Get Off the Grid with Wind Power

Catch the show ECO-TECH on the Science channel, episode Powering Up.  There's a discussion about fan blades in the shape of the DNA helix to prevent high speed rippage especially in cities like Chicago.

Without agreeing or disagreeing I would like to point out that with any renewable energy device designed to harvest the energy of motion in nature and convert it into electric energy, geographical location and local terrain as well as ambient weather conditions can all have an effect on power production. Which in turns has an effect on cost effectiveness concerning the RE device. This doesn't rule out desire of course. Just common sense. If you live nextdoor to a large body of water with a high drop in elevation but you just got to have a windgenny, then by all means indulge, but if your looking to "squeeze" the most RE out of your Ben Franklin's then be very critical of your personal site evaluation.

Its been printed that a general "rule of thumb" for windgenny's is that the bottom of the swept area of the blades should be no less than 30 foot higher than any object within a 500 foot radius.
 This is because those objects within 500 foot create turbulent air, which reduces power output, as opposed to a more consistant smooth flow of air, that creates higher power output.
 Then you have to sept outside that "circle" and look at local terrain at a half mile as well as the trees. It would help to have an elevation map for this evaluation.
 As an example, where I live the trees are in the 75 foot range in my yard. So right there, that means a tower no less than 115 foot, but at the same time we live on "bottom land" where at one quarter mile radius the terrain goes up in elevation anywhere from 25 to 50 foot with those same 75 foot trees.
If that wasn't enough, when I look at the national data for average wind speed for the region of the U.S. where I live, we are in the 0 percentile on a scale of 0 to 7 (7 being best) and this stretches over three states.

When I add all of this up into dollars and cents I would have bought a very expensive tower to support a windgenny that will only produce an appreciable amount of power when there is a windy storm. The majority of the year it would just sit there, like one of those concrete yard Gnomes. You know, the one hunched over with the sheepish grin on its face.
Unless you have "money to burn" I would suggest being very critical of your site evaluation before purchasing any RE.