A report from the Chinese government asserts that solar power will be as cheap as coal by 2015. Industry watchers have already predicted that the cost of solar will drop by half by 2020, putting it at parity with coal-fired power. And solar is already competitive on sunny days when utilities pay a premium for "peak" power.
But what's it all mean? Revolution, baby. "Grid parity" — the point at which the choice between fossil fuels and renewables is a shrug and a coin toss — has been the Holy Grail of this industry ever since Jimmy Carter asked America to put on a sweater in order to protect everyone else from the lust in its heart. All other things being equal, grid parity is the point at which all our new electricity production infrastructure switches from dead dinosaur juice to sunbeams and breezes.
Of course, even at grid parity, all other things will most certainly not be equal. We'll still have to contend with the intermittency of renewables, and that's a whole other cost structure to work out. But still!