Actually spend the "Green" on a Skystream 3.7. Most it produced is a little over 3183 kWh to date; over a three plus year period. My wind speed dropped by 2 MPH, my electricity delivery company keeps the voltage to high, according to Southwest Windpower. (The things one learns, the higher you go the slower the wind blows, must be the thin air.)
They were super and replaced the original turbine twice even added a "Skylevel" free of charge that did not work and does not come with a warranty since the original equipment did not have one. Sure hoped that this Skystream 3.7 would help out with the environment, keep jobs here..., actually it does. Noticed some birds resting 50' up on the turbine.