Planning Board
Town of Bethany
Bethany Center Road
East Bethany, NY 14054

Board Members:

I am writing to share some research into the safety concerns of large scale wind turbines. My concern in writing to you is that, should these wind projects be constructed in Bethany, safety and the continuance of our rural lifestyle be a primary concern, and the developer's profits be secondary. I'd also like to ensure that the town and its residents are treated fairly and with respect by the developers. It is my firm belief that this will not happen unless we present the developers with clear zoning ordinances derived from detailed study of the issue.

Re: Property Setbacks

I would like to present some findings I have made on proposed and existing setbacks from other communities and ordinances related to that activity. Very recently, communities have begun implementing three separate categories of setbacks for large-scale wind turbines – a) noise and b) flicker setbacks are traditionally measured in the existing terrain (as objects, elevation and so forth will affect their measurements), while c) physical setbacks are traditionally fixed on a community-wide basis. I have not attempted to address noise or flicker setbacks in this document, only physical setbacks.

A Realistic Danger Assessment

In considering the type and distance for physical setbacks, it is useful to remember that should any damage be caused by turbine operation, non-operation or falling down, a plaintiff could bring the town into a potential lawsuit based on inadequacy of the zoning setbacks. To bring some perspective to the potential for loss of life and property, here are some notes on past and potential accidents of the major types expected:

[High Wind Failure] In Germany in multiple years including 1999, 2000 and 2003, the brakes on wind turbines failed in high wind, causing the rotor to hit the tower at high speed. This resulted in anything from parts of the blade to the entire nacelle (rotors attached) flying off the tower. Blades and other substantial parts have landed as far as 1,650ft away. In one case, a blade pierced a 24cm thick stone wall to rest in a (thankfully) empty factory.

Beginning in 2001, there are numerous counts of residents being evacuated and motorways closed anywhere from several hours to overnight under these same conditions. These turbines were model V80s, which have an 80m (264ft) hub height compared with Bethany's proposed 330ft hub height. The GE model 3.0 turbines proposed in Bethany have the potential to throw debris further.

[Structural Failure] In France, in 2000, a turbine mast broke and toppled over during a storm with no further information available from the wind company. This was the first in a series of such incidents that led to a formal investigation. In Germany, 2000, four turbines experienced sudden and total collapse due to “concrete damage” at the base. Forty-four similar turbines were shut down pending investigation.

In Germany, 2002, a blade broke in mid-turn with an audible “crack.” Pieces were found scattered throughout surrounding fields. The cause was later found to be metal fatigue. The most common reasons for structural failure are improper installation and/or manufacturing defects.

[Fire] In Powys, Wales in 1997 a 4 year old turbine overheated and caught fire inside the nacelle. Witnesses reported “balls of fire” coming from the turbine as burning parts flew out of the nacelle. The turbine's rotors were impossible to stop as the brake controls were aflame. Rotating, burning debris was thrown 150m (495ft), setting the hillside and a public right-of-way on fire. With proportions, Bethany could potentially be facing 620ft of fire debris.[4]

Due to the height and danger of falling debris, the fire brigade could only cordon off the area and wait for the fire to burn out. This is the case with every recorded turbine fire I have been able to locate – no fire brigade (department) has been equipped to actively fight a turbine fire.

[Ice Throws] In Minnesota, 2002, a maintenance worker preparing to ascend the turbine was cut in half by a falling sheet of ice. There are reports too numerous to count of automobile damage due to falling lumps of ice – usually described as about the size of tennis balls.

Damage has occurred as far away as 80m (264ft), including smashed windshields and windows; dented cars and roofs; and accidents on roadways (cars hitting large chunks of ice lying in the road, not ice hitting cars).

[Oil Spills] In Germany, 2003, a turbine destroyed by a storm was found to have been leaking oil into the ground. Three other turbines were found to leak that same year. As these were situated in an area protected for municipal drinking water supply, the turbine company was sued. No information is available on the result.

These incidents are pulled from a fairly complete list of wind turbine accidents from the late 1990s to present, compiled by Caithness Wind Farms in the UK. This list is available on line.[5] It is 17 pages long and includes at least 20 accidents per year since 1999.

Types of Setbacks

My first finding is that zoning ordinances vary widely in which physical (property) setbacks are required or even mentioned. Most (if not all) ordinances include distances from residences and property lines, while others include these plus roadway, right-of-way, livestock barns and pastures, and others listed below. Obviously, not all communities measure the same types of setbacks and some clearly place more value on livestock and outbuildings than others. I have grouped together definitions that appear to be set for the same or similar reasons.

1)Roadways / Right of Ways / Utility Easements / Buildings / Storage Barns: this setback is typically based on the belief that ice throws or high-voltage electrical fields may interfere with traffic or the activities of persons not related to the project; or damage property. A team of German scientists have put together a simplified equation for calculating that risk[1], d = (D + H) * 1.5, meaning add the diameter of the rotors to the hub height (tower height), then multiply that number by one and a half. With the proposed 3.0mW turbines, that means (240' + 330') * 1.5 or 855 feet. Because the German scientists designate this as a rough calculation and recommend further local studies to determine the exact conditions in a given area, some communities are adding a 10% margin of error (which would make our calculation 941 ft.)[8].

This setback is normally not applied to the access roads built by the wind company for the purpose of erecting, maintaining and decommissioning the turbine itself. In reading various town and county ordinances available online, it is not clear whether the setback applies to established public trails or snowmobiling paths (most likely this information is found in the communities' base zoning definitions, which are not included in the turbine document). In only one Minnesota document was I able to find a direct reference that snowmobile and walking trails were specifically included (that was a proposal from a wind turbine company, not a zoning paper). Given that, in New York, snowmobiling paths are created, mapped and maintained with public money, they might be something the town would like to consider including in any right-of-way setbacks.

2)Property Line: this setback is normally not measured in a fixed distance, but rather equates to the full height of the turbine (the hub height or tower height plus the length of a rotor, also called 'tip height'). The reasonings here are many, the most common being that one might be worried about the tower falling over, in which case it makes sense to set it back that distance from neighboring property; or that there is ample precedent for determining setbacks as equal to the height of any construction within most communities' existing ordinances. Turbine companies will tell you that the chances of a turbine falling over is extremely slim, and they are correct. However, there are other good reasons for keeping property line setbacks to the full height of the turbine.

The argument I find most interesting comes from North Dakota. The Town of Spring Valley (near Bismark) has passed regulations based on landowner rights, to whit: the towers must be placed at least twice their height apart (in our case, no two towers could be any closer than 900'). If the Hatfields and McCoys (neighboring landowners) both sign leases, and the wind company first determines the best placement for Hatfield is within 450' of McCoy's property line, that limits McCoy's ability to lease land to the wind company. In addition, if the turbine is located close to a property line, McCoy might, later on, build an obstruction which would affect wind flow and possibly make the turbine ineffective. While the turbines are tall, certain regular sizes and shapes of objects can severely impact wind flow at higher altitudes. Communities using this reasoning allow an exception where adjacent landowners have signed a joint lease (sharing revenues).[7]

Note that several California documents have established a legal precedent prohibiting towns from enacting ordinances larger than the full turbine height.[3] However, NYSERDA's own document “Wind Energy Development: A Guide for Local Authorities in New York”[9] specifies 1.5 times the full height of the turbine.

3)Livestock Barn / Residence / Business: I find it absolutely fascinating the value some communities place on their people and animals. Some communities have setbacks for residences, but none for business or livestock “homes.” Some have two of the three and some have all three. I believe that, in keeping with our image as a rural community, any setback which applies to residences should also be applied to businesses and barns housing livestock of any kind. This represents the most humane treatment.

The actual distance of the setback is all over the place, from the full tower height (hub height plus rotor length) to a fixed 1,000 meters (3,300 ft). Fixed numbers between 1,200' and 1,850' are most common – one should note that in all instances these were ultimately applied to smaller turbines. A town in West Virginia attempted a fixed mile setback with modern, taller turbines, which was challenged in court; a judge ordered it down to ½ mile.

In the USA, this particular setback represents extremely esoteric concerns – goals include: a) reducing noise by insisting on a minimum distance; b) reducing flicker in the same manner; c) preserving real estate values; d) appeasing residents who don't want tall spinning objects too close to their homes; e) preserving quality of life. Clearly, planners are trying to accommodate the wishes of residents to hold on to the aesthetic and esoteric aspects of their community with these larger setbacks.

In Europe, however, setbacks in the range of 1,650ft have come after hard lessons of property damage and near loss of life as noted above. Germany, in particular, suffered hard as it did not – initially – require sufficient setbacks. The European Best Practices document[6] does not set a fixed distance, but suggests a safety assessment including distance to residences and roadways prior to the installation of any turbine facility. This has resulted in average setbacks for European installations of about 600m or 1,980ft.

The NWCC's Permitting of Wind Energy Facilities Handbook – a US document – [2] notes that ideal setbacks measure at least 750-1,000 ft – written in 2002 when typical a turbine was 80 meters in height. Proportionately for our 100 meter turbines, that setback would equate to 937-1,250 ft.

One final note: repowering. This is the term used by the wind industry to refer to the process of replacing older turbines with newer, generally larger, models. This may happen any number of years into the turbine's lifespan, whenever it becomes economically feasible to do so. While this process requires new permits, some communities are finding they need to re-write setbacks at that time, as they had defined them in fixed footage. In their re-writes, they are generally defining setbacks in terms of the height of the turbine, height of the tower, and/or length of the blades. This would seem to be good practice.

I hope that you find this information useful and welcome your comments and criticisms on how I could be of better help. Note also that sources for my data are presented at the end of this letter.

Thank you for your time.

Sincerely,

Loy Ellen Gross

Summary Numbers

Full Height of Proposed Turbines: 450ft
Typical Roadway / Right-of-Way Setback (US): 500 – 900ft
Calculated Ice Throw Distance: 855ft
Typical Property Line Setback: Full height of turbine (450ft)
Typical Residential Setbacks: 1,200ft – 1,850ft
NWCC's Permitting Setbacks, adjusted for height: 1,250ft

Guideline Text

The minimum setback distance between each wind turbine tower and overhead utility lines, roadways, public and utility right-of-ways, and uninhabited structures shall be equal to no less than 1.65 times the sum of the proposed structure height plus the rotor diameter.

The minimum setback distance between each wind turbine tower and all surrounding property lines shall be equal to no less than 1.5 times the sum of the proposed structure height plus the rotor radius. The property line setback requirement may be reduced by the Town Board when it finds that the following circumstances apply: The property line separates two parcels that are both in the Town of Bethany, and the owner of the parcel for which the reduced setback is sought and the owner(s) of the parcel(s) affected by the reduced setback jointly execute and present for recording a development easement satisfactory to the Town in which the reduced setback is consented to, and construction within, and use of, the easement area is appropriately restricted.

The minimum setback distance between each wind turbine tower and dwellings, active places of business, and structures housing live animals shall be equal to no less than 4.5 times the sum of the proposed structure height plus the rotor radius. The property line setback requirement may be reduced by the Town Board when it finds that the following circumstances apply: the owner of the parcel for which the reduced setback is sought executes and presents for recording a development easement satisfactory to the Town in which the reduced setback is consented to, and construction within, and use of, the easement area is appropriately restricted.

The minimum distance between ground level and any part of the rotor blade system shall be 30 feet.

References

1 Michigan State University Extension: Community Development and Natural Resources Studies (German study regarding risk from ice throws) http://web1.msue.msu.edu/cdnr/icethrowseifertb.pdf

2 National Wind Energy Association Siting Guidelines http://www.nationalwind.org/publications/permit/permitting2002.pdf

3 American Wind Energy Association Small Wind Turbine Siting Guidelines (This is a small turbine document; I have seen it applied to larger turbines, but could not find the reference again when I looked) http://www.awea.org/smallwind/documents/permitting.pdf

4 Photos can be seen at http://www.pbase.com/wp/wind_turbine_photos&page=2

5 Caithness Wind Farms Accident Report http://www.caithnesswindfarms.co.uk/Downloads/Accidents%20-%20June%2030%202005.pdf

6 European Best Practices Guidelines for Wind Energy Development http://www.windfarm.fsnet.co.uk/downloads/bgp.pdf

7 Article from the Bismark Tribune Newspaper. Note this article has been moved to the archives and now requires a subscription to the newspaper: http://www.bismarcktribune.com/articles/2005/08/01/news/state/sta01.txt However, a copy of the original article can be found at http://www.livingingenesee.org/?q=zoning-hurts-wind-development

8 Michigan State University Extension: Community Development and Natural Resources Studies (Application of German Study to zoning) http://web1.msue.msu.edu/cdnr/otsegowindicethrow.pdf

9 NYSERDA Wind Energy Development: A Guide for Local Authorities in New York http://text.nyserda.org/programs/pdfs/windenergyguideappD.pdf