Noah Smith, a finance professor who has studied both physics and economics, has an interesting blog post that argues that solar power is on the cusp of truly becoming much cheaper. It's about to become a breakthrough technology that will have transformational effects, he says. (Debate is lively in the comments, but at the end of the day I think he makes a pretty good case.)
Hat tip, the invaluable Tyler Cowen on Twitter.
Smith is silent on whether cheaper solar technology (and the efforts of companies such as SpaceX to make putting cargo in space cheaper) would revive the notion of space-based solar power, as promoted by Robert Anton Wilson in the Schroedinger's Cat trilogy. I posted a question about that in the comments and will update if I manage to coax a reply from Professor Smith.
UPDATE: No response from Professor Smith, but "Brett" in the comments argues that space based solar is not economically feasible: "It would have to lower the price of cargo to orbit a lot, as in several orders of magnitude. I don't think that's going to happen.
"The costs of not just launching the panels into orbit, but also assembling the array, maintaining it, and replacing panels when they stop would be exorbitant. You could probably build a fair amount of ground-based power plants for the cost of one space-solar array, and it would be vastly easier to maintain the ground ones.
"It's the same type of reason that the US and other powers with nuclear weapons and launch capabilities didn't try putting them in orbit (treaty aside). The launch and maintenance costs are staggering."