Report for: FuturEnergy · FuturEnergy - 1kW Airforce Wind Turbine Noise Assessment Status: Final 1 6 . 0 7 . 2 0 1 5 P a g e | 3 E m a i l : e n q u i r y @ a c c o n -u k . c om

Report for:

FuturEnergy

1kW Airforce Wind Turbine

Noise Assessment

Status: Final Date: 28.08.2015

FuturEnergy - 1kW Airforce Wind Turbine Noise Assessment Status: Final

1 6 . 0 7 . 2 0 1 5 P a g e | 2

E m a i l : e n q u i r y @ a c c o n - u k . c o m ● w w w . a c c o n - u k . c o m U n i t B , F r o n d s P a r k , F r o u d s L a n e , A l d e r m a s t o n , R e a d i n g , R G 7 4 L H

R e a d i n g O f f i c e T e l : 0 1 1 8 9 7 1 0 0 0 0 F a x : 0 1 1 8 9 7 1 2 2 7 2

B r i g h t o n O f f i c e T e l : 0 1 2 7 3 5 7 3 8 1 4

FuturEnergy - 1kW Airforce Wind Turbine

Noise Assessment

Author: Mike Ledbetter

Contributors: David Yates

Approved By:

Graham Parry

Managing Director

Report For: Sandra Shirley

FuturEnergy Limited

Ettington Park Business Centre

Stratford-upon-Avon

Warwickshire

CV37 8BT

Date: 28.08.2015

Version Number: A2529/N/001

Status: Final

This report has been prepared by ACCON UK Limited with all reasonable care and diligence within the

terms of the contract with the client. We disclaim any responsibility to the client and others in respect of

any matters outside the scope of the above. We accept no responsibility to third parties to whom this

report, or any part, thereof is made available. Any such party relies upon the report at their own risk.

mailto:[email protected]

http://www.accon-uk.com/


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Table of Contents 1. INTRODUCTION ................................................................................................................. 4

2. LEGISLATION, POLICY AND GUIDANCE .......................................................................... 5

2.1. British Standard 61400 part 11 ................................................................................ 5

3. MEASUREMENT SURVEY ................................................................................................. 6

4. NOISE ASSESSMENT ........................................................................................................ 8

List of Appendices Appendix 1 Glossary of Terms ........................................................................................................ 9

Appendix 2 Specification of the Airforce 1 Wind turbine ................................................................ 11

Appendix 3 Baseline Noise Monitoring Location ........................................................................... 14

List of Tables Table 4.1: Sound Power Levels at Specific Wind Speeds ............................................................... 8




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1. INTRODUCTION

ACCON UK Limited (ACCON) have been commissioned by FuturEnergy to carry out a noise

measurement study for the 1kW ‘Airforce’ type wind turbine installed at Pebworth. This

assessment has been carried out broadly in line with the method identified in BS 61400 part

11.

The purpose of the noise measurement study was to provide appropriate noise data for the

wind turbine across a range of wind speeds.

An acoustic glossary is provided in Appendix 1. A specification of the wind turbine is

provided in Appendix 2.




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2. LEGISLATION, POLICY AND GUIDANCE

2.1. British Standard 61400 part 11

BS 61400 part 11:2013 ‘Wind Turbines: Acoustic Noise Measurement Techniques’ sets out a methodology for measuring and characterising noise emissions from wind turbine generator systems.

The procedures within the standard are ’intended to facilitate characterisation of wind turbine noise with respect to a range of wind speeds and directions. Standardisation of measurement

procedures will also facilitate comparisons between different wind turbines.

The procedures present methodologies that will enable the noise emissions of a single wind

turbine to be characterised in a consistent and accurate manner. These procedures include

the following:

• Location of acoustic measurement positions;

• Requirements for the acquisition of acoustic, meteorological, and associated wind turbine operational data;

• Analysis of the data obtained and the content for the data report; and

• Definition of specific acoustic emission parameters, and associated descriptors which are used for making environmental assessments.’

ACCON have utilised an assessment methodology broadly in line with the methodology, for

small wind turbines, that is detailed in Annex F.




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3. MEASUREMENT SURVEY

In order to determine the sound power level of the 1kW ‘Airforce 1’ type wind turbine at

different wind speeds, noise measurements were carried out between 1200 hrs on 30th June

2015 and 1200 hrs 31st July 2015. The assessment was carried out at a site in Pebworth

where a trial wind turbine has been installed. Simultaneous wind and rain data was collected.

The surrounding area has relatively flat topography and consists of arable and pasturable

land. The nearest buildings were at such a distance that no acoustic effect on the noise

measurements would be observed. The nearby roads are low density and therefore would

not affect the noise measurements significantly.

The noise measurements utilised a Rion NL-52 in a free-field location approximately 5m from

the wind turbine tower. The sound level meter is a Type 1 instrument and has a current

certificate of calibration. Before and after the measurement period, field calibration was

carried out in order to ensure that the equipment had remained within reasonable calibration

limits (+/- 0.5 dB).

Figure 3.1 identifies the noise levels and the wind speeds recorded over the measurement

period. Figure 3.1 also identifies where periods of rain were experienced and these periods

of data have been removed from any further analysis.

The noise monitoring position is shown on a site layout plan in Appendix 3.




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Figure 3.1: Noise Levels for the Entire Measurement Period

0

10

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30

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/06

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:27

Noise Levels 30.06.2015 - 31.07.2015

Windspeed (m/s) Noise Level (dBA) Rain




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4. NOISE ASSESSMENT

The noise levels and wind speeds, as shown in Figure 3.1, have been assessed in line with BS

64100 part 11. The apparent sound power level at the centre of the turbine for specific wind speeds

is shown below in Table 4.1.

Table 4.1: Sound Power Levels at Specific Wind Speeds

Wind Speed

(m/s) 1 2 3 4 5 6 7 8 9 10 11 12

Apparent Sound

power Level

(Lwa)

66.0 67.9 68.7 69.7 70.9 72.1 72.7 73.0 73.5 74.6 76.6 77.8

From the sound power levels identified in Table 4.1, a noise label has been produced including an

immission noise map of the Airforce 1 wind turbine. This can be seen in Figure 4.1.

Figure 4.1: MCS Noise Label

Acoustic Noise Levels

Turbine Make: FuturEnergy Model: Airforce

Noise Emission Level Noise Penalty

Sound Power

Lwd, 8m/s 73.1

Noise Slope,

SdB

(dB/m/s)

1 NO

0.0

2.0

4.0

6.0

8.0

10.0

12.0

8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44

Win

d S

pe

ed

(m

/s)

Distance from Rotor Centre (m)

Immission Noise Map

( Not including Noise Penalty)

50-55

45-50

40-45

35-40

30-35

25-30




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Appendix 1

Glossary of Terms




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Appendix 1: Glossary of Terms

Term Description

‘A’-Weighting This is the main way of adjusting measured sound pressure levels to take into account human hearing, and our uneven frequency response.

Decibel (dB)

This is a tenth (deci) of a bel. Decibel can be a measure of the

magnitude of sound, changes in sound level and a measure of

sound insulation. Decibels are not an absolute unit of measurement

but are an expression of ratio between two quantities expressed in

logarithmic form.

LAeq,T

The equivalent steady sound level in dB containing the same

acoustic energy as the actual fluctuating sound level over the given

period, T. T may be as short as 1 second when used to describe a

single event, or as long as 24 hours when used to describe the

noise climate at a specified location. LAeq,T can be measured directly

with an integrating sound level meter.

LA10

The ‘A’-weighted sound pressure level of the residual noise in

decibels exceeded for 10 per cent of a given time and is the LA10T.

The LA10 is used to describe the levels of road traffic noise at a

particular location.

LA50 The ‘A’-weighted sound pressure level of the residual noise in

decibels exceeded for 50 per cent of a given time and is the LA50T.

LA90

The ‘A’-weighted sound pressure level of the residual noise in decibels

exceeded for 90 per cent of a given time and is the LA90T. The LA90 is used to

describe the background noise levels at a particular location.

LAmax The ‘A’-weighted maximum sound pressure level measured over a

measurement period.




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Appendix 2

Specification of the Airforce 1 Wind turbine




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APPENDIX 2 – Specification of the ‘Airforce 1’ 1kW wind turbine

Manufacturer FuturEnergy

Model Number Airforce 1 kW

Serial Number 6026

Axis Plane Horizontal

Up/Downwind Rotor Upwind

Hub Height 8m

Distance from rotor

centre to tower axis

33cm

Rotor Diameter 1.8m

Tower type Tube

Turbine control Passive stall

Constant or Variable

Speed

Variable

Rated Power output 1kW

Control Software

version

0

Number of Blades 3




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Power Specification and Power Curve




1 6 . 0 7 . 2 0 1 5 P a g e | 1 4




Appendix 3

Baseline Noise Monitoring Location




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LEGEND

Client: FuturEnergy

Description: Baseline Noise Monitoring

Design ML 20/08/2015

Drawn ML 20/08/2015

Rev: A Description:

FINAL FuturEnergy Checked DY 20/08/2015

Appendix Three

Scale Not to Scale

Noise Monitoring Position

Wind Turbine Location



E m a i l : e n q u i r y @ a c c o n - u k . c o m

R e a d i n g O f f i c e :

T e l : 0 1 1 8 9 7 1 0 0 0 0 F a x : 0 1 1 8 9 7 1 2 2 7 2 U n i t B , F r o n d s P a r k ,

F r o u d s L a n e , A l d e r m a s t o n , R e a d i n g , R G 7 4 L H

B r i g h t o n O f f i c e :

T e l : 0 1 2 7 3 5 7 3 8 1 4 C i t i b a s e , 9 5 D i t c h l i n g R o a d ,

B r i g h t o n , E a s t S u s s e x , B N 1 4 S T

www.accon-uk.com



Documents

Report for: FuturEnergy · FuturEnergy - 1kW Airforce Wind Turbine Noise Assessment Status: Final 1 6 . 0 7 . 2 0 1 5 P a g e | 3 E m a i l : e n q u i r y @ a c c o n -u k . c om