Nuclear fusion will, in the near (50~100 years possibly) future, be the answer to all of humanity’s issues on energy sources.
BUT, we aren’t even that close to controlling any kind of nuclear fusion yet, let alone do it everyday and everywhere to produce energy.
But when we do, yeah, you can kiss your thermal plants and your oil goodbye. Ridiculously high amounts of energy with no environmental drawbacks? Do want.
By the way, the most obvious way of using Nuclear Fusion to generate energy would be to fuse Hydrogen atoms into Helium, not fusing Helium-3 atoms into… I don’t know… Carbon? Whatever.
That’s the way stars do it, and it has worked out pretty well so far.