All Energy is Atomic Energy
In "E=mc2" I showed you that the chemical energy in 6000 gallons of gasoline is equal to the atomic energy in a tiny drop of water. To extract the atomic energy, I would have to annihilate the drop of water, converting all its mass to energy.
What if you burned 6000 gallons of gasoline and measured the weight of the products of combustion? Would it surprise you to learn the products of combustion weigh less than the gasoline by exactly 1/225,000th of a pound -- the same as the weight of the drop of water! That's where the energy comes from, you see: the missing mass.
Thus all energy is atomic energy.
Did your universe just get simpler? That's the goal of the belief system we call science.