Steady wins the race. I remember a few years ago when pundits said: "Wind power is barely 1% of US electricity, how can it make a difference?" Well, since then, wind power has fallen in price -- since 2009, the price of wind turbines has fallen by about 1/3 -- and big investments have increased total wind power generation almost five-fold! A few more doublings and we're talking a serious chunk of the U.S. demand, which, when combined with solar power, which is also on a tear, really changes the energy game.
In January 2014, wind power generated 4.8% of America’s electricity. This breaks the previous January record which had been set in 2013, which in turn had broken the 2012 record, and so on. If you compare any period to the previous period in a seasonally adjusted way, because the wind doesn't blow as much during the summer, you get one all-time-high after the other, which is always a good sign.
The exciting thing is that most of that growth happened when wind power was still more expensive than coal and natural gas without subsidies, but we're reaching the point where that's no longer the case. At around $84 per megawatt hour, onshore wind power now costs the same as gas worldwide. Depending on how windy an area is, it can be cheaper than coal and gas.
Here's the sites of US onshore wind farms from 2012 (there are more since then, but they tend to cluster in the same high-wind areas):
And yet the U.S. is still not quite a leader in wind. This graph (though from 2012, so things have changed a bit) shows how Denmark, Portugal and Spain area leaders in wind power, at least as a percentage of their electricity consumption: