Ecological Perspectives on Offshore Wave Energy Development in the Pacific Northwest: The Big Picture

Transcription

1 Ecological Perspectives on Offshore Wave Energy Development in the Pacific Northwest: The Big Picture The Wildlife Society, Oregon Chapter Salishan Lodge, February 10, 2009 Gregory McMurray Principal Marine Scientist Oregon Coastal Management Program Department of Land Conservation and Development

2 A Sea of Change 2004

3 A Sea of Change 2008

4 Basis for This Presentation MMS released Worldwide Synthesis and a programmatic EIS in 2007 Best information presently available on wave energy is the Scottish Executive s 2007 Strategic Environmental Analysis NOAA has published a wave energy ecological effects workshop proceedings targeted to the Pacific Northwest New assessment from the California Energy Commission recently released Baseline and monitoring studies for the Reedsport Wave Energy Project Settlement will soon to be submitted to FERC Note all these analyses are prospective

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7 Status of FERC Preliminary Permits on the Oregon Shelf This permit just accepted by FERC, but OPT claims they will surrender it.

8 Language of Environmental Risk Assessment (EPA 1992) Stressors and their manifestations (also known as signatures) Receptors Exposure Effects (response) Mitigation (effects avoidance) Residual effects (from SEA) Cumulative effects

9 Point Absorber The Stressors Oscillating Water Column Attenuator Overtopping

10 The Receptors (A System)

11 Wave Energy Buoy An Example

12 The Stressors: Focus Is on Novel Signatures or Combinations from Project Actions Emplacement mainly temporary disturbances (e.g., benthic smothering) Operation The buoys themselves The transmission system The anchoring system Decommissioning Routine and emergency maintenance

13 A Matrix Approach

14 Major Issues by Stressor Wave and current modification New hard structures water column and benthic Chemical toxicity Acoustics Electromagnetic fields Also cumulative effects And use/user conflicts

15 Assessing Potential Effects Source: HT Harvey & Associates

16 Arrays A First Look

17 Array Effects Depending on signatures and additive or multiplicative effects, arrays may create an ecological barrier Depending on process, could also result in a volume swept clear (i.e., like a net) Array will also have a set of characteristic permeabilities Key receptors for array effects: Animals with crossing migration patterns Predators or prey utilizing new structure Animals with susceptible life histories

18 Wave and Current Matrix

19 Wave and Current Modification Estimates of 3-15% wave energy reduction major uncertainty many variables Offshore distance of 2 miles appears to minimize any shadow effect Siting in littoral cell could be quite important Key receptors: Waves themselves (height and energy) Littoral processes Sediment transport near array may create areas of scour in shallow water (<25m) Benthic habitat near array

20 Initial Wave, Current And Sediment Transport (Screening) Study

21 Non-linear Responses From Lohse, et al. 2008

22 New Hard Structures Fish Attraction Device (FAD) effect Invasive Species (e.g., tunicates) Collision danger for larger vertebrates or soft bodied organisms Key receptors: Fouling Community Fish and other nekton Seabirds Marine mammals

23 Chemical Toxicity Spills hydraulic; fuel from boats Biofouling coatings (Cu, Sn) Sacrificial anodes (Zn) Lead and/or other toxics in transmission system Key receptors: Fouling community Infauna (in the case of ablative coatings, especially persistent metals)

24 Acoustics One of best known processes in ocean Complex behavioral responses of vertebrates add greatly to uncertainty QinetiQ studies used human health criteria as proxy Limited hearing loss threshold Permanent hearing loss threshold Key receptors: Fish Seabirds Marine Mammals

25 Acoustics 2 In-water hearing thresholds Source: Richards, SD, EJ Harland and SAS Jones Underwater Noise Study Supporting Scottish Executive Strategic Environmental Analysis of Marine Renewables. QinetiQ. Dorchester, UK.

26 Array Effects - Acoustics Source: Richards, SD, EJ Harland and SAS Jones Underwater Noise Study Supporting Scottish Executive Strategic Environmental Analysis of Marine Renewables. QinetiQ. Dorchester, UK.

27 Array Effects - Acoustics Source: Richards, SD, EJ Harland and SAS Jones Underwater Noise Study Supporting Scottish Executive Strategic Environmental Analysis of Marine Renewables. QinetiQ. Dorchester, UK.

28 Electromagnetic Fields Electrical (E) field and magnetic (B) field Elasmobranchs use electrical fields to locate prey levels of µvolts) Salmon likely use magnetic fields Key receptors: Sharks and rays Prey (including seals and surfers?) Salmonids (ESA species on West Coast)

29 Examples of Mitigation For collisions: Color Spacing Acoustic avoidance devices No surface or subsurface traps For electromagnetic fields: Cable trenching and shielding Alternating current above ~7-8 Hz Faraday cage

30 Faraday Cage 1

31 Faraday Cage 2

32 Cumulative Effects Effects across all receptors systems view Effects of multiple deployments (arrays) Effects of size of individual arrays Effects of multiple arrays Effects of wave energy plus other existing and new uses Measuring effects in a changing ocean Initial study funded by Oregon Wave Energy Trust will take place during 2009 Greg s two key questions: How big an array is too big? How many such arrays is too many in a region?

33 Use and User Conflicts Fishing (commercial and recreational) Salmon trolling Crabbing Shrimp trawling Sport salmon and rockfish Navigation/Transportation Surfing Effect on wave amplitude and period Attraction of sharks Other recreation (e.g., whale watching) Marine reserves (ongoing effort in Oregon)

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35 Major Knowledge Gaps Array effects across the board Hard substrate effects in a softbottom environment Barrier effects Collision risk for large vertebrates System survivability Ecological costs of avoidance

36 Summary Take Home Many generic effects are known and can be roughly predicted or modeled Effects will be time- and location-specific Some effects will be technology-specific Vertebrate behavior/responses are complex and may be species-specific Many major information gaps need to be filled Some forms of mitigation are known and expected to be effective Siting is particularly important for array effects User conflicts may be more likely than ecological effects to limit WEC development

37 System Survivability: Update on Finavera Test Buoy

38 Blub, blub, blub! (buoy sinks during November 2007 recovery attempt)

39 Fast Forward to June 2008

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41 Thanks. Questions?