[Ryland]

I don't think it's increasing the frontal area of the blade swing area,
but it's using the wing lift principle to generate low pressure behind the blades.

No, you are not increasing the blade swing, you are increasing the collection area, by increasing the pressure at the front and decreasing the pressure behind and while it's not increasing the blade swing, it is increasing the frontal area, thus increasing the area that wind is being collected from.
Any time you keep the air from spilling over the tips of the blades you are going to increase the output, you can do this with a stationary rim, or you can do this with winglets on the tips of the blades.

Originally Posted by Big Al

Is wind power cheaper ? In the Uk and probably elsewhere it receives huge subsidies so comparing lifetime prices is difficult.

The 4 to 7 year pay back I mentioned is before any subsidies, there are alot of wind farms that have been put up without any tax dollars and they are making a profit, one such wind farm is in Oregon on the coast and is creating enough power and paying enough in taxes that they are creating a tax surplus.
There are a lot of other examples of schools (because they often have a large enough chunk of land) putting up wind turbines to at first off set their electrical use but are finding that they are seeing a positive cash flow.
Also, when there are subsidies, they are in the form of rebates to help offset the costs of installing, to make it a more appealing long term investment because it's going to have a quicker pay back, but if it's managed you will also have a long term sustained pay back because it will be like buying an oil well that doesn't run dry, but even oil wells need to be maintained.

One thing is for sure as commercial wind turbines of the Hawt design get bigger the cost per unit of electricity generated goes up !!

Where are you getting this from? if you look at the installed cost and the output, the large you go the cheaper the electricity gets and the quicker your pay back is, the only time that it's practical to put up smaller turbines is if there are restrictions on size that is allowed in an area, an example of this is my parents property is a great wind site, not the best of course, but pretty good for our area, but unless they want to get in to all of the permitting that you have to do with industrial sized wind and the zoning restrictions and the fact that our Governor is corrupt and added restrictions that nearly ban industrial sized wind turbine in most of the state, they are restricted from putting up anything over 15kw in size, but I'm pretty sure they could put up 10 15kw wind turbines.

Also wind power can never do more than provide a top end power over a nuclear or fossil fuel base load. I don't think that we'd accept as base load a generating system that produces nothing on the many, many calm ( or very stormy days.

A wind site is not going to have good pay back if it does not have consistent wind and the wind is predictable enough in a lot of these sites that projected power outputs are withing 3 to 5% of real life outputs and the nice thing about wind is that when it is used in conjunction with coal or other existing power plants, those power plants can be dialed in to run at their cleanest and most efficiently and the wind turbines can be throttled back as needed without polluting extra like coal does when you throttle it back, often times if you see a wind turbine that is not spinning that is the reason, throttle a coal plant back and the cost per kwh goes up and the pollution goes up, throttle back a wind turbine and nothing bad happens.

And yes, there are failed wind farm, often times they were run by greed, to keep a wind turbine running for 100+ years you need to budget 1% of the installed cost per year for maintenance, if you don't and you put all of the profits in the pockets of the greedy then 10 years down the line when something needs to be repaired there is no money to do it and you get some perfect propaganda photos of dilapidated wind turbines.
Thing is, if you don't budget for maintenance in any other kind of power plant you end up with the same issues, only we don't see it, we just taste it in our polluted ground water.