Which energy production method does not ultimately depend on the sun?

Nuclear fission. This is because the source comes from a mineral. All other forms of energy rely on the sun. Wind is produced by the turbulence of the air from the uneven temperatures in the air caused by the sun. Coal is derived from organic matter which at one point must have come from organisms that have lived that have relied on the sun as a form of energy because at the lowest trophic level there must be photosynthetic organism. Solar energy requires the sun to be out on the photoelectric cell in order to function.