Tides and Tidal Energy JUDITH WOLF MARINE SYSTEMS MODELLING GROUP, NOC

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 (20) Development of Scottish Shelf Waters Model for Marine Scotland (203-205) Ecowatt2050 project (funded by EPSRC, 204-207) FLOWBEC X-band radar measurement of tidal currents NERC MREKEP CORER (Centre for Offshore Renewable Energy Research) established 204

Tidal science at Liverpool Liverpool Tidal Institute established 99 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

NOC Liverpool has been involved in development of digital tidal models 2-D (depthaveraged), now 3-D since 970 s e.g. Flather (98); Recently unstructured grids e.g. ADCIRC (2D), FVCOM (3D Wakelin et al. (2009) POLCOMS Atlantic Margin Model (AMM)

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 5km at the ocean boundary to ~50m in estuaries of interest: Severn, Dee, Mersey, Ribble, Morecambe Bay and Solway Firth 6

Joule Project Tidal results Power (2009): Potential Tidal barrages of the Eastern in the estuaries Irish Sea 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).

Tidal currents in the Pentland Firth from SSW model Snapshot of depth-averaged current vectors, shading corresponds to water depth, length of vectors (shown by black bar) corresponds to current speed (0-2.64 ms - 3-4

0.5 Tidal Validation 60 58 56 2 0.5 0.5 M2 tide from POLCOMS HRCS (high resolution continental shelf) model 54 2 2.5.5 2 0.5 52 2 2.5 50.5 2 2.5.5 33 4 2 2.5 3 48-0 -5 0 5 0 3-3 NOC-L HRCS model M 2 cotidal chart

BODC (British Oceanographic Data Centre) is based at NOC in Liverpool: www.bodc.ac.uk Tidal Observations in Scottish Waters from BODC) 3-5 All tidal analysis points (N of 54 deg N)

2.8.6 M 2 elevation amplitude 20 00 M 2 semi-major amp.4.2 80 60 0.8 0.6 40 0.4 0.2 20 0 0 0.5.5 2 0 0 20 40 60 80 00 20 360 M 2 elevation phase 80 M 2 semi-major phase 300 50 240 20 80 90 20 60 60 30 0 0 60 20 80 240 300 360 0 0 30 60 90 20 50 80 3-7 Scatter plots of selected M 2 amplitude and phase: left elevations, right - currents

M2 tidal elevation, % error in amplitude 3-2

M2 tidal elevation, absolute phase error 3-22

Comparison of observed and modelled tidal current ellipses 3-20 M2 tidal ellipses, W Scotland

Tidal Stream Annual Power Density (kw/m 2 )

Boundary Conditions Development of coupled models Wind Stress - WRF Wave Model Irradiation Heat Flux Cloud Cover Pelagic Model River Inputs O r g a n i c s Particulates Small Cells Dissolved Bacteri a Phytoplankton Pico- Flagellates Diatoms Heterotrophs Micro- Large Cells CO 2 Meso- Si NO 3 NH 4 PO 4 N u t r i e n t s Zooplankton 3D Baroclinic Hydrodynamics 8 S,T,SPM, K,u,v,w Benthic Model C,N, P,Si Detritus D e t r i t u s Aerobic Bacteria Anaerobic Bacteria Suspension Feeders Meiobenthos Phytoplankton Deposit Feeders Sed Nut rien ts N u t r I e n t s Pelagic Oxygenated Layer Redox Discontinuity Layer Reduced Layer

9 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

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): 204-207 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

European Marine Energy Centre (EMEC) tidal site FLOWBEC study site (Orkney, Falls of Warness)

Flood and Ebb Currents at EMEC tidal site using X-band radar (Paul Bell, NOC Liverpool)

24 NERC MRE KE programme (hosted at NOC April 20-March 205, 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/marinerenewables/knowledge-exchange-programme

CORER Centre for Offshore Renewable Energy Research (NOC, Universities of Southampton and Liverpool, Ocean University of China, Qingdao 25 www.corer.org