Noise Assessment: minimization of wind farm production losses

Alberto Secades Barreñada

Corporate Technical Support – Performance Engineering

EDPR: global overview

EDPR portfolio totals 8.6 GW

Poland

RomaniaItaly

Portugal

France

Spain

BelgiumUK

#1 #3

#1

#3

1,108 MW 2,368 MW

334 MW

71 MWOffshore under development

374 MW

521 MW

70 MW

Notes: 9M 2014 Figures; Includes 840 MW of Equity Consolidated MW: 487 MW in Portugal (ENEOP), 174 MW in Spain and 179 MW in US

US

Brazil

Canada

#3

30 MW

3,655 MW

84 MW

180 MW under development

Part I: minimization of wind farm production losses

1 Importance of noise assessment in WPO - from Project Management to O&M

1.1 Assessment of Technical Risk

1.2 Noise assessment from Project Management to O&M

1.3 Case study: minimization of production losses due to noise curtailments

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1.1 Assessment of Technical Risk

Risk Mitigation

Production technology

Design must ensure thatassumptions set out for thelife of the project arefulfilled

Life Cycle

Threats

Impact

FrequencyRisk Map

Alternatives

Contingency Plan

Operating Expenditure willbe reasonably forecastedthroughout the whole lifeof the project and willassess factors that caninfluence it

OpEx

Estimated production (NEH)and any factors that mightaffect it (WTG breakdowns,power losses, availability ofspare parts, etc.) must bechecked

Production Availability

NO

ISE

RIS

K

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What ?

• Due to internal restructuring of Environmental activities, CTD decided to centralize the management of noise studies and measurements.

Why ?

• In order to unify practices among all EDPR geographies

• Increase level of technical risk management

• Use of best practices and internal know-how dissemination.

• Optimization of countermeasures from a global point of view

How ?

• Assuring technical quality and scope in the studies/measurements for all EDPR geographies Issuing a Technical Specification that covers the minimum content and requirements.

• Establishing control and decision points in the process.

1.1 Assessment of Technical Risk

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Part I: minimization of wind farm production losses

1 Importance of noise assessment in WPO - from Project Management to O&M

1.1 Assessment of technical risk

1.2 Noise assessment from Project Management to O&M

1.3 Case study: minimization of production losses due to noise curtailments

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1.2 From Project Management to O&M

TypeWind farm acoustic

simulation

Preoperationalsite measurement

(Background)

Noise measurement

during construction

Noise measurement during operation

Noise measurement & simulation

Phase Development Development Construction Operational Operational

Scope

Detect possible noiserestrictions for wind farm layout and WTG

model (EIA report)

Measure the level of sound at wind

farm site previous to starting any

activity(if required)

Measure the level of sound at wind farm site during

construction

Measure the level of sound at wind farm site

during operation

Check for a new noise constraint that

appears during operational phase or

noise guarantee verification

Keyinteractions with WTG

manufacturer

• Define noise guarantee in the TSA

• Check possible limitations regarding:- Low Noise Modes

-Noise Reduction System (SCADA)

•Check noise guarantee in the TSA if necessary• Check correct behaviour of Noise Reduction

System • If required analyze the need for exceptional

features: tailor-made Low Noise Modes, installation of passive devices, etc …

2 Different types of services

Studies & measurements provide information related with the Environmental Impact Assessment of the wind farm project

Studies & measurements detect potential noise restrictions and curtailment of active power

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Part I: minimization of wind farm production losses

1 Importance of noise assessment in WPO - from Project Management to O&M

1.1 Assessment of technical risk

1.2 Noise assessment from Project Management to O&M

1.3 WF case study: optimized production losses due to noise curtailments

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1.3 Example - wind farm case study

On - site support

Data Verification

Software FeedbackChecking

results

• Collecting and sending data from SCADA to acoustic consultant • Data synchronization• Comparing different sources of data

• Study of the current applicable regulations • Checking noise values sent by acoustic company in order to optimize the study • Different G coefficient – season year ( 0.2 / 0.5 / 0.9 ) and Aatm

• Detailed contribution of each WTG

• Focused on correct synchronization of SCADA data VS measured noise samples• Exchanging information with the acoustic consultant to discuss the best way to proceed• Objective = minimization of production losses

• Checking the values obtained• Comparing with our own estimations (internal simulation)• Introducing modifications in the report

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No restrictions

Initial Noise Reduction Strategy

No wind direction sectored Sectored by wind direction

Optimized Noise Reduction Strategy

-45 % of power production during night period +17 % of total power production in the wind farm

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1.3 Example - wind farm case study

Part II: minimization of wind farm production losses

2 ISO 9613-1/2 propagation model gaps and noise simulation

2.1 ISO 9613-2 & wind turbine noise

2.2 EDPR noise assessment software

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2.1 ISO 9613-2 & wind turbine noise

• ISO 9613-2: 17 year-old empirical scheme • Noise sources up to 30 meters height (low height compared to modern wind turbines)• Non-wind-dependent and stationary noise sources (opposite to the concept of wind turbine)• Considers only an undefined account of wind shear effect regarding noise propagation.• Conceived measurements under downwind conditions: wind speed up to 5 m/s (@10 m height).

• Wind turbines: wind-induced generation• Trailing-edge noise associated with blade tip: modern turbine blade-tip noise source > 100 m. height.• Noise assessments for wind farms : wind speed up to 10 m/s (@10 m height)• Wind shear importance in noise assessment of wind farms: necessary to address the potential for complaints under worst-case wind shear conditions. Also study propagation phenomena such as AM modulation may become an issue in certain countries (UK)

ASSUMPTIONS

REALITY

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Consequences of poor noise assessment/simulation (WPO perspective)

An inaccurate noise simulation has the following consequences in the project:

• Overestimation: production loss overestimation (NEH). WTGs can be removed from original layout without technical justification. Project can be unnecessarily “killed”.

• Underestimation: production loss underestimation (NEH). Active power curtailments due to noise restrictions not expected. Potential good project turns into an unprofitable operational wind farm.

• WTG model: typically different WTG models are compared in order to check the best production available for the same layout noise curtailments have a critical impact on WTG selection process.

• Developers tend to assume all propagation effects are considered by ISO 9613-2 prediction methodology, as it is the standard widely accepted within the wind industry.

Currently different “improved” prediction models are being used but no standard: Nord2000 or ISO 9613-2 with CONCAWE / HARMONOISE corrections ?

2.1 ISO 9613-2 & wind turbine noise

Part II: minimization of wind farm production losses

2 ISO 9613-1/2 propagation model gaps and noise simulation

2.1 ISO 9613-2 & wind turbine noise

2.2 EDPR noise assessment tool

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2.2 EDPR noise assessment tool

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Data required:• WTG acoustic data (octave-band option)• WTGs & receptors coordinates• Background noise (if required)

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Detailed noise contribution of each WTGin one of the receiving points

Useful for a first approach when differentlayouts and WTG models are being studied by Project Management team.

Faster analysis without external consultant

Conservative output results due to ISO 9613 limitations. Consider wind turbine directivity to optimize?

2.2 EDPR noise assessment tool

Part III: minimization of wind farm production losses

3 Infrasound and low-frequency noise – R&D case study

3.1 Introduction & methodology

3.2 Conclusions & next steps

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3.1 Infrasound R&D

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Equipment Sound level meter

Model SVANTEK / SVAN 959

Microphone type GRAS 40AZ / 111298

Preamplifier type SV 12L / 25414

Equipment Acoustic calibrator

Model SONOPAN / KA-50

Microphone + preamplifier located on measuring platform according to IEC 61400-11 standard. Measurements performed without frequency correction (un-weighted SPL, dB)

3.1 Infrasound R&D

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Part III: minimization of wind farm production losses

3 Infrasound and low-frequency noise – R&D case study

3.1 Introduction & methodology

3.2 Conclusions

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• Sound Pressure Level measured at a wind farm in the low frequency range clearly increaseswith wind speed. But this phenomenon cannot be explained only by the increase in noiseemitted by the wind turbines.

• Difference between G-weighted SPL measured with wind turbines ON/OFF < 8dB when measured at 300 meters from closest turbine (wind speed from 3 to 4 m/s @10m reference). Acoustic impact from wind turbines can be quantified (61 dBG). For higher wind speeds the difference is < 3 dB

• When wind speed increases, wind turbines emit more acoustic energy into the environment which concentrates on higher frequency bands (greater than 315 Hz).

• Sound Pressure Level (dBG) variations based on wind turbine induced noise inside dwellings are neglectable.

• Noise levels in the infrasound range observed within tested dwellings close to the wind farm are much lower than levels measured in other common environments (inside a car or in an office with a ventilation system).

Conclusions of the study

3.2 Infrasound R&D: conclusions

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Thank you for your attentionQ&A

Alberto.Secades@edpr.com