There are really only four types of energy: Solar, nuclear, geothermal, and gravitational. Every other source of energy we know of - fossil fuels, switchgrass, wind, waves, and so on - is based on one of those four.

Let's skip the middleman of fossil fuels and wind and get our energy straight from the sun.

(I'll even go so far as to suggest that the sun is really nuclear, and gravitational depends on the initial energy of something blasting the Moon out of the Earth's crust... so, I'll refine my list to two types of energy: nuclear and galaxial. And, yes, these both can be factored into "physics," but let's stay practical, people!)