1. Tidal Hydrokinetic Energy WW-ASME Dinner Meeting
Brian Polagye
University of Washington
Northwest National Marine Renewable Energy Center
WW-ASME Dinner Meeting
November 17, 2010

2. 8 Faculty members involved 10 Graduate student researchers supported
Northwest National Marine Renewable Energy Center (NNMREC)
UW-NNMREC
Tidal Energy
OSU-NNMREC
Wave Energy
Resource and Site Assessment
Device and Array Optimization
Testing Facilities
Environmental Effects
Materials Suitability
8 Faculty members involved
10 Graduate student researchers supported

3. Tidal Energy Overview
Industry Challenges
Site Characterization
Evaluating Environmental Effects

4. Tidal Energy Barrage Hydrokinetic Comparable to hydroelectric
Very high cost and environmental footprint
Comparable to wind
Potentially lower cost and environmental footprint

5. Other Forms of Marine Energy
Ocean Thermal
Wave
Ocean Current
Offshore Wind

6. “Typical” Sites and Devices
Gearbox-Generator
Direct Drive Generator
20-60 m
Drive Train
Pile
Gravity Base
Rotor
5-20 m
10-30 rpm
2-4 m/s
Foundation

7. Tidal Hydrokinetic Devices

8. Worldwide Demonstrations
EMEC
OpenHydro
Atlantis
Tidal Generation Ltd.
Voith Hydro
FORCE
OpenHydro
CleanCurrent
MCT
CleanCurrent
Hammerfest Strøm
Pulse Tidal
Voith Hydro
MCT
ORPC
Verdant Power

9. Tidal Energy Projects in Puget Sound
Admiralty Inlet
Pilot project
Race Rocks
Demonstration turbine
Marrowstone Island
Demonstration array

10. Motivation Local Drivers Global Drivers
I-937: 15% renewable energy by 2020
Limited transmission capacity for new wind energy
US Navy target of 50% alternative energy by 2020
Global Drivers
Predictable resource
No CO2 emissions
No visual impact
Close to load

11. Tidal Energy Overview
Industry Challenges
Site Characterization
Evaluating Environmental Effects

12. Tidal Energy Challenges Environmental Effects
Technical Readiness
Societal Concerns
Economic Viability
Environmental Effects

13. Technical Challenges Deep water deployments Maintenance
Most of the resource is in water deeper than 20m
Most wind deployments in water less than 20m
Maintenance
Inspection
Preventative action
Long-term reliability
Moving parts in the marine environment
2+ year service interval for rotor and power train
20+ year service life

14. Shallow Water Biofouling Example
Clean Current turbine
15m depth
6 months deployment
Before
After

15. Cost of Energy
Marine renewables more expensive than terrestrial alternatives
Wave energy: $/MWh
Tidal energy: $/MWh
Ocean thermal energy: 500+ $/MWh
Several contributors to higher cost
Capital cost for extended marine deployments
Operations and maintenance in marine environment
Long and uncertain permitting requirements
Intensive environmental monitoring requirements

16. Environmental Stressors Electromagnetic effects
Cumulative Effects
Energy removal
Device presence:
Dynamic effects
Acoustic effects
Electromagnetic effects
Device presence:
Static effects
Chemical effects

17. Environmental Receptors
Ecosystem Interactions
Marine mammals
Seabirds
Far-field environment
Pelagic habitat
Near-field environment
Fish
(migratory and resident)
Benthic habitat
Invertebrates

18. Barriers to Resolving Uncertainty
Prioritization of effects – 1000’s of combinations
“Chicken and Egg” Problem
Need devices in the water to reduce large uncertainties
Cannot receive permit to operate with large uncertainties
Technology readiness of monitoring
“You can only analyze what you can measure…”
Existing tools focused on stock assessments, not individuals
Significant overlap with fundamental research needs
High natural variability in relation to project scale

19. Existing Uses Tribes Commercial Users Recreational Users Military
Usual and Accustomed Treaty Rights
Fishing and crabbing
Commercial Users
Shipping
Recreational Users
Diving
Military

20. Tidal Energy Overview
Industry Challenges
Site Characterization
Evaluating Environmental Effects

21. Development of Characterization Tools
Shipboard Survey
R/V Jack Robertson
Land Observation
AIS Ship Tracks
Seabed Instrumentation
Measurement Tripod

22. Seabed Characterization

23. Sea Spider Instrumentation Tripod Programmed for 3 month deployments
Acoustic release (redundant recovery)
CTDO (conductivity, temperature, depth, dissolved oxygen – partnership with WA Dept of Ecology)
ADCP
(Acoustic Doppler Current Profiler)
Fish Tag Recorder
(partnership with NMFS)
Hydrophone (background noise)
T-Pod/C-Pod
(porpoise clicks)
Programmed for 3 month deployments
Lead Weight
(650 lbs)

24. Deployment Time Lapse

25. Rough Deployment

26. Tidal Energy Resource
Idle
Operating

27. Sources of Ambient Noise

28. Deep Water Screening Experiment

29. Large Annual Variability

30. Composite Aging Water absorption, leading to loss of strength
In-situ screening tests
9 – 18 months exposure
Four composite material systems

31. IR Detection of Marine Mammals
Lime Kiln State Park
July 5, 2010 at 0350
HD Webcam
IR Camera

32. Tidal Energy Overview
Industry Challenges
Site Characterization
Evaluating Environmental Effects

33. Existing Anthropogenic Noise Automatic Identification System (AIS)

34. Received Levels from Passenger Ferry
Sea Spider deployment

35. Model for Sound Transmission Loss
Source level at 1m
Distance from source
RL = 179 – 18.4 log10(d)
Received level
Transmission loss
coefficient

36. Estimated Project Noise
Two turbines
Source level for each turbine = 160 dB re 1 µPa at 1 m
Same transmission loss model as estimated for ferry
0.5 km
1.0 km

37. Conclusions
Tidal energy is not a “silver bullet”, but will be regionally important.
Significant challenges must be overcome before commercial development.
Opportunity for universities to solve these problems and train first generation of marine energy engineers.

38. More information available at:
Thank You
More information available at: