Assessment of the uncertainty of methods for the extrapolation of wind data to the long term

Sites: Several sites in different European regions with relatively long measured wind data sets

Method:

Calculation of the average wind speed of the entire measurement period based on the data of individual 12-months periods

Results:

• The standard error of the long term mean wind speed determined with the MCP method and the MDP method developed by aj based on time series of 12 months is about 0.1 m/s.
• With linear regressions over monthly means, the uncertainty is higher. Strongly deviating results occurred in some years with this method.
• Based on hourly means, the long term mean wind speeds determined with the MCP method and the MDP method are usually very similar.
• The MCP method allows for calculating a long term time series, whilst the MDP method yields a more accurate long termn frequency distribution and wind rose.
• Gaps in the reference data set can have an important impact on the result.