Thorium reactors [0], Lightsail tech [1], and vertical helix-shaped wind turbines, throw in some Stirling Engine action [2].

Why aren't we past all this yet? Oh, right, politics.

  [0] https://en.wikipedia.org/wiki/Liquid_fluoride_thorium_reactor
  [1] http://www.lightsail.com/
  [2] http://science.howstuffworks.com/environmental/green-tech/remediation/slingshot-water-purifier2.htm