Windleistungsvorhersage

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Optimal Combination of Different Numerical
Weather Models for Improved Wind Power
PredictionsR. Meyer, M. Lange, U. Focken, M.
Denhardt, B. Ernst, F. Berster European offshore
wind conference exhibition 2007
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Administrative Overview

• Research project 09/2005 09/2007
• Projectcoordinator energy meteo systems GmbH
• Projectpartner German Weather Service RWE
  Transportnetze Strom GmbH
• funded by the Federal Ministry for the
  Environment, Nature Conservation and
  Nuclear Safety
• leads to a
• Development project
• Operational software implementation at RWE by
  energy meteo sytems

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Overview

• Motivation
• Weather Models
• Classification and Combination
• Summary

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Motivation

• Wind power predictions allow energy providers,
  energy brokers, and grid operators to integrate
  the fluctuating input of wind energy.
• Wind power prediction systems commonly use only
  one single numerical weather prediction model
  (NWP).
• But everyday experience shows
• NWP models have strengths and weaknesses in
  different situations.
• Our approach
• Optimal combination of weather models adapted to
  different weather situations.

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European Weather Services
models
GFS
LME
HIRLAM
UMEU
ALADIN
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Previento the physical approach
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root mean square error (rmse) dayahead-forecast
January-October 2005 for single forecasts
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Rule-based Combination Is Required

• Combine and average ... Simple average
  performs as well as more sophisticated
  statistical approaches.
• Clemen, R.T., Combining forecasts A review and
  annotated bibliography, Int. Journal of
  Forecasting 5 (1989) 559-582.
• Rule-based forecasting ... We believe that
  this procedure will lead to improvements.
• Armstrong,J.S., Combining Forecasts The End of
  the Beginning or the Beginning of the End?, Int.
  Journal of Forecasting 5 (1989) 585-588.

use weather information as expert input
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How The CombiTool Works

Model 2
Model 1
Model 3
Model n
etc. ...
Previento
Model X
Previento
Previento
CombiTool 1. Classification of weather
situation 2. optimal Combination
weatherdata
combined wind power forecast
CombiTool
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Weather situation Cyclone passing type A
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Weather situation Cyclone passing type A
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Cyclone passing type A one model is delayed
power inst. power
days
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High pressure Eastern Europe
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High pressure Eastern Europe models differ
power inst. power
days
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Optimal factors differ from situation to situation
normalized average combination factors
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Accuracy in individual weather situations
using optimal weights for each weather situation
leads to considerable improvement
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Combination In Extreme Events
The combination is very benefitial in extreme
events
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Summary

• NWP have strengths and weaknesses in different
  weather situations.
• Just putting together forecasts is not
  sufficient, careful selection needed.
• Automatic classification scheme based on methods
  from synoptic climatology generates useful
  weather classes.
• Optimal combination based on weighting factors
  for specific weather situations outperforms
  individual forecasts.
• Combination avoids large forecast errors in
  extreme events
• The system will be used operationally at RWE.

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Thank you for your attention!
ContaktRonny Meyerenergy meteo systems
GmbHMarie-Curie Straße 126129
Oldenburgronny.meyer_at_energymeteo.dewww.energymet
eo.de
For more Information M. Lange, U. Focken, R.
Meyer, M. Denhardt, B. Ernst, F. BersterOptimal
Combination of Different Numerical Weather Models
for Improved Wind Power Predictions, 6th
International Workshop on Large-Scale Integration
of Wind Power and Transmission Networks for
Offshore Wind Farms, Delft, 2006 Download
www.energymeteo.de
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