Knowing the wind speed you can use this to predict your power output for a real turbine. Different turbines are optimised for different locations – the cut in speeds and maxing out speeds varies. Every wind turbine should have a power/wind speed curve. For example there are some here:
http://westwindturbines.co.uk/products/10kwwindturbine.asp. You can feed in the curve data and integrate hourly for a good estimate. However, gustiness will affect it too and I don’t know much about that. Also, obviously you need to have measured the wind speed where the turbine is going to be. Wind speed increases with height above the ground, usually.