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Accredited pan-European wind index for the climatological
assessment of the energy yield of wind turbines.
In order to allow planners and operators of wind farms a climatological evaluation of the monthly energy yield, EuroWind is offering the region-related indexing of the monthly wind conditions for the whole of Europe. The EuroWindindex is accredited according to
DIN EN ISO/IEC 17025:2005 and describes
retrospectively
the monthly wind power generation related to the long-term average. The wind index is computed with a horizontal resolution of about 10 kilometers.
Learn more about our EuroWindindex:
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The advantages of the EuroWindindex at a glance |
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Application of a one-of-a-kind, DIN EN ISO/IEC 17025:2005 certified procedure for wind index calculation |
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Maximum quality by using a multitude of representative and continuously controlled wind measuring data |
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Immediate provision of the wind index for the past month at the beginning of the following month each |
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Continuous calculation of the index without a rough classification into regions |
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Determining site-related wind indexes for Germany as well as other European countries |
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Index calculation for individual sites and hub heights |
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Pan-European climatological referencing of annual measurings |
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Climatological representative wind power potentials also in areas where no wind farms had been build yet |
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Procedures
The procedure for wind index calculation is based
on measuring data of selected weather stations. Though
special importance is being attached to the supra-regional
validity of each measuring.
For this purpose 75 measuring stations of the German Weather
Service are available for the Germany-wide wind index.
In addition about 300 selected stations of the national
weather services are included in the European-wide index
calculation.
At the stations the hourly measured wind speeds are processed statistically for each month. By means of this multitude of monthly wind statistics, subsequently the monthly energy yield is being calculated - region-related and for an individual type of turbine with any hub height. The EuroWindindex is formed from the ratio of the current, monthly energy yield and the climatological energy yield.
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Map of
the Germany-wide EuroWindindex for March 2002 |
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Map of the pan-European EuroWindindex for December 2003 |
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Period of averaging
Again and again the question appears which period of
information needs to be drawn on for the wind index
calculation. How can we describe most exactly the current
wind conditions? You will often hear the answer that
this period should amount to at least 30 years. But
is such a long period in fact representative for the
today's wind conditions? Didn't the wind conditions continuously
change due to climate changes in the past decades?
In order to follow up those questions and to be able to perform an optimization of the period under observation for our index calculation, EuroWind has analyzed and evaluated the long-term global wind data of the reanalyzed models of the NCEP/NCAR- and of the ECMWF (ERA-40). The data are available since 1948 (NCEP) respectively 1958 (ERA-40) on a global basis with a regional resolution of about 250 km (NCEP).
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Regional variations of the long-term average wind speeds (NCEP-reanalysis,
1984-2003) |
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The performed trend evaluations show a continuous increase of the average wind speeds in the NCEP data as well as in the ERA-40 data. This phenomenon can mainly be traced back to the increasing climatic warming. It results in an average wind speed which is nowadays by about 0.5 m/s
larger than in the 50ties.
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Chronological sequence of the average wind speed for Germany (ERA-40) |
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Hereof results that a climatological 30-year average value represents the wind conditions of the present only insufficiently. The results show that shorter information periods reflect the current wind conditions significantly more precise. But when selecting the information period it needs to be considered that it is not chosen too short due to the important annual variation of the wind conditions.
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Results
The following graph shows the time series of the EuroWindindex for the years from 1996 to 2004. During this period no clear trend can be spotted for the wind energy yields, also if the year 2003 had been a year of very little wind until end of September.
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Average monthly EuroWindindex for Germany from 1996 to 2004 |
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Validation
The production index of the measured energy yield for a wind turbine Enercon E-66 (1500 kW) in Northern Germany had been compared exemplarily for a period of two years with the EuroWindindex (cf. figure). The average error of the EuroWindindex only amounts to 6.7 %. The average deviation averages to only +0.6 %.
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Comparison of the site-related EuroWindindex with revenue data of an 1.5 MW-plant with a hub height of 98 m |
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Furthermore comparisons had been performed for a number of other wind farm sites. They show the high quality of the EuroWindindex also for sites with complex territory structure.
The EuroWindindex can more over also be drawn on for climatological referencing of short term measuring.
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If we have sparken your interest, please do not hesitate to contact us. We would be pleased to explain you the specialities and
possibilities of our range of services and our internationally accredited EuroWindindex in person.
Call +49 (0) 2234 98 76 23 for personal assistence!
Alternatively, please send us an email to  or use our form below to receive more details and information, thank you!
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