Unfortunately it's fairly difficult to come up with good numbers to compare alternative energy, as there is an incredible amount of hype and emotional attachment for and against it, at least on a broad-brush level, ie trying to decide if coal or wind is "better," etc. You have the hippie camp that is more likely to say damn the cost, it's good for the environment, and anti-hippie camp that says all this frou-frou stuff is a waste of money, and even another hippie camp (I like to think of them as the more Amish hippies in that they are anti-development) that claims the spinning blades are killing bats, etc. Everyone who has done any published research has a bias towards one side or the other, and naturally these published results contradict each other quite a bit.
As a further example of the illogical thought processes normally dedicated to deciding whether or not wind energy is "good," just the other day someone told me that wind turbines are bad because after the big motors in the top spin the blades up, they only make 15% more energy than they consume. First off, anyone who claims they use motors to "spin up" the turbines should probably just keep their mouth shut. The big turbines do have pitch and yaw control motors, but I have a hard time believing they consume that much energy relative to the output, at least over a long period of time. But even if that were the case, you're still producing electricity, and if the fixed costs and operating costs of the turbine are less than the value of the electricity it produces over its life cycle, you are still coming out ahead.
Fortunately at the individual level at least you can look at average wind speeds in a given area, output of a specific turbine, purchase cost, installation cost, estimated life, maintenance costs, etc., and plug those into Kyle's metric and determine if it's "good."
I'm not sure about the rest of the country, but there has been probably a 20 fold increase in the amount of wind farms in Iowa in the last 5 years. And while I'm sure they are probably getting some sort of federal subsidy, for them to put up that many would sure seem to indicate that there is some economic benefit to them as a source of energy. I don't believe the world has gone that crazy just yet. If the growth was solely based on subsidies it would probably be more comparable to the growth of ethanol IMO. But of course these are all owned by the power company, and I don't know that much about growth in privately-owned wind turbines, other than they are available. So to take a look at that, let's go back to more "broad brush" inherent issues with wind energy: As everyone knows, wind energy only works when the wind is blowing. So if your electrical demands aren't in sync with the wind, and it's your primary source of electricity, you're going to need storage, hence the requirements for better batteries as has been mentioned here earlier. On a grid, they basically just "use less coal" when wind output is high. On the other hand, wind is unattractive for grid power due to the cost of transmission; areas with high wind are not necessarily the areas with a lot of electrical demand, so transmission distance is often much higher.
In terms of electrical output, output increases with the length of the blade and height of the tower, which is why there weren't too many popping up until they started making these huge ones. Basically they had to reach a break-even point where the towers became tall enough they could get the output high enough to get a solid net positive. The constraints with making taller towers are, interestingly enough, largely limited by how big of a blade they can get down the highway from where the blade is manufactured to where the turbine is going. Another factor is how to make such large blades cost effectively, which are often made of fiberglass. The foundation is also important, as a very large turbine will have a large drag force at a large height, resulting in a VERY LARGE overturning torque.
So I guess my bottom line is that wind energy, in some applications at least, appears to be an economically sound source of alternative energy, and in some cases the only practical solution for an individual (at least until someone comes out with a "coal plant in a box" for under $50,000 or so
). For an individual, storage is most likely an important issue. Net output/efficiency increases with turbine size, so smaller turbines like those sold to individuals may not be as much of a "big winner" as the larger ones the power company uses. But I'm pretty sure my friend Jim in the link above probably ran the cost analysis on it, he's pretty level-headed. Not sure what value he placed on the "dollar value of self reliance" though
For those fortunate enough to have a creek running through their property, this may be of interest, it's a company started in Afghanistan a few years ago by an American engineer that used to work for John Deere:
http://www.remotehydrolight.com/Afghanistan costs (ie somewhat normal rates for material, but labor was $5-10 per DAY) were in the ballpark of $1,000 per kilowatt, with powerheads available that put out in the ballpark of 1-120 kW. With a 10-15 foot column height of water on a stream maybe 3 ft. wide and 12" deep I'm thinking you could produce like up to 60 kW. And it would be a lot more regular/reliable source than wind.
