Changing VT State Wind Turbine Noise Regulations › sites › psbnew › files... · Changing VT...
Transcript of Changing VT State Wind Turbine Noise Regulations › sites › psbnew › files... · Changing VT...
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
er K
W
perc
enta
ge o
f tim
e
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