Politics aside, I wonder how this thing works...
From some close-up photos and the descriptions on the maker's Web site, I figure the basic design is the following. The turbine blade tips are joined to a ring. This ring rotates inside the prominent shroud that we see. Mounted on the ring are permanent magnets, which move past fixed coils mounted on the shroud. Motion of the magnets past the coils induce a voltage on the latter.
At low speeds, the only drag on the rotor is its center hub bearing. Hence, the turbine can spin with very low wind speeds. At higher speeds, as one extracts power from the coils, the induced currents in the latter produce a magnetic field that acts as a drag force to slow the rotor down (How does one extract energy from a moving object without slowing it down?). At very low speeds, there is no power produced however, and the turbine can move very freely with little wind.
Compared this to the conventional air generator that requires 7mph wind to startup due to friction of the gear and the generator, this new design probably can generate power with winds of only a few mph. It also has a lot more blades than the traditional 2 or 3-blade design of small wind generators of this size. This obviously enhances its ability to produce power at low speeds.
But where is the windspeed-to-power chart or curve?
I have a few questions to ponder. First, how tight a magnetic coupling can they have between the magnets and the coils? It seems to me it is difficult to make it as strong as the magnetic coupling between the field coils and the armature of the conventional rotary motor/generator. This may limit the efficiency in converting mechanical power to electrical power at higher wind speeds.
Secondly, if my hypothesis is correct of the mechanical design of the rotor, this turbine has a much higher moment of inertia than the conventional wind generator. At high winds, the typical generator is designed to "side-furl" to the wind. This turbine uses an active control system to turn it sideways to the wind. I wonder how fast it can be turned to respond to wind gusts.
Anyway, for a time, I did entertain the idea of living off the grid in my 2nd home. So, I looked into something like this. It is about the same as the Skystream posted by Tomcat.
Whisper 500 Wind Turbine - Southwest Windpower
This Whisper 500 with a 15ft diameter rotor produces 538 kWh/mo at 12 mph. That's $1000/yr at $0.15/KWh. At 24 mph, it generates 3KW, or 26280KWh/yr, or $3900/yr. At the cost of $7K, the payback is short and sweet at only 2 years. Of course, I would need to use all that power, or have access to a grid so I can pump it in and get paid for it.
Now, where can I find a place with 24mph wind 24hr/day? Well, you would not want to live on such wuthering heights. So, that wind must be at some height above the ground, hence these generators are usually mounted on poles. Depending on the location, location, and location, I believe these things can work and be economically feasible if mounted high in the wind. I have reservations about the low-speed turbine, however.