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Concepts for offshore wind power estimation
Heinz-Theo Mengelkamp, Sven Huneke, Joachim
Geyer anemos Gesellschaft für
Umweltmeteorologie mbH D-21365 Adendorf,
Germany www.anemos.de
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comparison of two approaches

• extrapolation of coastal wind statistics with
  WAsP
• dynamical downscaling of reanalysis data with
  MM5

wind speed frequency distribution extreme winds,
periods of low/high winds wind shear wind speed
probability / transgression probability ambient
turbulence
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WAsP
no reliable wind statistics no stability depend
vertical wind profile no horizontal wind
gradient over sea no time series information no
thermal effects considered (land-sea
breeze) based on Weibull distributions
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offshore windatlas
?x 4 km
?x 10 km
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windatlas verification
windatlas verification with FINO 1 data 100
m 2004 - 2005 FINO 1 10 min averages ,
windatlas data 30 min averages
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windatlas verification (2004 2005)
wind atlas
FINO I
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long term correlation of FINO I data
adaptation to reference period (1970 2005)
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long term correlation of FINO I data
FINO I data (2004-2005) (1970
2005)
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advantages of the downscaling approach
based on two independent data sets (FINO I, NCEP
reanalysis) comprises high-resolution 3-d
mesoscale modelling (MM5) thermally induced
circulation systems stability dependent
vertical wind profile sea surface roughness
parameterization (Charnok formula) independent
on near-surface measurements horizontal wind
variation over sea provides time series u(t),
P(t) (high/low power duration periods, min,
max, diurnal and annual variations, .) allows
a sound uncertainty analysis comparison of
independent data sets and models comparison of
different reference periods comparison of
realistic and Weibull based f(u)