning matters.
A few other requirements apply. Require that feeder power lines from the turbines be buried underground, as those would be some high and ugly wires. Also require compliance with FAA regulations, which may include a small light. You probably will need to permit any type of safety warning signs suggested by the manufacturer.
We want to add two last things. You will hear from bird lovers that wind turbine zoning would cause terrible collisions for our feathered friends. Although there are many other more significant hazards for birds, it would be wise to avoid known nesting and migration areas.
But also the word is around that wind turbines might interfere with cell phone reception, and we're mighty cranky when that happens. Investigate that closely; it seems to be approaching urban myth status.
The trade association for the wind industry is the American Wind Energy Association, which can be expected to provide up-to-date information on the technology.
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