Wind Farm Design When other wind farms are close

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Wind Farm Design When other wind farms are close

• Arno J. Brand

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Motivation

• Source Rem Koolhaas' Office for Metropolitan
  Architecture (OMA)

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Motivation
Source Noordzeeloket
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Day-ahead
Motivation
Source Wind Service Holland
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Motivation
Source DONG Energy
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Large offshore wind farms may affect each others
wind resource
Motivation
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Can we design a wind farm when other sites are
close?
Challenge
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Can we design a wind farm when other sites are
close?
Challenge

• Yes
• How?

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Can we design a wind farm when other sites are
close?
Challenge

• Yes
• How?
• By determining the local wind climate
• How?

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Can we design a wind farm when other sites are
close?
Challenge

• Yes
• How?
• By determining the local wind climate
• How?
• By modelling planetary boundary layer flow with
  wind farming

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Conclusion
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Outline

• Concepts
• Approach
• Validation
• Predictions

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Design parameters
Concepts

• Wind farm design parameters
• ? Farm separation distance
• ? Turbine spacing
• ? Hub height
• ? Rotor diameter
• ? Nominal power
• Meteorological design parameters
• ? Geostrophic velocity
• ? Geostrophic height
• ? Surface roughness length

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Design parameters
Concepts
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Design parameters
Concepts
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Impact parameters
Concepts

• Velocity deficit
• Velocity recovery distance
• Minimum safe distance
• Disturbed sectors

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Velocity deficits and recovery distances
Concepts
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Spanwise recovery distance
Concepts
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Velocity deficit
Concepts
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Minimum safe distance
Concepts
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Disturbed sectors
Concepts
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Disturbed sectors
Concepts
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Disturbed wind rose
Concepts
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Flow solver
Approach

• Neutral planetary boundary layer flow with wind
  farming
• ? Steady and two-dimensional
• ? Equilibrium between convective and Coriolis
  forces
• ? and vertical and spanwise turb. mom. flux
  gradients
• ? and forces due to the wind turbines
• Numerical representation
• ? Implicit solution in the vertical
• ? Marching solution in horizontal directions
• ? Implicit Lagrange multiplier velocity
  correction

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Flow problem
Approach
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Velocity decomposition
Approach

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Vertical and horizontal length scales
Approach

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Length and velocity scales
Approach
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Governing equations
Approach
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Layout of grid cells
Approach
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Decay of velocity deficit
Approach
Inspiration R.J. Barthelmie et al., 2008, EWEC
2008, Brussels, Belgium
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Decay of velocity deficit
Validation
?Wfarm,ini and m from calculations
and measurements
Inspiration R.J. Barthelmie et al., 2008, EWEC
2008, Brussels, Belgium
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Grid-cell versus one-point velocities
Validation
Translation
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Horns Rev wind farm
Validation
Grid-cell values
One-point values
Source DONG Energy
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Nysted wind farm
Validation
Grid-cell values
One-point values
Source DONG Energy
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Velocity profile without a wind farm
Predictions
geo region
logarithmic layer
sub layer
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Velocity profile without a wind farm
Predictions
geo region
logarithmic layer
sub layer
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Velocity profile near a hypothetical wind farm
Predictions
velocity deficit
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Conclusion
Predictions
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• Extra

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Momentum equations
Approach

• Discretisation
• Representation
• Solution procedure
• Formal order of method
• Numerical stability
• Conservation of mass and energy

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Other aspects
Approach

• Lagrange-multiplier approach
• Turbulence parameterization
• Wind turbine parameterization
• Initial and boundary conditions
• Discretization error estimation

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Impact of nominal power density on initial
velocity deficit
Predictions
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Impact of nominal power density on velocity
recovery distance
Predictions
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Summary
Summary