Transcript Soukissian_A review of the experience on the impacts of energy

A review of the experience on the impacts
of energy from sea (offshore wind,
wave, current-tidal, thermal) on the marine
and coastal environment
Takvor Soukissian
Senior Researcher
Hellenic Centre for Marine Research
Outline
1. Renewable energy sources and technologies
2. The basics
3. The spatial and the temporal scales
4. Environmental stressors & receptors
5. Conclusions
Renewable energy sources and
technologies
Types of renewable ocean energy (Blue energy)
1.
2.
3.
4.
5.
Offshore wind energy
Sea wave energy
Tidal
Ocean current
Thermal energy
BLUE ENERGY 1
Offshore wind
2. Vertical axis wind
turbine
1. Horizontal axis wind turbine
3. Floating (horizontal &
vertical) axis wind turbine
BLUE ENERGY 2
Tides and currents
1. Horizontal axis turbine
2. Vertical axis turbine
3. Enclosed tips
4. Helical Screw
5. Oscillating hydrofoil (6)
6. Tidal kite
7. Other
(7)
(4)
(1)
(5)
(2)
(3)
BLUE ENERGY 3
Waves
(8)
(4)
1. Attenuator
2. Point absorber
3. Oscillating wave surge converter
4. Oscillating water column
(3)
5. Overtopping
6. Pressure differential
7. Bulge wave
8. Rotating mass
(7)
(2)
(1)
(6)
(5)
BLUE ENERGY 4
Thermal gradients
1. Open cycle
1a. Mist lift cycle
1b. Foam lift cycle
2. Closed cycle
3. Hybrid cycle
(1)
(1a)
(2)
(3)
BLUE ENERGY 5
Some blue energy facts
George W. Boehlert and Andrew B. Gill (2010): Oceanography, Vol. 23, No 2.
Social acceptance of
renewable energy
sources in Europe
(Source: European
Commission, 2006)
Definition of the basic constituents
Stressors and receptors
• Stressors are environmental features
subject to change during the various stages
of development of blue energy installations
• Receptors are ecosystem elements with
capability of response to the stressors
Temporal and spatial scales
• Involved time-scales,
• Spatio-temporal extent of the stress
Effects vs Impacts
• “Effect” is a qualitative change which is a
result or consequence of an action or other
cause characteristic
• “Impact” is a marked effect or influence, as
regards the severity, intensity or duration.
There can be positive or negative outcomes to
the effect of the stressor
Effects vs Impacts
The variety of
• blue energy technologies (developed, patented or
under development),
• nearshore or offshore areas and ecosystems,
render the assessment of environmental effects and
impacts very difficult
The temporal scales
For the rational assessment of the construction’s
potential effects/impacts on marine life, appropriate
temporal scales should be defined:
• the short-term temporal scale refers to the
construction and decommissioning phases (of the
order of some months up to a couple of years),
• the long-term scale extends up to the operational
life of the construction (of the order of some
decades) and
• the “permanent” scale, which extends beyond the
operational and the decommissioning phase of the
construction
Design phase (1)
Activities during the preconstruction (design) phase
include:
• general planning and site selection / investigation,
• design of the ocean energy equipment type and the
method of installation,
• consideration of removal options,
• licensing procedures (including Environmental Impacts
Assessment)
• design of the appropriate and necessary mitigation
measures
Planning phase (2)
Information on biotic and abiotic characteristics on the
considered site should be collected and assessed.
Biotic information: marine mammals, sea, resting and
migrating birds, fish species, and macrozoo- and phytobenthos
Abiotic information: sediment characteristics, bathymetry
and geomorphology, geological/geophysical structure at
the site, as well as the general wind, wave and
hydrodynamic climate characteristics of the area
Construction phase (1)
Activities related to:
•
•
•
•
site preparation, dredging and leveling,
piling/installation/anchoring,
cabling, and
shipping and air transports
Construction phase (2)
The disturbances are related to:
• seabed disruption,
• noise and
• increased ship and aerial traffic in the area
Milder disturbances:
•
•
•
•
release of pollutants,
debris and waste,
lighting, (potential effects on bird movements), and
risks related to mariners safety
Operation phase
• Scheduled or non-scheduled maintenance and service
activities take place. The disturbances are related to:
– the physical presence of the device and related infrastructure,
– the operational noise and
– the maintenance activities
• The maintenance activities result in increased traffic in the sea
area and could have disturbing effects on the biota
• Maintenance and repairing materials (paints, covering, chemical
substances, etc). should be treated with caution in order to
avoid chemical pollution
• Potential EMF effects to some fish species, is an open debate
• Bird collisions, especially in the presence of the wind turbines
along migration routes, could be another important effect
Decommissioning phase
Limited existing experience. Two options are available:
• Complete removal of the equipment: The disturbances due to the
presence and operation of the equipment are completely eliminated:
sediment disturbance and loss of the developed habitats during the
operational life of the equipment
• Leaving part of the subsurface structures in place: The installations
would act as permanent structures: any habitats that have been
created and/or habitat disturbance from the physical presence of the
equipment would be maintained. The foundation components shall be
removed until an appropriate depth so as the remaining parts do not
pose a danger for navigation
The spatial scales
The site (1)
Apart of the technical specifications, the specific characteristics of
a location are chosen by assessing and taking into account
potential environmental and socio-economic effects. There are
three different, and usually contradictory, points of view for site
selection:
1) Priority to the geo-morphological and wind, wave, or sea
current characteristics of the area (shallow waters with high
energy resource, ease of access to the shore and grid
connections, etc.) – The engineering/technical point of view
2) Assessing all the different and legitimate marine uses of the
potential sitting area along with other socio-economic effects
– The socio-economic point of view
3) Assessing the potential effects/impacts that the construction is
expected to have to the marine environment – The
environmental point of view
The site (2)
• The planning phase and especially the site
selection procedure is probably the most crucial
and important task: the effects of this decision are
expected to strongly influence the intensity and
the quality of the impacts to the marine
environment
The spatial extent (1)
The spatial extent (2)
• Effects of small energy developments
are localized
• Effects of a single large blue energy
development are significantly
extended in the surrounding space
• Cumulative effects of multiple
energy developments probably
result in completely different sets or
spatio-temporal scales of effects
Environmental Stressors
1.
2.
3.
4.
5.
6.
Physical presence of devices
Dynamic effects of devices
Energy removal effects
Chemical
Acoustic
EMFs
Environmental Stressors
Single small blue energy developments have minor
or even negligible effects
Large energy development have effects extending at
a much greater spatial scale and probably temporal
scale
Physical presence of devices
Sea and migratory birds
– Wind energy devices have the most
significant potential effects
– Wave energy devices have lower
potential for seabird collisions.
Surface devices may have effects to
migratory surface dwellers
Physical presence of devices
Sea habitats and communities:
– The new underwater hard surfaces
will affect bottom communities.
– When deployed in “neutral”
sedimentary bottoms will act as
artificial reefs (settlement habitats)
potentially attracting pelagic
organisms, (“fish aggregation device”)
Dynamic effects of devices:
Blade strikes
– For wind turbines - migratory birds
– For underwater turbines - minor effects
Energy removal effects
• Kinetic energy removal/reduction from water and blockage of flow
due to the physical presence of devices can lead to changes in local
circulation, wave propagation, sediment equilibrium and turbulence
(bottom sediment scouring and habitat changes).
• For nearshore blue energy developments, erosion and/or
deposition may be affected (implications in coastal works and
coastal geomorphology)
• Changes in water flow and turbulence causes changes in
stratification and vertical movements of marine organisms. Removal
of sufficient tidal energy may imply changes in the local tidal range
• For OTECs, impingement and entrainment of species. This is most
probable for warm water intakes (potential impacts on planktonic
and pelagic organisms; more general effects on fisheries).
• Deep cold water is characterized by lower diversity and biomass
Chemical effects
• Increased marine vessel traffic implies additional risks (oil
spills, etc.)
• Anti-fouling paints
• For OTEC, additional concerns emerge due to the ammonia
(working fluid in the closed cycle system), nutrients (that may
be discharged into surface causing algal blooms), higher
heavy metal concentrations (derived from open cycle heat
exchangers or from deep natural sources), alteration of
chemical conditions in the discharge location, acidification
effects, etc.
Acoustic effects
• During the construction phase the pile driving
generates high-intensity/frequency and shortduration noises
• During the operational phase underwater
turbines or hydroplanes add noise to the
underwater environment
• Marine mammals move away from the area
where construction is taking place. At the
operation phase, the mammals usually return to
the area
• Some animals could be attracted to the produced
noise
EMF effects
George W. Boehlert and Andrew B. Gill (2010): Oceanography, Vol. 23, No 2.
• Underwater cables emit low-frequency
electromagnetic fields (EMFs).
• EMF responses were variable between individuals and
indicated an attraction to the route of a subsurface
cable
• Lack of data do not allow an assessment of EMFs
impacts
• There is a high degree of uncertainty as regards the
effect of EMFs on receptors
• Thermal aspects of electricity transmitting cables.
Whether this small temperature change is a stressor is
unknown
Environmental receptors
1.
2.
3.
4.
Physical environment
Pelagic habitats
Benthic habitats / species
Fish / fisheries
Physical environment
• The removal of energy from water
may lead to local acceleration and
scouring, changes in the circulation
and wave propagation patterns,
sediment equilibrium, sediment
transport and erosion/deposition,
coastal geomorphology changes,
etc.
• Currently these processes can be
only simulated
• The operation of OTECs results in
altered thermal regimes at sea
Pelagic habitat
Modification of habitats by creation of new structures
1. Reduced impact on phyto- and zooplankton.
Aggregation of other species and attraction of
predators
2. Blade strike, collision, impingement and
entanglement
3. For OTECs, impingement mortality of planktonic
organisms. Stimulation of blooms due to the
higher nutrient level deep water
Benthic habitat
Habitat changes - modifications to the hydrodynamics of the
area
1. The construction acts as artificial reef (stimulates some
species but may negatively affect others)
2. Artificial hard bottom serves as steppingstones for species
3. Placements in neutral bottoms increase biodiversity and
affect benthic communities (greater predation)
4. The “shell mounds” (buoys, anchors etc.) may constitute
productive fish habitat
5. Changes in the water flow from OTECs may change benthic
communities in the downslope flow. Thermal stresses may
change the benthic community (coral reefs) leading to
structural changes of the habitat
Fish and fisheries
Changes in species composition
1. Attraction of pelagic and benthic species, but also
of predators (increased mortality of local species)
2. Potential exclusion of fishing in the area
3. Noise and EMFs effects
4. Behavioral effects due to EMFs or underwater
noise (especially as regards orientation capabilities
and movement patterns)
5. Migrating fishes may be also affected
Marine birds and mammals
• Increase of energy used by the birds in avoiding blue energy
installations
• Birds avoid wind farm installations (few records of collision)
• Seabirds aggregate near blue energy sites (increased feeding
opportunities)
• Changes to beach processes or tidal amplitudes affect shorebird
foraging
• Lighting potentially results in collisions of seabirds
• Open issues
– Spatio-temporal abundance, bird activity at night, important areas of bird activity,
migration patterns
– entanglement and collision of marine mammals, mammal biology
– acoustics of blue energy devices and EMF effects
The large picture
George W. Boehlert and Andrew B. Gill (2010): Oceanography, Vol. 23, No 2.
CURRENT STATE OF KNOWLEDGE
Conclusions
MOVING FROM THE CURRENT STATE OF
KNOWLEDGE
• To understand impacts, we need to know whether
an effect causes change within a population or
community
• Changes refer to biotic and physical processes and
may be direct or indirect
• Indirect effects are more difficult to be identified
Conclusions
• Need to address the effects of blue energy
• Need to start understanding the potential
impacts
• Research on the environmental effects is far
behind the technological development
• Need for balanced and fair environmental
standards for blue energy devices: avoid risks of
environmental damage and avoid inhibiting the
technological development
Top priority:
MONITORING!
Question:
WHEN, HOW, WHAT, WHERE?
Thank you for your attention