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

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

Tidal Energy Overview Industry Challenges Site Characterization Evaluating Environmental Effects

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

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

“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

Tidal Hydrokinetic Devices

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

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

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

Tidal Energy Overview Industry Challenges Site Characterization Evaluating Environmental Effects

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

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

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

Cost of Energy Marine renewables more expensive than terrestrial alternatives Wave energy: 200-700 $/MWh Tidal energy: 150-600 $/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

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

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

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

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

Tidal Energy Overview Industry Challenges Site Characterization Evaluating Environmental Effects

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

Seabed Characterization

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)

Deployment Time Lapse

Rough Deployment

Tidal Energy Resource Idle Operating

Sources of Ambient Noise

Deep Water Screening Experiment

Large Annual Variability

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

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

Tidal Energy Overview Industry Challenges Site Characterization Evaluating Environmental Effects

Existing Anthropogenic Noise Automatic Identification System (AIS)

Received Levels from Passenger Ferry Sea Spider deployment

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

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

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.

More information available at: Thank You More information available at: http://depts.washington.edu/nnmrec