[Troubadour]

Originally Posted by zilfondel

Except that you can only get up to a Type 2 civilization by using solar. To go any higher, you need Fusion!!!

http://en.wikipedia.org/wiki/Kardashev_scale

It'll be on order of 100k to 1M years before we're a Type II civilization, and spreading to other stars and having fusion power will occur long before that. Artificial fusion will never, ever be cheaper than just passively soaking up the energy of a star - it's main applications will be in the outer solar system and interstellar travel. The point is we today can't even imagine the vastness of the journey we are embarking on today with solar energy. It changes everything.

BTW, historical trends have us reaching Type I status some time around 2230. Of course, that ignores the exponential growth potential of photovoltaics.