I have several thoughts in response here.
1. Look at the reasons why wind and solar have seen increased adoption in recent years. I think you'll see two key factors. First we see increasing tax benefits and subsidies for clean energy. Second, you'll see a lot of this activity kicked off around '06 or '07, when natural gas and oil prices were soaring to record highs. Both of these are clear indications that wind and solar still struggle to be economic, even at the margins.
2. Keep in mind TFA is not talking about on a US only scale, but a global one. Increases in wind capacity in the US are completely dwarfed by the number or coal plants being brought online in China on a nearly weekly basis. In terms of green / fossil fuel ratio, I think we're more likely to be actually moving backwards on a global scale.
I'm not opposed to clean energy. But the authors of TFA article have their head in the clouds.