Tidal Stream Turbines

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Tidal Stream Turbines

• Dr Ian Masters
• Finance Director
• Swanturbines Ltd.
• www.swanturbines.co.uk

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Harnessing the tidal stream

• Predictable
• Generation pattern is known
• Invisible
• Devices below waterline
• Economic
• Cost drops to base load price with volume
  installation
• Diversification of an existing renewables
  portfolio
• Immediate
• Technology is ready to be installed now

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Learning from History Wind

• Those who refuse to learn from history
• are condemned to repeat it.
• George Santayana
• The Danish Government spent 500m over 20 years
  to get 50 of the 4bn pa world wind market
• Tidal stream energy is potentially the same
  market size.

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Value of Tidal Stream for Wales

• Industrial capacity and knowledge base exists
• Good infrastructure (transport, manufacturing and
  coastal grid connection)
• New supply chain for new industry
• Export market
• Security of supply tide will always be there!
• The potential in Wales from tidal and wave
  projects by 2025 could be more than half of our
  current electricity consumption.
• -Renewable Energy Route Map for Wales, 2008.

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• The most economic tidal stream energy technology

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concept

• Simple, robust, economic
• Design out complexity
• Offshore ? maintenance a large cost
• Careful design ? more profit
• Direct drive
• Fixed pitch
• Variable speed
• Completely submerged

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• Major accomplishments to date

• 8 years development
• 2.3m spend to date
• Strong IP (At PCT stage, 3 patents filed)
• 14 staff
• Expert consortium partners
• Prototype turbine river tested
• Manufacture of demonstrator started

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Development Timeline
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Technology Demonstrator
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concept

• Simple, robust, economic
• Design out complexity
• Offshore ? maintenance a large cost
• Careful design ? more profit
• Direct drive
• Fixed pitch
• Variable speed
• Completely submerged

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Direct Drive Electrical System
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Hydrodynamic aspects

• Design out complexity
• Offshore ? maintenance a large cost
• Careful design ? more profit
• Fixed Pitch
• Angle of blade to hub does not change
• The pitch bearing/motor/control is very expensive
  on wind turbines
• Integrated design of blade and generator
  maintains efficiency
• Blade Element Computational Model to capture
  whole system in a real (tidewaves) sea state.

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Environmental Impacts - Minimal

• Interaction with marine mammals
• Slow moving blades an obstruction to flow
• Visible in water
• Extensive monitoring to take place at EMEC
• Changes to flow patterns
• Some localised effects on water velocity,
  sediment transport etc.
• Noise
• Construction. Very similar to offshore wind farms
• Operational. Close to background levels

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Site Development
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• Tidal Stream Site Selection Procedures and
  Development for a Demonstration Site within the
  Bristol Channel
• A collaborative project between Cardiff and
  Swansea Universities with technical input from
  Swanturbines
• Miles Willis1, Ian Masters1, Sara Thomas1,
  Rebecca Gallie1, Jo Loman1, Andy Cook1, Roger
  Falconer2, Reza Ahmadian2, Guanghai Gao2, Mark
  Cross3, Nick Croft3, Alison Williams3, Medzid
  Muhasilovic3, Ian Horsfall4, Rob Fidler4, Chris
  Wooldridge5, Ian Fryett5, Paul Evans5, Tim
  ODoherty2, Daphne ODoherty2, Allan Mason-Jones2
  
• 1 Marine Energy Research Group, School of
  Engineering ,Swansea University
• 2 Institute of Sustainability, Energy and
  Environmental Management, Cardiff University
• 3Civil and Computational Engineering Centre,
  School of Engineering, Swansea University
• 4 School of Environment and Society, Swansea
  University
• 5 School of Earth, Ocean and Planetary Sciences,
  Cardiff University

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• THE CASE STUDY
• Task
• To choose a site typical of that required for
  tidal
• stream turbine deployment.
• Engage with stakeholders.
• Obtain permissions to work.
• Carry our field surveys.
• Design and determine Protocols.

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• Mean Spring Peak Velocities in Wales

ABP Marine Environmental Research on behalf of
Countryside Council for Wales
DTI Tidal Atlas
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• Candidate Sites

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Favourable Bathymetric and Geotechnical Conditions
Proximity to Grid Connection
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Proximity to Port Infrastructure
Navigational Channels
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Proximity to Other Restricted Areas
Proximity to Environmentally-Sensitive Areas
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Conflict With Existing Marine Activities in the
Estuary

• Cables (existing, old and planned)
• Pipelines
• Interconnectors
• Dredging
• UK Mineral Rights
• Round 1 and 2 Wind Farms
• Dumping Grounds

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Comparative size of 15m x15m square base
1km2 Sites
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Traffic Survey Severn Estuary/Bristol Channel
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Navigational Clearance
Storm surge level 17.50m
Max wave peak 15.90m
HAT 13.50m
HW-4hrs pilot boarding 2.0m
LAT 0.00m (Chart Datum)
Min wave trough -2.4m
Min clearance from hub case
Min clearance from blade
51o 21.03N. 3o 20.58W 23th July 2008 1125BST
Optimal hub height
Mudline -30.00m
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Field Work Activities
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Field Work Results
Swathe sidescan of 1km2 candidate site with
measured current flows throughout the water column
Bathymetry along Welsh Coast on Ships of
Opportunity
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Field Work Results 2
Abundance of targets throughout the water column
at the candidate site
Fish detection and positioning at site
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Computer Modelling Results

Mass scour rate on the sea-bed for a turbine
rotor with a cuboid and a cylindrical pile
Iso-surface of pressure gradient around a tidal
stream turbine operating in 2ms-1 current.
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Estuary Scale Modelling Results
Tidal stream turbine array
Suspended sediment with barrage
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Site Development Study - Results

• A multidisciplinary approach is essential to
  determine the environmental impact of tidal
  stream turbines.
• Specific deployment sites will have their own
  constraints, be it environmental or physical and
  as such must be treated individually.
• The site chosen was a well-mixed water column
  with suspended sediment.
• Sediment scour and/or deposition around the pile
  or associated with the turbine blade was not
  considered an issue at this site.
• Fish detection studies showed that what fish were
  present were predominantly in areas away from the
  turbine.
• The oceanographic data collected has been input
  into a variety of Computational Fluid Dynamics
  (CFD) codes to determine interactions of turbines
  with their environment.

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Conclusions

• Tidal and wave energy has vast potential
• 15-20 of UK electricity
• Will be a significant renewable energy source in
  future (larger than the m wind industry?)
• The UK should take the opportunity to invest and
  become the world leader in this growth export
  market
• Next Stage for Swanturbines
• Install a demonstration device at the European
  Marine Energy Centre, Orkney

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Most Economic Tidal Energy

• Simple
• Robust
• Economic
• Predictable
• Invisible
• Low impact
• Modular
• www.swanturbines.co.uk

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Grid Strengthening

• Most of the resource is in north Scotland
• Most power is used in the South East
• Grid needs to be improved significantly