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Modelling Changes to Physical Environmental Impacts due to Wave - - PowerPoint PPT Presentation
Modelling Changes to Physical Environmental Impacts due to Wave - - PowerPoint PPT Presentation
Modelling Changes to Physical Environmental Impacts due to Wave Energy Array Layouts Helen Smith, Ian Ashton EIMR 2014, Stornoway 20.05.2014 Overview 1. Context: The EBAO project 2. Theoretical modelling study 3. Case study for EMEC 4.
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EBAO
“Optimising Array Form for Energy Extraction and Environmental Benefit”
Scenario A: Constrained channel Tidal Scenario B: Sea area between Tidal mainland and island Scenario C: Inshore site Wave, Tidal Scenario D: Offshore site Offshore wind
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Theoretical model
- 3 array scenarios
- Grid:
- Parallel depth contours
- Real bathymetry (Orkney)
- Deepest device located at 60m depth
- 2 sea states – average and large
- 5 wind scenarios
- All modelling using SWAN spectral wave model
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Theoretical model – Scenario1
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Theoretical model – Scenario 2
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Theoretical model – Scenario 3
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Wind scenarios Following: 5ms-1, 10ms-1, 20ms-1 Opposing: 10ms-1 Cross: 10ms-1
Theoretical model
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- SWAN spectral wave model
- Devices represented as 50m partially transmitting barriers
- Frequency-dependent energy absorption
- Limitations of SWAN?
TrCoeff = HsT/HsI
Theoretical model
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Output
200m 1000m 5000m 10000m Shore Centre
Theoretical model
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Sea state 1, no wind
Theoretical model - results
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- Increasing the number of devices increases the impact
- Clusters of devices with corridors lessen impact closer
to devices, but this becomes negligible by the shoreline
- Impact decreases with increasing following or cross
wind
- Impact increases with opposing wind
- Impact increases at shoreline for steeper seabed
- Impact slightly higher for larger sea state
Theoretical model - summary
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EMEC case study
- 4
- 3.6
- 3.2
- 2.8
- 2.4
- 2
58 58.4 58.8 59.2 59.6 60
- Run over full
year (2005)
- Input data from
EMEC hindcast
- Same 3
scenarios modelled
- Output at three
~10m depth locations
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Location 1
EMEC case study
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Sea state corresponding to ‘small’ sea state, 20/3/05 15:00: Hs = 1.56m, Tm = 5.3s, D = 275°
EMEC case study
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Sea state corresponding to ‘small’ sea state, 20/3/05 15:00: Hs = 1.56m, Tm = 5.3s, D = 275°
EMEC case study
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Sea state corresponding to ‘small’ sea state, 20/3/05 15:00: Hs = 1.56m, Tm = 5.3s, D = 275°
EMEC case study
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Conclusions
- Array layout is important for near-field effects, less so
for the far-field
- Local wind and wave conditions more influential on the
scale of the impact
- Next stage is to examine how these impacts affect
wider physical and ecological scenarios
- Further work ongoing to develop the capability of
spectral wave models to prediction such impacts – need validation!
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