"Look at fusion."

Precisely. We look at it every time the sun rises. Giving us all the power we need, one way and another - wind power, wave power, tidal power, fossil fuels, it's all solar power when you get down to it. And we are only using a tiny fraction of what's there - and it's good for another 5 billion years or so.

Maybe someday we'll have the technology to run fusion on a smaller scale locally, here on Earth - but as of now we can't, and it's no good assuming we'll be able to do it. Counting your chickens before the eggs are even laid has always been considered to be a dodgy basis for forward planning.