Re: Renewable the only long term option
ok... admittedly some of this is sourced from wikipedia (so take it with a pinch of "bloke down the pub said"), the earth's inventory of nuclear fuel is supposedly worth 2.5 YJ of energy, that's 2.5 x 10^24 J. Which if I've got my maths right is ~700 million TWh; or at a rate of 5000TWh/year is 138 thousand years worth. I think we can consume it a tad faster than that. ;-)
NB: Thorium is much more abundant than Uranium, and could (again *supposedly*, it's a wiki fact) last hundreds of years (or more). Giving plenty of time to sort out fusion.
Then there's geothermal. That isn't sun derived either. This is already producing 67TWh every year, and that's just the low hanging fruit (like Iceland and the other hot spots).
I'm willing to concede that even geothermal & nuclear are at least partially "sun derived" if you count the supernova that formed all the nuclei heavier than Iron in the first place, and geothermal heat is a mixture radioactive decay heat from early in the earth's history and gravitational potential converted to heat from the earth's formation.