Changing VT State Wind Turbine Noise Regulations

1. Existing Standard of 45 dBA too high

2. Proposed 42 dBA day/35 dBA night level(most conservative in New England)

3. Specifies Measurement Criteria

4. SAME FOR LARGE AND SMALL TURBINES

Complex Process Involving Multiple Stakeholders

Worked at MA DEP 2012-20131. Began at a Time When Many Wind Projects

Were Upcoming or Coming On Line in MA

2. Little Existing Expertise Understanding of Wind Turbine Acoustics at DEP –helped examine regulations

Turbine Complaints1. Not all Projects had complaints – majority of

projects well received

2. Most complaints near larger (> 1.5 MW Turbines near the coast) – NO COMPLAINTS FOR < 1.5KW

Small vs. Large Wind Turbine Dose Response Studies

1. Multiple studies of medium-larger turbines (over 500 KW)(Pederson-Waye, et. al.)

2. Larger turbines have complaints about sound for otherreasons (usually visual) – not typically seen for small turbines

3. No dose response studies located for turbines < 100 KW;simply not considered to be important.

Small vs. Large Wind Turbine LocationsSmall turbines are on flatter locations near people (typically

farms), have higher wind noise background

Amplitude ModulationWinter Sound Levels at a Farm in Vermont

35-40 dBA winter; can be over 50 dBA in the summer

Amplitude Modulation1. A consistent problem near LARGER turbines

2. More prevalent at the sidewind – up to 4 dB in peak to peak variation (thumping sound)

3. MUCH lower levels with smaller turbines – 1 dBA or less

Understanding Infrasound1. Anecdotal Evidence That It may be an Issue

2. Cannot usually be detected by the ear –below audible levels-may still be noticeable (RSOWTA)

3. Can Penetrate Walls and Windows-couple to buildings

Turbine On

Turbine Off

RSOWTA INFRASOUND DATA

Small Turbine Infrasound

1. Much lower levels with small turbines-masked by wind

2. Higher frequency levels of small turbine infrasound-more readily blocked by buildings

3. Not aware of any potential reported effects (vertigo, dizziness) from infrasound near small turbines

Small Turbine Windspeeds

1. Typically run at lower wind speeds, being much closer to the ground – 5 m/sec vs. 7-8 m/sec for larger turbines

2. RARELY RUN AT RATED WINDSPEED OF 11-12 M/SEC –TYPICALLY PRODUCE SEVERAL DECIBELS LESS SOUND THAN RATED

3. Significantly lower time near permitted sound levelsthan for larger turbines

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 11 11 11 10 7.5 5 3.5 2 1 0.6 0.5 0.4 0.3 0.3 0.1 0.1 0.1 0.1 0.1 0.1 0.1

0

2

4

6

8

10

12Sound Power Comparison Vs Wiebull Curve

WIND SPEED MPH

Pow

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W

perc

enta

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f tim

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Bergey Excel 10kW

94 dBA ___________

____ ______ 90dBA

_______________________________87 dBA

___________________________________________84 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< 0.2% of the time.

Wind Turbine vs. Other Noise Sources

SMALL TURBINE SOUND ANNOYANCE

1. Not included in the wind turbine annoyance studies

2. Have sound characteristics closer to continuously operating equipment than larger turbines-fans, industrial equipment

3. Corresponding higher actual annoyance level-45, 50 dBAor even higher-MUCH HIGHER THAN 35 dBA PROPOSED LEVEL

TURBINE SETBACK DISTANCES

1. Large Turbines (2.5 MW) would require nearly 4000 foot setbacks to meet new standards of 35 dBA

2. SMALL FARM TURBINES WOULD REQUIRE NEARLY 1500 FOOT SETBACKS TO MEET 35 dBA LIMIT-AN EFFECTIVE BAN ON SMALL WIND TURBINES AT FARMS AND RESIDENCES

3. 42 dBA standard would be met by small farm turbines at about 650 feet distance – still a considerable setback!

CONCLUSIONS1. Proposed noise regulations are VERY conservative for ALL

wind turbines

2. Significantly different conditions indicate that they are NOT appropriate for small wind-background levels, soundproduction, perception, masking, amplitude modulation,infrasound all different-small turbines have much lesseffect for given sound level

1. PROPOSED REGULATIONS WOULD BE AN EFFECTIVE BAN ON SMALL WIND IN VT

4. Better level for small turbines – 42 dBA day and night (still conservative!)

Thank You!Dr. Howard Quin

hquinconsulting@gmail.com