>>14412012great explanation. I'll add for fusion, from my perspective as an engineer, fusion happens when you heat some gas by an unreasonable amount, after which occasionally two of the particles whizzing around inside will smack into each other, producing some new particles. Overall the new particles have more energy than the two original particles had, which is sorta bullshit. But it's why the sun shines, so we can't complain.
The idea is this happens often enough that the gas (well, now it's plasma) produces more heat than was put in ("breakeven"), which is tough. It's tough because the gas is always cooling down for various reasons - some of it is particles leaving ("transport" is the name, I think?), some of it is particles' electric fields slowing each other down ("Bremsstrahlung").
When it happens so much that the power plant overall produces more electricity than was put in ("economic breakeven"), you make a shitload of money, people start sucking your dick everywhere you go, and you still don't have a gf.
