My problem with all of this is that, as renewables get cheaper, people use less fossil fuels. But this drives the price of fossil fuels down. Eventually all you're extracting is the low-hanging fruit that can be pulled out of the ground very cheaply and running tight margins on it. So you have kind of a vicious cycle. Meanwhile most people just assume that fossil fuel prices will increase inexorably. I doubt it.

In other words, absent regulation keeping fossil fuel costs high (carbon tax!), I think the shift to renewables will take longer than the optimists think.