Figuring out what your wind resource is and the best place for a wind generator is vital and difficult. Without a reasonable estimate of the average wind speed at “tower top” (the height at which the turbine will sit), you’ll be making a wild guess about the production of your wind generator. Estimating wind speed is much more complicated and volatile than solar energy predictions, since the resource varies dramatically between rooftop (where it is almost always negligible) to above the trees (where it may be worth capturing).
Short of a full-blown wind study—which is often hard to justify financially for residential sites—two primary resources are often used. First is wind mapping, which might give you reasonable data if you have the expertise to interpret it. Second is already-collected local data, which also needs interpretation, and can range from definitive to useless, depending on the source and duration.
See Access to learn more about wind site analysis. Meanwhile, remember that knowing the average wind speed on your site is crucial to predicting wind-generator energy production. And small differences in the wind speed can make a big difference in production. For instance, the energy available in a 12 mph wind is about 70% greater than the energy available in a 10 mph wind.