Sheerwind
Okay so it starts with normal wind at as little as 2mph (influx) and then with series of venturi tubes and processes the wind is sped up to 45 miles per hour. Then the blast is shoved through a turbine generating electricity and an exit wind at 15 miles per hour (efflux). All right.<p>So why not take this efflux wind at 15mph back to the top again, or even half way with some loss of course, and achieve a perpetual motion machine [1]?<p>Is something missing in the introduction video about this concept?<p>[1] <a href="http://en.wikipedia.org/wiki/Perpetual_motion" rel="nofollow">http://en.wikipedia.org/wiki/Perpetual_motion</a><p>[Okay got it: The blade area/size of a fan to turn at winds as low as 2mph is quite high (and expensive) as compared to rotor blade size that would work with winds at speed 45 miles per hour. This one looks like a play on lever action of wind on fan blade area/angle w.r.t achievable influx velocity. Not too bad it's a kind of optimization, but for the introduction video that wasn't clear enough.]