Evaluating the Effectiveness of an Ultrasonic

Acoustic Deterrent in Reducing Bat Fatalities at

Wind Energy Facilities

Research on Bat Detection & Deterrence Technologies

NWCC Webinar

14 March 2018

Bats & Wind Energy Cooperative &

Deterrent Research

• Since 2006, the BWEC has investigated the potential of

ultrasonic acoustic deterrents to reduce bat fatalities at

wind turbines

– 2006–2008: Lab & preliminary field trials

– 2009–2010: Test Deaton deterrent at an operational wind

energy facility (Arnett et al. 2013)

• 2009: 21–51% fewer fatalities

• 2010: 18–62% fewer fatalities

– 2011–2014: Improvements to Deaton deterrent & preliminary

field trials

– 2015–Present: Several studies testing NRG Systems’ deterrent

Project Team for EERE-funded Study

• Bat Conservation International

• Avangrid Renewables

• NRG Systems

• U.S. Geological Survey

• Funding & in-kind support

– Energy Efficiency & Renewable Energy (USDOE)

– Avangrid, USGS, NRG, & BCI

Project Objectives

• Determine best placement & orientation to ensure safety,

compatibility & functionality

• Assess functionality of newly designed UAD

• Evaluate the effectiveness of UAD to reduce bat fatalities

• Compare costs & benefits of UAD to operational

minimization

Phase 1: Functionality Study

Changing the Technology

• Redesigning the UAD

– From Electrostatic to Piezoelectric transducers

– Better weatherproofing

– Narrower frequency range

• Different frequencies

– Remote communication

Deaton DeterrentNRG Systems’ Deterrent

Location of Deaton Deterrents

Location of NRG Systems’ Deterrents

Ground-based Studies

Preliminary Experiment on Wind Turbines

• Functionality test of the deterrents

– Performance, communication, weatherproofing

• Recorded bat activity using thermal video cameras

Decision on Where to Project the Ultrasound

• Based on previous thermal video studies & data

we collected in 2016

Approximation of SPL & Distance

• ‘Range’ is dependent on frequency

• Eastern red bats ~ 41 kHz

• Hoary bats ~ 21 kHz

• Blade length ~43 m

• SPL to deter bats?

– Species-specific?

Phase 2: Comparability Study

Study Design: Location/Site

Blue Creek, OH (Avangrid Renewables)

• Historical data– Intensive monitoring in 2012, 2013, 2015, and 2106

– Information on timing, number of fatalities, species composition that inform a successful study design

• High Visibility– Flat

– Homogenous, agricultural

– Cooperative landowners that allow for clearing

• Site has a low to moderate wind speed – Comparable to other wind energy sites in Midwest

– Accurately reflects other sites where curtailment is financially challenging

Study Design: # Turbines

• Number of turbines

– Compared sample size of turbines under various

experimental designs

– Chose 16 turbines based on study design

• Considerations

– Statistical power

– Landowner cooperation on turbine locations based on

previous studies conducted at Blue Creek

Study Design: Search Effort

• Duration - 112-night study (14 June–3 October)

– Based on previous monitoring data

– Study period captures peak period of time bats at risk

90m

• Plot size - 90 meters

– Relatively large plot size used to

ensure finding most of the bat

carcasses & minimizing any

potential bias

Curtailment: YesDeterrent: No

Curtailment: YesDeterrent: Yes

Curtailment: NoDeterrent: No

Curtailment: NoDeterrent: Yes

16 Turbines Deterrent

No Yes

Curtailment(5.0 m/s)

No 4 4

Yes 4 4

Study Design: Treatments

Randomized Block Design-Rotating Treatments on a nightly basis-Each turbine will receive each treatment 28 times

Selection of Cut-In Speed

• Selected 5.0 m/s

– Well studied & known reduction level (avg 50% reduction)

– Being considered/implemented in HCPs, including the MSHCP

– Benchmark for deterrents

Summary Results

• Fatality Monitoring

– Completed 98% of scheduled searches (n = 1,754)

– 95% (n = 36) missed searches caused by weather

• Thermal Video Monitoring

– Completed 83% (n = 93 nights) & 87% (n = 97 nights) of

scheduled video monitoring at 2 wind turbines

• UAD Performance

– UADs performed on 98% of scheduled nights (n = 881)

– On 4 nights, all 6 UADs nonoperational at 1 turbine

– On 9 nights, 1 of 6 UADs nonoperational at 1 turbine

– On 1 night, 2 turbines that were scheduled to be off were on

Comparative Results

-250

-200

-150

-100

-50

0

50

100

150

All Bats Eastern Red Bats Hoary Bats Silver-haired Bats Big Brown Bats Low Frequency Bats

Effe

ct w

ith

95

% C

on

fid

ence

Lim

its

Deterrents Curtailed Both

* * * * *

*Statistically Significant

Location of Carcasses Relative to Turbine

Thermal Video Processing

• BCI continues thermal video data analysis

– Processing data to identify bat targets

– Syncing bat targets between cameras

– Obtaining x, y, & z coordinates

– Creating 3D images of bat flight paths

Results from Experiment in South Texas(TX State University, Duke Energy Renewables, NRG Systems, BCI)

All Bats Brazilian Free-tailed Bats46% (24–67%) 51% (27–75%)

All 14 hoary bat fatalities at control turbines

Conclusions

• Eliminated device issues from previous generation

deterrents

– No overheating or no water entry

• Deterrents did not significantly reduce overall bat fatalities

– Opposite effect for eastern red bats

– Deterrents did not significantly reduce fatalities of low freq. bats

– Inconclusive for other species because of low sample size

• Potential factors include

– Placement of the deterrents

– Species behavior & echolocation

– Sound pattern & intensity

Next Steps

• Thermal video analysis

– May help with placement, orientation & number of deterrents

• Complete reports & prepare manuscripts in 2018

• NRG Systems Webinar: ‘What’s Up With Bat?’

– 11 April 2018; 2 pm (Eastern)

– Overview of NRG’s bat deterrent testing from 2017

– Improvements to the system

– Additional testing for 2018

Acknowledgements

• This material is based upon work supported by the Department of

Energy, Office of Energy Efficiency and Renewable Energy (EERE),

under Award Number DE-EE0007036

– Jocelyn Brown-Saracino, Raphael Tisch, Brad Ring, & Terri Krantz

• Megan Seymour & Keith Lott (U.S. Fish & Wildlife Service)

• Kristin Kerwin & Chris Rowe (U.S. Department of Energy)

• Blue Creek Staff, particularly Neil Voje

• Dan Gordon

• 22 Field Technicians

Discussion