Ecological Effects of Wave Energy
Development in the Pacific Northwest
A Scientific Workshop
Workshop Summary (Downloadable PDF)
The State of Oregon is
interested in developing the capacity to harvest wave energy off its coast as a
clean, renewable resource. An
important part of moving this agenda forward must include understanding the
potential effects of wave energy technology on the ecological and physical
components of our coastal ecosystems.
A workshop to address these issues was organized by a steering committee
at the Hatfield Marine Science
Center in Newport, Oregon, on October 11-12, 2007. Below we offer some initial
findings from the workshop. The
proceedings of the workshop will be published as a NOAA Technical Memorandum
available in early 2008. Further
information, including the workshop agenda, participants, and background
documents, is available on the workshop website at: http://hmsc.oregonstate.edu/waveenergy/
Organization of the
A diverse group of some 50
marine scientists from around the country worked to i) develop an initial
assessment of the potential impacting agents and ecological effects of wave
energy development along Oregon’s coast, and ii) develop a general conceptual
framework of physical and biological relationships that can be applied to
specific wave energy projects. To
accomplish these goals, we utilized a series of breakout sessions to determine:
1) What is known about important wave energy parks and
their associated components (such as cables, anchors, buoys) and their effect
on the physical and biological components of the ecosystem?
2) What is unknown about these relationships, including
identification of key information gaps?
3) What is the level of uncertainty, or level of
agreement, among scientists about these interactions?
4) Can we prioritize important ecological issues (e.g.,
5) What studies, monitoring, or mitigation measures
should be employed to help minimize effects?
Two sets of breakout
sessions were convened – the first dealt with “receptors,” or those
elements of the system where significant concern exists. The second focused on “stressors,”
those factors that may change as wave energy systems are installed, operated,
or decommissioned. Information
from each breakout session is currently being synthesized and reviewed by
participants for inclusion in the proceedings volume and development of
workshop recommendations. As a
summary, however, the initial key findings from each group as reported during
the workshop follow:
Receptor Breakout Groups
- There could be significant wave reduction
resulting from wave energy production, with possible beach effects (e.g.,
changes to sediment transport processes).
- There is a need for pilot projects to understand
and model wave reduction effects.
- Mitigation for physical changes should be
developed through analysis of project geometry, density and distance from
- Buoys should not be placed in “sensitive areas”
(i.e., closer to shore than 40m depth).
- Buoys will likely have a minimal impact on phytoplankton.
- There could be positive effects on forage fish
species (attracting larger predators).
- Structures need to minimize loose lines to
minimize entanglement of turtle species.
- Adding structure may induce increased settlement
of meroplankton species.
- Understanding electro-magnetic field (EMF)
effects is important, but effects are currently unknown.
- Wave energy development can have a large effect
on water circulation and currents.
- Current changes would effect larval distribution
and sediment transport (both on benthos and on beaches).
- Fouling community growth on buoys, anchors, and
lines may adversely affect benthic environment if deposited and accumulate
on seafloor (e.g., sloughing off or by routine maintenance of mooring
lines, buoy structures).
- Wave energy development can affect community
structure through changes in species composition and predator effects
(e.g., attraction of predators that were previously absent).
- New structures may affect migration corridors
(e.g., salmon, Dungeness crabs, elasmobranchs, sturgeon, cetaceans).
- There could be potential behavioral effects
through EMF, chemical, and acoustic inputs.
- It is important to evaluate ecological effects
at any wave energy demonstration study sites to reduce uncertainty of
effects (applicable to all receptors).
- Lighting and above water structure may result in
collisions and attraction to buoys.
- Above water buoy structures may alter food webs
and beach processes (affecting shorebirds).
- Data gaps to be filled include spatial and
temporal abundance of birds; bird activity at night; hotspots for birds to
be avoided; important migration patterns.
- There is significant concern about mooring
cables (slack v. taut; horizontal v. vertical; diameter) and entanglement
- Very basic baseline data is needed (mammal
biology, presence/absence/species diversity; information on prey species)
to understand projects’ impacts and long-term buildout scenarios.
- It is critical to monitor cetaceans (e.g.,
videography, beachings, tagging, vessel surveys) to understand how they
interact with wave energy facilities.
Stressor Breakout Groups
- Since energy absorbing structures (e.g., buoys,
wave snakes, etc) affect a suite of receptors, they should not be
established within sensitive habitats and areas (inside 40 m is very
sensitive economically and ecologically; some suggested that wave parks
should stay outside 100 m).
- Impacts can be minimized by working with
industry ahead of time.
- Energy devices that focus or trap water in the
nearshore environment will be especially problematic due to the sensitive
- When addressing impacts, it is important to
distinguish between spills as a source of chemicals (e.g., low probability
but high impact) versus continuous release of fouling paints.
- There is a need for careful baseline and control
sites, which could include sampling multiple sites in time and space to
understand full impacts.
- There is a need to understand effects at
community level—do these bioaccumulate and pass through trophic
- Chemicals can move over large area dependent on
- Critical uncertainties exist: What are the
nature of any toxic compounds to be used? How much could be released? How will receptors
respond? Where will the
- The industry must consider mitigation measures
for devices breaking loose / debris accumulation.
- Important regulations under the ESA, EFH, MMPA,
MBTA must be closely followed as industry develops.
- It is important to understand how new hard
surfaces may change bottom communities (organic inputs, etc.).
- Monitoring efforts need to be attached to the
first large scale project (e.g., OPT project at Reedsport) to be used as a
model for other project development.
- It is important to synthesize existing data and
use it to help answer questions about impacts and identify where important
environmental hotspots are that can be avoided.
- Understanding noise coming from the buoys/cables
and how fish and marine mammals will/could react is critical.
- It is possible to model noise from buoy/cables
and use that information to assess impacts from various scales of wave
energy facility buildout.
- The synchrony of noise from buoys could
exacerbate/create noise not previously considered (this could be modeled).
- Wave energy facilities, depending on their size
and layout, could create a sound barrier that mammals would avoid.
- Some fish species are especially sensitive to
acoustics (herring, midshipman), which could have food chain effects since
some species are prey for other marine mammals.
- Both induced and galvanic E fields are of
- EMF is most likely to affect animals that use
EMF fields for orientation or feeding.
- Induced or galvanic E field are likely to
- Magnetic field is likely to affect orientation.
- Salmon, crab, sturgeon, and sharks and rays (and
albacore under certain oceanographic conditions) are the species most
likely to be affected.
- Major areas of uncertainty exist on the effect
of EMF on receptors.
- Before and after baseline local magnetic field
assessment is needed.
- Controlled experiments are difficult and complex
(confounded with other stressors).
- The workgroup recommends the use of COWRIE
experiments as a guide to value of stressor-response experiments with
- Mitigation (armoring and trenching) is likely
effective for cabling; needs to be a demonstration of Faraday cage
effectiveness in the field for generation devices and subsea (rectifying)
- It is important to understand/evaluate what we
don’t know. As projects scale
up, risks become a function of the extent, density and duration of project
- In order to understand effects, impact
thresholds need to be established.
- As projects scale up in location or
implementation, new risk end points come into play that were not initially
part of the assessment.
Therefore, adaptive management is critical to address long term
- As projects scale up, other activities can be
displaced (e.g., fishing pressure allocated to other areas; may force
whales to alter migration paths, etc.).
- It is important to think broadly about
cumulative effects when assessing impacts.