About 22+D, simply said string theory will enable us to take energy from parallel universe(string theory - theory of multiverse, if i'm right), which will, accordingly to Sci-Fi, make a rift in their space-time and possibly destroy it with exotic particles which behave out of regular laws of physics.


On the one extreme "free" unlimited energy creates massive problems with overheating. - Clarke

It is understood that there is not something as "free" energy, especially unlimited, it's only a question how much effort do we need to invest to get that power...the bigger difference is, the better power source is.

That is right, source about that, as he can produces energy more then we can imagine so he can overheat and overcharge beyond that.
(and in that case we are talking about explosion that will go beyond of explosion because of meteor in diameter >2km)

Aaaand, after last sentence i think we don't need that kind of power source.
Go green...