Ars Technica has a great summary of the current state of the art in wind turbine technology:
As a result, enough wind power has been installed in the US to avoid 115 billion tonnes of carbon emissions in 2013 alone.
Despite that progress, wind currently accounts for less than five percent of the total electricity generated in the US. That stands in stark contrast with the total potential for wind power, which is more than 10 times our current electrical consumption.
We aren't taking full advantage of this for several reasons. It's partly a matter of manufacturing capacity; wind has only been booming for about a decade, and it takes time for companies to respond to that demand. But two interrelated factors have also slowed wind's adoption. Many of the best areas of the US for wind power are in the most sparsely populated states, far from the high-capacity transmission grids that support more populous regions. And many of the most populous regions have wind resources that we simply can't harvest economically at the moment.