UTK FWF Seminar – Sept 18, 2013

Dr. Mark Bevelhimer

Oak Ridge National Laboratory

Understanding the

Effects of Hydrokinetic

Devices on Aquatic

Organisms

Marine and Hydrokinetic Energy Devices Extract Energy from Water without Dams

www.bourneenergy.com www.atlantisresourcescorporation.com

www.aquamarinepower.com www.wavebob.com

www.openhydro.com

www.newenergycorp.ca

Primary Stressors of Concern Noise

Electromagnetic Fields (EMF)

Physical Encounters (blade strike)

Effects of Concern Injury or death

Behavioral effects (feeding, spawning)

Impediment to movement and migration

Free Flow Power

ORPC

Noise: Field Measurements

Underwater sound emitted from a variety of natural and anthropogenic sources have been recorded and analyzed

Sound levels compared to fish hearing sensitivity

Measurement at operating devices has been a challenge

(AAMI sound analysis software by PNNL)

Noise: Field Measurements

Measured SPL from TidGen turbine at 20m

Relative power spectral densities: • work boat with 25 hp motor • tugboat and barge train • cabin cruiser with diesel engines • rain • ambient background

Noise as a fxn of distance: • passing vessels of various sizes on the Tennessee and Mississippi rivers • predicted levels of the ORPC TidGen turbine as recorded in Cobscook Bay, Maine.

Noise: Field Measurements

Sound fields of three vessels (small boat, cruiser, tug & barge) relative to a 4-turbine MHK array at proposed site on the Mississippi River near Memphis, TN.

Noise: Mesocosm Studies Behavioral responses to recorded HK

device sound evaluated in net pen studies.

Largemouth bass, paddlefish, and pallid sturgeon (7-10 at a time).

Volumes represented distances of 0-60 m from device.

Fish movement tracked by surgically implanted transmitters.

Location data used to evaluate attraction, avoidance, and change in activity.

RESULTS

No consistent trends of attraction or avoidance to the sound at any volume.

Level of activity varied among the 3 species, but no consistent changes in activity in response to sound at any volume.

Floating Net Pen (6m wide x 20m long x 1.5m deep)

Underwater Speaker

Arial view of sound levels in net pen at V=6 setting (SPL range 126-140 dB)

EMF: Laboratory Studies

SHORT-TERM EXPOSURE METHODS

1 fish per tank in both treatment and control aquaria

Treatment tanks with 1 of 2 magnet types on one side of tank

Half-pipe cover provided on each side

46-hr observation recorded on digital video imaging system

Location evaluated every 5 min

Location and activity levels compared between magnet exposure and control

EMF: Laboratory Studies

SHORT-TERM EXPOSURE RESULTS

Responses among species and magnets were inconsistent

Redear sunfish showed a significant but slight attraction to both magnets.

Fathead minnows increased activity with magnet exposure.

EMF: Laboratory Studies

IMMEDIATE EXPOSURE METHODS

Electromagnet with variable control

Circular tank and high-speed camera (250 frames/sec)

One fish tested at a time; 5 trials/fish/treatment

Various magnet strengths (100%, 50%, 25%, 5%, 4%, 1%, 0%)

Magnet and camera activated for 4 sec

Abnormal behaviors noted as fish encounter magnet

Magnet strength reduced until ‘no effect’ observed

Lake Sturgeon

Acipenser fulvescens Paddlefish Polyodon spathula

EMF: Laboratory Studies IMMEDIATE EXPOSURE RESULTS

Lake sturgeon consistently reacted to high levels of EMF (25-100% full strength).

Responses diminished at levels below about 5,000 µT and were normal at 700 µT.

Paddlefish showed no abnormal responses to EMF exposure.

(Bevelhimer et al. 2013 Transactions of the American Fisheries Society)

Lake Sturgeon response was frequent and obvious

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EMF: Mesocosm Studies

Pond studies with similar design as noise studies.

EMF provided with electric cable that runs under net pen

Pallid sturgeon and largemouth bass tests recently completed

Results not yet analyzed

Floating Net Pen (6m wide x 20m long x 1.5m deep)

Underwater Speaker

Onshore

power

source

Application of Results

EMF Example: Minimizing the amount of transmission cable that crosses migration pathways by aligning in parallel with migration direction or by burial will decrease impacts on sturgeon.

river deployed turbines

BAD! GOOD!

Probability of Encounter:

Avoidance, Attraction, or Random Encounter

Probability of Being Struck

if Encountered

Probability of Injury if Struck

by Blade

Blade Strike: Laboratory Experiments, Field Observations, and Modeling all play a part

Lab studies with Alden &

EPRI

Future field studies with

Verdant Power

Modeling studies at

ORNL

Blade Strike & Injury: Modeling

From Cada et al. 2009

Function of Many Variables

Fish Length

Ground speed (velocity)

Number of Turbine Blades

Which part of blade is encountered.

Species-specific habitat choice and movement behavior

Blade Strike & Injury: Alden Lab Study

METHODS

Three species: rainbow trout (2 sizes), white sturgeon, hybrid striped bass

Approach velocities: 5 to 6.5 fps

Survival Tests

Fish released immediately in front of turbine

Evaluated for injury and survival after forced passage

Behavioral Tests

Fish released 2-3m upstream of turbine

Dark and light conditions

Entrainment evaluated with video and acoustic cameras

Free Flow Power

Half scale, 1.5m diam

Blade Strike & Injury: Alden Lab Study

RESULTS

High survival rates for the species and size groups evaluated (typically 98 to 100%).

Injury/descaling ranged from 0-27% depending on size and species

Behavioral tests demonstrated a high degree of turbine avoidance (86 to 100%) for trout and sturgeon and moderate rates of avoidance for striped bass (32 to 65%).

Avoidance same during night conditions as day

When survival rates are combined with avoidance rates, total passage survival estimates were typically very high (99-100%).

Rainbow trout swimming in front of turbine

Upcoming Study: Field Observations of Turbine Encounter Tidal Array in the East River, New York City

Verdant Power’s RITE Project

Upcoming Study: Field Observations of Turbine Encounter

Multiple sonar units collected fish data near operating turbines

Data analysis objective: Determine fish densities and swimming

direction in the area relative to tidal flow and turbine locations.

Upcoming Study: Field Observations of Turbine Encounter

Multi-beam acoustic camera aimed at single turbine

Data analysis objective: Document behavioral

response of fish that encounter turbine including

incidence rate of turbine passage.

Preliminary Impressions

BLADE STRIKE

Probability of encounter for most fish is likely low

Likelihood of strike and minor injury is moderate

However, more studies needed, especially at deployed devices

NOISE

Probably little risk of impact on freshwater species in already noisy riverine and tidal environments

Might be a different story for marine species and under full deployment of an array of dozens of devices

EMF

Response among freshwater fishes is species-specific

Behavioral effects at high EMF levels or in close proximity to sources

More testing needed to understand if EMF might have significant effects or is just a nuisance

Acknowledgments

U.S. Dept. of Energy Office of Energy Efficiency and Renewable Energy, Wind and Water Power Technologies Program

Pacific Northwest National Laboratory

Alden Research Laboratory

Electric Power Research Institute

Tennessee Wildlife Resources Agency

For more information contact Mark Bevelhimer at bevelhimerms@ornl.gov