Re-assessment of wake losses

Site: small wind farm in Germany; the client assumes distinctly higher wake losses than calculated in the original assessment report

Procedure: profound analysis of SCADA data, adapted model calculations

Results:

• the met station data used in the wind assessment report turned out to be less appropiate for the site, which is influenced by very local effects, thus the wind rose of the met station is less representative
• the frequency distribution of the wind speed of the met station data is also not representative for the site
• thrust coefficients of the power curve of the wind turbines are too low as has often been observed by aj for this specific turbines manufacturer
• very low turbulence at the site, i.e. the calculated wake losses are too low

Final result: wake losses more than doubled compared to the original calculations