Group 4 – Marine EnergyGroup 4 – Marine EnergyGroup 4 – Marine EnergyGroup 4 – Marine Energy

Marine Current Resource and Technology MatchingMarine Current Resource and Technology Matching

James Glynn Kirsten HamiltonTom McCombes

Malcolm MacDonald

James Glynn Kirsten HamiltonTom McCombes

Malcolm MacDonald

• Investigate the characteristics of the tidal resources in Scotland and demonstrate how to match those resources with the appropriate Marine current technology

• Investigate the characteristics of the tidal resources in Scotland and demonstrate how to match those resources with the appropriate Marine current technology

Project DefinitionProject Definition

Project FlowchartProject FlowchartSTAGE 1

A. Resource Investigation B. Technology Investigation

ii) Vertical axis turbine

iii) Oscillating Hydrofoil

i) Horizontal

axis turbine TOMS software

A. Matching Methodology

STAGE 2

Environmental Impact & Planning

Assessment

B. Case study

Mapping Tidal Data

STAGE 3

Expert system

STAGE 1

A. Resource Investigation B. Technology Investigation

ii) Vertical axis turbine

iii) Oscillating Hydrofoil

Map and profile sites in the West of

Scotland

i) Horizontal

axis turbine

TOMS software

Calculate surface tidal current data for each

site

A. Matching Methodology

STAGE 2

Most suitable velocity distribution for operation

identifiedVelocity distribution calculated for an area of a particular bathymetric

characteristic

Environmental Impact & Planning

Assessment

B. Case study

Use bathymetry of sites to calculate shear profiles and derive velocity distributions

Generic Modelling of three tidal technologies and suitable conditions for deployment

- Define rules to match technology with a particular resource characteristic- Velocity distribution for site matched with suitable velocity distribution for technology

Mapping Tidal Data

Prove robustness of work and further

quantify methodology

STAGE 3

Expert System

A. Resource Investigation - SummaryA. Resource Investigation - SummarySTAGE 1

A. Resource Investigation B. Technology Investigation

ii) Vertical axis turbine

iii) Oscillating Hydrofoil

i) Horizontal

axis turbine TOMS software

A. Matching Methodology

STAGE 2

Environmental Impact & Planning

Assessment

B. Case study

Mapping Tidal Data

STAGE 3

Expert system

•Pentland FirthPentland Firth

•Orkney IslesOrkney Isles

•Butt of LewisButt of Lewis

•Sound of HarrisSound of Harris

•Barra Sound, South UistBarra Sound, South Uist

•Barra Head, South UistBarra Head, South Uist

•Head of ArdmurchánHead of Ardmurchán

•Tiree & CollTiree & Coll

•Firth of Lorne, MullFirth of Lorne, Mull

Strait of Islay & JuraStrait of Islay & Jura

•West Bank IslayWest Bank Islay

•Middle Bank, IslayMiddle Bank, Islay

•Kildonan Pt, ArranKildonan Pt, Arran

•Mull of KintyreMull of Kintyre

Sites MappedSites Mapped

Mapping MethodMapping Method

Velocity Distribution Model ‘TOMS’Velocity Distribution Model ‘TOMS’STAGE 1

A. Resource Investigation B. Technology Investigation

ii) Vertical axis turbine

iii) Oscillating Hydrofoil

i) Horizontal

axis turbine TOMS software

A. Matching Methodology

STAGE 2

Environmental Impact & Planning

Assessment

B. Case study

Mapping Tidal Data

STAGE 3

Expert system

• Bathymetric profiles (channel cross-sections) from mapping data is inserted into TOMS software, ‘Topological Oceanographic Modelling for Shear’.

• This provides shear profiles of flow having inserted values for surface flow and roughness coupled with Manning’s equation.

• The shear profiles enable the velocity profiles for sites of varying cross-section to be calculated

• A simple tool to quickly assess the effect the topography of a sites affects the velocity of the flow

• Bathymetric profiles (channel cross-sections) from mapping data is inserted into TOMS software, ‘Topological Oceanographic Modelling for Shear’.

• This provides shear profiles of flow having inserted values for surface flow and roughness coupled with Manning’s equation.

• The shear profiles enable the velocity profiles for sites of varying cross-section to be calculated

• A simple tool to quickly assess the effect the topography of a sites affects the velocity of the flow

Velocity Distribution Model ‘TOMS’Velocity Distribution Model ‘TOMS’

• Mapped profile

• Horizontal shear influence on velocity

• Vertical shear influence on velocity

• Overall velocity profile

• Mapped profile

• Horizontal shear influence on velocity

• Vertical shear influence on velocity

• Overall velocity profile

Computational Model UpdateComputational Model Update

• Model currently being applied to various areas in the west of Scotland

• Also being validated against known results such as Straits of Messina, currently shows good correlation

• Next step is to include seabed roughness and shoreline effects

• Next week we hope to conclude resource model, show results and use it to develop matching methodology

• Model currently being applied to various areas in the west of Scotland

• Also being validated against known results such as Straits of Messina, currently shows good correlation

• Next step is to include seabed roughness and shoreline effects

• Next week we hope to conclude resource model, show results and use it to develop matching methodology

B. Technology Investigation

Continued …

B. Technology Investigation

Continued …

STAGE 1

A. Resource Investigation B. Technology Investigation

ii) Vertical axis turbine

iii) Oscillating Hydrofoil

i) Horizontal

axis turbine TOMS software

A. Matching Methodology

STAGE 2

Environmental Impact & Planning

Assessment

B. Case study

Mapping Tidal Data

STAGE 3

Expert system

Horizontal Axis Turbine ModelHorizontal Axis Turbine Model

• Able to predict: Blade element forces and

moments Blade element performance

• Thus Torque, power, thrust and

loading of device Device efficiency

• For Plain, common-or-garden

free flow turbines Co-axial, contra-rotating Shrouded (ducted fan) type

MCTs

• In Uniform & non-uniform flow

normal and yawed to the disk plane

• Able to predict: Blade element forces and

moments Blade element performance

• Thus Torque, power, thrust and

loading of device Device efficiency

• For Plain, common-or-garden

free flow turbines Co-axial, contra-rotating Shrouded (ducted fan) type

MCTs

• In Uniform & non-uniform flow

normal and yawed to the disk plane

Oscillating Hydrofoil ModelOscillating Hydrofoil Model

• Standard NACA 0015 Airfoil Section Symmetrical Profile High Lift, Low Drag

• Standard NACA 0015 Airfoil Section Symmetrical Profile High Lift, Low Drag

cVCL l2

NACA 0015 Cl Curve

0

0.2

0.4

0.6

0.8

1

1.2

0 3 6 9 12 15 18 21 24

Angle of attack (Alpha)

Co

effi

cien

t o

f L

ift

(Cl)

NACA 0015 Cl Curve

Drag Coefficient

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0 2 4 6 8 10 12 14 16 18 20 22 24

Angle Of Attack (alpha)

Dra

g C

oef

fici

ent

(Cd

)Drag Coefficient

dACVD 2

2

1 lACVL 2

2

1

•Predict system forces

Specified foil geometry

Optimum angle of attack

Balanced arm Vs foil design

•Resolve system forces

Torque

Sinusoidal angular velocity

Cyclic power output profile

•Dual Foil Generation

Out of phase cycle

Constant power profile

Neutral vertical lift

Environmental Agencies & ImpactEnvironmental Agencies & ImpactSTAGE 1

A. Resource Investigation B. Technology Investigation

ii) Vertical axis turbine

iii) Oscillating Hydrofoil

i) Horizontal

axis turbine TOMS software

A. Matching Methodology

STAGE 2

Environmental Impact & Planning

Assessment

B. Case study

Mapping Tidal Data

STAGE 3

Expert system

• A part of the project is to identify a generic proposal structure that would incorporate the necessary information for all the agencies concerned Found their relevant literature or contacted them Will help us compile criteria; of importance for developers, as an

initial aid

• At first glance, appears that consent process between relevant bodies quite convoluted – authority/overlap unclear On further inspection, doesn’t get better Some potential developers gone elsewhere for easier life..

Iceland, Norway. Some employees we spoke to agreed more standardisation

across the board was required

• At least 6 distinct groups that require a part in the consultation process. Brief rundown:

• A part of the project is to identify a generic proposal structure that would incorporate the necessary information for all the agencies concerned Found their relevant literature or contacted them Will help us compile criteria; of importance for developers, as an

initial aid

• At first glance, appears that consent process between relevant bodies quite convoluted – authority/overlap unclear On further inspection, doesn’t get better Some potential developers gone elsewhere for easier life..

Iceland, Norway. Some employees we spoke to agreed more standardisation

across the board was required

• At least 6 distinct groups that require a part in the consultation process. Brief rundown:

Agencies and their RolesAgencies and their Roles

Scottish Environmental Protection Agency

Environmental Concerns – EIA

MODMOD fully reflects the Government’s policies on ‘Sustainable Development’ In total, the estate comprises some 240,000 hectares (ha) with over 4,000 sites; an area equivalent to about one per cent of the UK landmassSubmarine testing areas etc, of which there are many

Scottish Natural HeritageProvides Government advice- enables energy policy to account for natural heritageDetailed advice is limited - early stages of technology development ‘Outwith areas of high scenic or marine wildlife value, tidal stream generators may offer the potential to generate electricity with lower impacts..’Assessment on marine impact on going. Highest velocity streams off limitsMany Scottish estuaries: wildfowl, land or intertidal areas designated SPAs/ SACs

Agencies and their RolesAgencies and their Roles

Crown EstateOwn waters to territorial limits : 12nm, and to continental shelf: 200nm

Rents/leases sites and grants licenses.

3rd party liability insurance essential

Northern Lighthouse BoardNavigation, danger to surface craft. Request consultation on case by case basis.

Stipulate flasher-buoys, notice to mariners, or mapping for farm deployment etc

Has authority for rejection. EIS with application. Standardised with IALA for RE.

MCA and the DTiApply to DTi’s Offshore Renewables Consent Unit & MCA is their consultation body

Currently updating/creating standards e.g., MGN 275.

Remit is coastal protection (act devolved to SE) & safety at sea. Carry a lot of weight

International Hydrographic Organization (IHO) Order 1 standard multibeam bathymetry survey required, and scale dependent EIS etc

Crown EstateOwn waters to territorial limits : 12nm, and to continental shelf: 200nm

Rents/leases sites and grants licenses.

3rd party liability insurance essential

Northern Lighthouse BoardNavigation, danger to surface craft. Request consultation on case by case basis.

Stipulate flasher-buoys, notice to mariners, or mapping for farm deployment etc

Has authority for rejection. EIS with application. Standardised with IALA for RE.

MCA and the DTiApply to DTi’s Offshore Renewables Consent Unit & MCA is their consultation body

Currently updating/creating standards e.g., MGN 275.

Remit is coastal protection (act devolved to SE) & safety at sea. Carry a lot of weight

International Hydrographic Organization (IHO) Order 1 standard multibeam bathymetry survey required, and scale dependent EIS etc

Studies & RecommendationsStudies & Recommendations• Studies advocate on-going assessment, general consensus at this time

impacts minimal, though many unknowns

• Potential effects: flow patterns, sediment transport, scour, flow reduction significant, marine life, ecology, navigational effects, diving seabirds acoustic emissions, vibrational effects, installation disturbances

• Highlighted Effects in studies shipborne and shore-based radar interference electromagnetic interference Collision risks, shadow effects

• Potential obligations: Refuge in piled structures Site traffic surveys, International navigation Parametric models for seabed disturbance and impact 24h manned control units for emergency shutdown+CCTV

• Studies advocate on-going assessment, general consensus at this time impacts minimal, though many unknowns

• Potential effects: flow patterns, sediment transport, scour, flow reduction significant, marine life, ecology, navigational effects, diving seabirds acoustic emissions, vibrational effects, installation disturbances

• Highlighted Effects in studies shipborne and shore-based radar interference electromagnetic interference Collision risks, shadow effects

• Potential obligations: Refuge in piled structures Site traffic surveys, International navigation Parametric models for seabed disturbance and impact 24h manned control units for emergency shutdown+CCTV

WIP and CompletedWIP and Completed• SIF

..if tidal farms began to significantly reduce the flow in their area, this would have a detrimental effect on the energy output of the farm, something developers will wish to avoid.. DTi (2005)

Advocated approach by RGU and Carbon Trust > Velocity & head loss after extraction etc

• GGS, (Gorlov et al) new Betz limit? Seaflow recorded max 0.6 Cp Chow, Yamell, Manning open channel hydraulics, obstructions, back water,

head loss. Compound spheres of influence, turbulence Investigating maximum extractable portion, and tool development

• Model Validation GH 31MW sound Mull – see how correlates, more like 10MW Velocity models accurate for Sound of Islay and Mull,

• Website, technology modelling, case studies, and the methodology……

• SIF ..if tidal farms began to significantly reduce the flow in their area, this would

have a detrimental effect on the energy output of the farm, something developers will wish to avoid.. DTi (2005)

Advocated approach by RGU and Carbon Trust > Velocity & head loss after extraction etc

• GGS, (Gorlov et al) new Betz limit? Seaflow recorded max 0.6 Cp Chow, Yamell, Manning open channel hydraulics, obstructions, back water,

head loss. Compound spheres of influence, turbulence Investigating maximum extractable portion, and tool development

• Model Validation GH 31MW sound Mull – see how correlates, more like 10MW Velocity models accurate for Sound of Islay and Mull,

• Website, technology modelling, case studies, and the methodology……

Q. Why use an integral rather than a finite difference (numerical) method?

-Numerical methods can make fewer assumptions but relies on excellent input data and a solution is not general. Also it is extremely time consuming. There would have to be a massive number of grid points if all eddy (1dm-1km) scales are to be solved on the grid.

Q. What are the problems with existing data?-Scarcity: tidal data is available, but nearly all studies are based on

surface data, and do not take into account seabed bathymetry. -Resolution: Shallow Water Equation application (and others) are

generally of a 1 minute resolution.-Inverse simulation, by SWE does NOT integrate depthwise so sub-

surface velocity profiles are unknown. Q. What is the effect of the horizontal shear contribution to the velocity

profile?-Negligible in channels where there is very gentle undulation of the

depth across width; not so in channels where there is more severe variation in depth.

Q. Why use an integral rather than a finite difference (numerical) method?

-Numerical methods can make fewer assumptions but relies on excellent input data and a solution is not general. Also it is extremely time consuming. There would have to be a massive number of grid points if all eddy (1dm-1km) scales are to be solved on the grid.

Q. What are the problems with existing data?-Scarcity: tidal data is available, but nearly all studies are based on

surface data, and do not take into account seabed bathymetry. -Resolution: Shallow Water Equation application (and others) are

generally of a 1 minute resolution.-Inverse simulation, by SWE does NOT integrate depthwise so sub-

surface velocity profiles are unknown. Q. What is the effect of the horizontal shear contribution to the velocity

profile?-Negligible in channels where there is very gentle undulation of the

depth across width; not so in channels where there is more severe variation in depth.

Next Steps:

Complete Technology Investigation and start identifying optimum operating conditions

Begin stage 2 Methodology

Next Steps:

Complete Technology Investigation and start identifying optimum operating conditions

Begin stage 2 Methodology

Any Questions?Recurring Questions…

Any Questions?Recurring Questions…