One thing that's always important to keep in mind is that, as technological development goes, wind power, solar power, geothermal, and all the rest are still in a growth stage. They haven't had decades of industrial investment like coal and natural gas. So, expect to keep seeing articles like this one, about a turbine blade design that's more efficient at harnessing low-wind speeds. The more diversity we get in terms of dealing with different wind speeds, the more evenly we'll be able to spread wind farms, which means less concentration in particular regions and less loss due to transmission. It also makes us better able to take advantage of the continual availability of wind somewhere.
So, keep it in mind: wind is getting more efficient (and already some studies put it as generating up to 50 kWh for every one kWh of fossil fuel input), while coal is mired where it's always been: about 30% efficient (i.e., 1 kWh of electricity for every 3 kWh fossil fuel input).
ALSO: Years ago, I heard that one of the big problems facing wind turbines was bugs. Just like bugs splat against your windshield on the highway, bugs splat against turbine blades, which--after enough time--degrades their performance. Does anyone know if this is still an issue? It seems like a straightforward maintenance fix, but maybe nothing is straightforward on a tower 250 feet in the air.