Tides and Tidal Energy JUDITH WOLF MARINE SYSTEMS MODELLING GROUP, NOC
Outline
• Tidal science at Liverpool
• Modelling the tide
• Some tidal energy studies
• Tidal energy atlas
• Joule project – NW tidal barrages (2006-2008)
• Mersey Tidal Power Feasibility Study (2011)
• Development of Scottish Shelf Waters Model for Marine Scotland (2013-2015)
• Ecowatt2050 project (funded by EPSRC, 2014-2017)
• FLOWBEC – X-band radar measurement of tidal currents
• NERC MREKEP
• CORER (Centre for Offshore Renewable Energy Research) established 2014
Tidal science at Liverpool
Liverpool Tidal Institute established 1919 led by Prof Joseph Proudman
https://www.ntslf.org/ National Tidal and Sea Level Facility
AnyTide iPhone and Android App:
http://noc.ac.uk/using-science/products/anytide-app
Tidal Energy Atlas:
http://www.renewables-atlas.info/
based on NOC POLCOMS HRCS model
Wakelin et al.
(2009)
POLCOMS
Atlantic Margin
Model (AMM)
NOC Liverpool
has been
involved in
development of
digital tidal
models
2-D (depth-
averaged), now
3-D since
1970’s e.g.
Flather (1981);
Recently
unstructured
grids e.g.
ADCIRC (2D),
FVCOM (3D
2-D Modelling using ADCIRC unstructured grid model
(Liverpool University, NOC: Joule Project)
Burrows et al. (2009), Walkington and Burrows (2009)
Grid resolution varies from 15km at the ocean boundary to ~50m in estuaries of
interest: Severn, Dee, Mersey, Ribble, Morecambe Bay and Solway Firth 6
Tidal Power Potential of the Eastern Irish Sea Joule Project results (2009): Tidal barrages in the estuaries of the
North West could meet half the region’s present electricity needs. Low water High water
Barrage
Wolf et al 2009
Wolf et al., 2009)
Scottish Shelf Waters Model
Aims and objectives:
• to develop a validated three dimensional baroclinic hydrodynamic model for Scottish shelf waters, for tides and residual circulation;
• to develop a validated three dimensional hydrodynamic model for each of four identified case study areas (Pentland Firth/Orkney Waters, St Magnus Bay, East Coast of Lewis and Harris, Wider Loch Linnhe System
• to develop a validated wave model for the Pentland Firth and Orkney Waters case study area
• to integrate the case study sub‐models into the wider domain shelf model.
The output of the modelling will provide a quantitative description of marine currents and water properties for the whole of Scottish shelf waters on a range of spatial scales, to inform Marine Scotland and aid in marine management and licensing for MRE and aquaculture.
Scottish Shelf Waters (SSW) FVCOM model
extent
Tidal boundary
TPXO7.2
global tidal
inversion from
TOPEX/Poseidon
altimeter data
(Oregon State
University, Egbert
and Erofeeva,
2002).
Snapshot of depth-averaged current vectors, shading
corresponds to water depth, length of vectors (shown
by black bar) corresponds to current speed (0-2.614 ms-
1)
3-14
Tidal currents in the
Pentland Firth from
SSW model
NOC-L HRCS model M2 cotidal chart
3-13
M2 tide from
POLCOMS
HRCS (high
resolution
continental
shelf) model
Tidal Validation
0.5
0.50.
5
0.5
1
1
1
1
1
1
1
1
1
1
1
1.5
1.5
1.51.52
2
22
2
22
2.5
2.5
2.5
3 3
3
4
-10 -5 0 5 1048
50
52
54
56
58
60
All tidal analysis points (N of 54 deg N)
3-15
Tidal Observations
in Scottish Waters
from BODC)
BODC (British
Oceanographic
Data Centre) is
based at NOC
in Liverpool:
www.bodc.ac.uk
Scatter plots of selected M2 amplitude and phase: left –
elevations, right - currents
3-17
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 0.5 1 1.5 2
M2 elevation amplitude
0
60
120
180
240
300
360
0 60 120 180 240 300 360
M2 elevation phase
0
20
40
60
80
100
120
0 20 40 60 80 100 120
M2 semi-major amp
0
30
60
90
120
150
180
0 30 60 90 120 150 180
M2 semi-major phase
18
Development of coupled models
3D Baroclinic Hydrodynamics
Pelagic Model
Benthic Model
Wind Stress - WRF
Irradiation
Cloud Cover
Bo
un
dary
Co
nd
itio
ns
C,N, P,Si
Detritus
Meio-
benthos
Anaerobic
Bacteria
Aerobic
Bacteria
Deposit
Feeders
Phyto-
plankton
Nut
rien
ts
Pelagic Suspension
Feeders
D
e
t
r
i
t
u
s
N
u
t
r
I
e
n
t
s
Oxygenated
Layer
Reduced
Layer
Redox
Discontinuity
Layer
Phytoplankton
Zooplankton
Pico- Flagellates Diatoms
Dissolved
Particulates
Bacteri
a
Micro- Meso- Hetero-
trophs
Small Cells Large Cells
Si
NH4
NO3
PO4
CO2
O
r
g
a
n
i
c
s
N
u
t
r
i
e
n
t
s
Sed S,T,SPM,
K,u,v,w
River
Inputs
Wave Model
Heat Flux
Sustainable use of natural resources
How will barrages, turbines, wind farms and other energy extraction devices affect the flow, hence the sediment transport and ecology?
There may be long term, large area changes in sediment distribution due to changes in tidal flow and waves.
North Hoyle
19
Environmental Impacts
Tides
• Change in tidal regime
• Changes in tidal resource for conjunctive operation of large arrays
• Environmental modification • Intertidal area
• Turbulence and Mixing
• Sediment transport, water quality, morphology
Structures may provide habitats and enhance biodiversity
EcoWatt 2050 (EPSRC): 2014-2017
Led by Prof Jon Side, Heriot-Watt, Orkney
• We will use the Marine Scotland SSW FVCOM model – the validated
model has been delivered to MSS and will be provided to the project
• Coupled 3D hydrodynamic/wave/ecosystem model to be provided by
NOC
• Implement large-scale tidal stream arrays, using the TeraWatt
methodology and run for present day and future climate
NERC MRE KE programme (hosted at NOC
April 2011-March 2015, led by Paul Bell)
Strategic Objectives: To ensure NERC funded research outcomes generate beneficial impact for the economy, environment and society
• Enhancing and protecting the environment
• Maintaining and enhancing health and wellbeing
• Increasing income, savings, efficiencies, resilience and reducing risk
• Ensuring a strong conduit from research outputs to industry, policy and societal needs http://noc.ac.uk/science-technology/marine-resources/energy/marine-renewables/knowledge-exchange-programme
24
CORER – Centre for Offshore Renewable Energy
Research (NOC, Universities of Southampton and
Liverpool, Ocean University of China, Qingdao
25
www.corer.org