I don't know that it will be fusion but I think eventually we will solve the energy problem. If we look at nature the energy scale of natural processes such as

I don't know that it will be fusion but I think eventually we will solve the energy problem. If we look at nature the energy scale of natural processes such as solar flares, movement of planets, oceans and atmospheres, etc dwarf human needs. The energy is out there we just haven't figured out how to efficiently access it. When we look at atomic processes the conversion of even tiny amounts of mass to energy also easily dwarf human needs. I know we are constrained by the First and Second laws of Thermodynamics but I think this is powerful evidence that there has to be a way. Both fusion and fission convert mass to energy but are crude ways to do it. Physics is currently stuck and has been for 60-70 years. Physicists cannot integrate the large scale theory (General Relativity) with the small scale theory (Quantum Mechanics). They are incompatible. I can't prove it but I suspect that once this impasse is resolved we will find elegant ways to convert mass to energy and the energy problem will be solved.