This is an interesting article, but installed capacity is not the most relevant measure of wind power penetration. I would find it much more interesting to read an article in this format that ranked sources by (KWH/whatever) that was delivered to the grid. This seems to me to be the only measure that tells us what the relative penetration of renewable sources really is. Many renewable sources are intermittent, especially solar and wind, so that the nameplate installed capacity, which I presume are the numbers the author was using, do not tell us much.
Also, an article dealing with the ratio of average kilowatts generated divided by the nameplate power rating for wind and maybe solar, listed by state or wind farm, would be quite interesting. I have been a fan of wind for years, but don't want it to be oversold.