Unless I start seeing citations, that is unverified opinions and/or ideas; and Geodude was already disproven completely. xD
How about how electric Pokemon get the energy? Or have you all done that one?
Chinchou Pokedex entry (Emerald): Chinchou's two antennas are filled with cells that generate strong electricity. This Pokémon's cells create so much electrical power, it even makes itself tingle slightly.
Pikachu Pokedex entry (Emerald): It stores electricity in the electric sacs on its cheeks. When it releases pent-up energy in a burst, the electric power is equal to a lightning bolt.
Both Pokemon (including their predecessors and successors in evolution) appear to have
electrocytes.
Now, something like Magnemite? Well...
Silver entry: The units at the sides of its body generate anti-gravity energy to keep it aloft in the air.
Crystal entry: The electricity emitted by the units on each side of its body cause it to become a strong magnet.
Fire Red enrty: It moves while constantly hovering. It discharges Thunder Wave and so on from the units at its sides.
It's not clear how, but its magnets have a double job of both keeping it aloft and discharging electricity.
Everyone would do good to check all their question Pokemons' Pokedex entries (I know Bulbapedia has them on their Pokemon pages) before posting here, you may find your answer.