The critical element of any wind turbine project is obviously the wind. If you do not have the wind speeds that you first envisaged then there is absolutely nothing that you can do to improve the returns from your project once you have your wind turbine installed.
At the GreenYard, we can report that the majority of sites which we undertake actual measurement of wind speed have overestimated wind data. On average the variance between projected wind speeds (databases) and actual wind speed can be as high as twenty percent less.
On the basis that the power within the wind is a cubic factor, that is if your wind speed doubles the potential power increases eight fold, and vice versa!
Our advice is simple – do not rely upon computer databases to do your homework. Unless you have an exceptionally open site e.g. the centre of Lough Neagh, then you should measure wind speeds.