Small Wind Turbines are NOTLarge Wind Turbines!

They make less noise than Large Wind Turbines.

They do not make the same low frequency and infrasound as Large Turbines .

They are on shorter towers and have a smaller diameter.

The sound does not travel as far as large wind turbine.

They will be located closer to the neighboring residence. Low Visual Impact.

Vermont Definition of small wind : Less than 100kW.

VESTAS V117 3.3MW Rotor Diameter 117m (384ft.) Swept Area 10,751 sq. meters Tower Height 450 ft. Tip Speed 243 mphRotation Speed 17 RPM Noise Max. 107dBA Lwa

Small Wind Turbine:

Bergey Excel 10 Rotor Diameter 7m (23 ft. Swept Area 38sq. meters Tower Height 100 ft. Noise Max. 96 Lwa Low Frequency Noise NoneLess visual impact

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29Bergey 0 0 0 0 0 0 0.2 0.4 0.6 0.8 1 1.2 1.5 1.9 2.3 3 3.5 4 4.6 5.2 5.8 6.7 7.7 8.8 9.5 10 10 10 10Weibull 5m/s 0 0.5 1.5 3 5 7 9 10 10.5 11 11 10 7.5 5 3.5 2 1 0.6 0.5 0.4 0.3 0.25 0.1 0.1 0.1 0.1 0.1 0.1 0.1

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Turbine Comparison Vs Wiebull Curve

WIND SPEED MPH

Pow

er K

W

perc

enta

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f tim

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Bergey Excel 10kW

55 dBA________________________

__________ 49dBA

_______________________________ 47 dBA

____________________________________________43 dBA

12%_____________________ Wielbull Probability of Incidence5m/s (11.2 MPH) average

10%_______________________

7%_________________________

5%_________________________

2%_______________________

1%________________________

The Bergey Excel 10 wind turbine makes its max. noise at 26 mph, which happens less than 0.2% of the time, or 16 hours out of 8760 hours per year.

Sound Comparison Vs Weibull Curve

Per IEC 61400-2 small wind turbine certification per AWEA 9.1 (SWCC)

Peak Lwa Sound Max Distance ACRES

Power dBA dBA at 200ft. At 35 dBA Required

Bergey/ Excel 10 8.9kW 96 dBA 55 dBA 1300 ft. 155

Bergey/ Excel 6 5.5kW 100 dBA 59 dBA 1600 ft. 235

Kingspan /KW6 5.2kW 100 59 dBA 1700 ft. 265

Leley Aircon/ LA10 9.6kW 94 dBA 54dBA 1000ft. 100

Leley Aircon/ LA30 27.2kW 99 dBA 58 dBA 1500ft. 206

Pika /T701 1.5kW 94 dBA 54 dBA 1000 ft. 100

Xzeres/442SR 10.4kW 96 dBA 57 dBA 1300 ft. 155

Xzeres/ Skystream 2.1kW 102 dBA 59 dBA 1600 ft. 235

Ghre Power FD-2150 61.2kW 98 dBA 55 dBA 1300 ft. 155

Small Wind turbine customers ask……………..

How many acres do I need to install a wind turbine?

5 Acres?

10 Acres?

2600 ft. 2600 ft. 2600 ft. 2600 ft.

1300 ft.

1300 ft. 1300 ft.

1300 ft.

155 Acres

Bergey Excel 1055 dBA @ 200 ft.1300 ft. setback155 Acres

35 dBA max.

A 14 Acre Property can meet the sound ordinance but be denied a CPG permit because of the setback rule of 2 x timesthe top of the blade.

Noise analysis per WindPRO softwareBergey Excel 1057dBA @ 200 ft. 1300 ft. = 35 dBAPer IS0-9316-2

Wind Turbine Height 125 ft.Setback 250 ft.Property Width 310 ft.Property 14 AcresSound Setback

35 dBA 1300 ft.42 dBA 650 ft. 45 dBA 430 ft.

An example of a property that isdenied a CPG. The Sound Ordinance is met but the setback rule isexceeded.

Low Wind = Low Background Noise

High Wind

TWO SOUND & WIND ENVIRONMENTS

Terrain Blocking

THINGS TO CONSIDER:

1. Small wind turbines make their maximum noise level when the wind is high, above 15-25 mph. A that time, a neighbor will most likely go inside and shut his/her windows at night.

2. Neighbors will most likely shut the windows at night and be inside during the winter months as well.

3. A house can attenuate the sound down 6-25 dBA ( 15 dBA average) from the outside to the inside. (1,2,3)

4. Small wind turbines do not have the same low frequency sound and infrasound that large wind turbines have.

5. Small wind turbines do not have the capability to perform “Noise Reduction Operation” (NRO) because they have fixed blades that do not articulate or change pitch. Therefore, they would have to meet the lowest night time specification of 35 dBA.

1. World Health Organization: http://www.euro.who.int/__data/assets/pdf_file/0017/43316/E92845.pdf (pg. 11) 2. Feb. 25, 2014 Prepared by Les Blomberg, Noise Pollution Clearinghouse3. Wednesday, November 9, 2016 , report prepared by Acentech for the Department of Public Service

6. Small wind turbines are certified to IEC-61400-2/ AWEA 9.1, not IEC 61400-11. Small wind turbines are measured in dBA and do not require octave-band or frequency measurements in order to be certified. (1)

7. In an area of 11 mph average wind, maximum noise will happen less than 0.2 % of the time, which is less than 16 hoursper year. (out of 8760 hours per year. )

8. Trees can make 45-55 dBA of background noise at 15-25 MPH during the summer. 35- 45dBA in the winter.

9. The automatic setback limit should be reviewed with the CPG application. Many small properties would pass the sound ordinance but be eliminated by the setback rule.

1. SWCC Small Wind Certification Council www.smallwindcertification.org

Scenario to consider:

A Bergey Excel 10 small wind turbine (10kW) is installed 650 ft. from a neighbor’s house and makes 42 dBA of noise occasionally at high wind 16 hours out of 8760 hrs. per year. At night, the neighbor has gone inside and has closed the window because of the high wind or because it is winter time. The house provides 15 dBA of sound attenuation average. The net sound would be less than 30 dBA inside the house. Also take into account that any trees outside the house could provide 35-45 dBA of background noise in the winter, and 45-55dBA in the summer, that would mask the sound of the turbine as well.

Conclusion:

Recommended changes to Rule 5.700:

1. Specification: should be 42 dBA max. (night and day) for small wind turbines under 100 kW. Small wind turbines should be required to provide data in dBA, and they should not be required to provide Octave-band frequency data per IEC-61400-11. The sound measurement should be per IEC-61400-2/AWEA 9.1 (Small Wind Turbine Certification), not IEC 61400-11 ( Large Wind Turbine Certification).

2. There should be minimal setback limit in Rule 5.100 or 5.700 ( 1.1 x top of blade). If the small wind turbine meets the sound ordinance, then the setback should be determined in the CPG application process and the visual aesthetics of the project should be judged on a case by case basis.