It all revolves around nat gas.
The nat gas shortages in 2001 and 2002(remember Enron) set off the first wave of windmill building. Then the Katrina related nat gas shortages set off the second wave.
Now we have excess nat gas, but when we start exporting nat gas the price goes up so wind, coal, & nukes become more profitable
(You are correct about the effects of exports on NG prices)