Uncertainties on wind speed measurements can be a limitation in the modelization of a WTG, as discussed by Odgaard et al. [27]. In our case, uncertainties are minimized by the current methodology. First the random error is reduced by taken the ten minute average. Moreover, the weighted average of EWMA and GWMA control charts is acting as high frequency filter. If the anemometer suffers a systematic error, it does not affect our results since we are comparing measured values to an historical reference of the same anemometer. As for developing bias, resulting of a sudden of progressive change in the behavior of the anemometer, the signal will eventually fall outside of the control limits defined by the control charts.