Brief Calculations on Small Wind

I just got off the phone with a gentleman who is representing a solution in small vertical axis wind turbines (HAWTs). He claims that they produce 310 watts per square foot.  Using this handy wind calculator, we find that this would require a steady breeze of 54.1 mph, which exists nowhere on this planet.

Another claim: 11 MW per acre (compared with the big horizontal axis wind turbines that represent virtually 100% of the wind power today, which he says require 15 – 20 acres apiece and produce perhaps 3- 4 MW).

OK, imagine wind blowing across an acre of land, 207 feet on each side, running into a row of 8 foot tall HAWTs, so the cross-section is 1659 square feet.  Once again pulling up our wind calculator, we find that producing 11 MW requires a wind speed of 149.2 mph. That sounds like a real problem to me.