Looking ahead, there may be a better alternative to the basic theme... First, it ought to be easy to test the basic concept - which is a series of rotating wing-like airfoils - without going to the enormous expense of a jet steam version.
Imagine a gigantic light-weight "Ferris wheel" built using kevlar spokes with a thin rim of kevlar and with the airfoils attached to that rim. The airfoils would be individually controlled in their "attack angle", using computers to maximize the "lift" which is converted into torgue very efficiently by the large rotating mass. Each airfoil might be several hundred feet in wingspan - they are essentially the wings of glider aircraft, and might be mass produced as such. The whole device is mounted on a turn-table, in order to always face directly into the wind. The wheel is sited on top of a mountain with reliable wind. This concept might end-up producing more kwh per invested $dollar of cost than the traditional array of hundreds of individual mills. The reason that the idea looks economically feasible, on first appraisal, is this: In a traditional mill, most of the weight is in the stationary tower and provides no real energy. Here the supporting structure itself turns and provides torque, so there is less "dead-weight". Using one large generator, instead of hundreds of small ones also should be economically advantageous, in both capital-cost and efficiency. Also a wing, rather than a propeller is mounted so that its leading edge is more perpendicular to airflow, and this uniformity has advantages in lighter weight. Of course, kevlar is more expensive than steel in 2005, but kevlar is essentially carbon, so the actual cost, in a longer-term perspective, has a lot of downside potential - if the demand for it increases to a tonnage level closer to that of steel. This could be the "killer-ap" which increases the demand for kevlar (and/or normal graphite fiber)to the level where cost falls very quickly. Jones
