On Tue, 26 Aug 2008 23:02:38 +0100, John Weston
wrote:

Whatever little you are getting now, you'll get very little extra with
the larger turbine blade diameter.

Output varies with the square of the diameter. Three times as much is
what you get with the larger unit. To digress a bit the state of Iowa
gets five percent on its juice from wind, compared to one per cent
nationally. The common 2 MW 150 foot rotor ones would equal a thirty
barrel a day oil well. That is if the wind always blew. Chicago has
the nerve to call itself the windy city, but Des Moines is windier.

Casady