Superman's powers rely on his cells' ability to absorb and metabolize solar energy from local stars like Earth's sun. His Kryptonian body is a living "solar battery" that absorbs solar energies and converts them for fuel for his powers. His cells also store yellow sun energy so he can use his powers under objects, at night, in dark places, and in space.

The more yellow sun rays Superman absorbs the stronger he gets; in some instances he has been shown to enter the sun in order to increase his powers to their highest potentials.

Superman can also absorb solar energies of other class stars such as when he absorbed the solar energies of a blue star that increased his abilities to a higher degree and gave him additional abilities. Being under a red sun completely diminishes Superman's powers and abilities.