Powering a TARDIS

Hello again! As stated in my earlier blog post, the TARDIS has only a limited internal buffer of artron energy when seperated from the prime Eye of Harmony. So, the question: How is the TARDIS functioning OUTSIDE our universe??? (i.e. in equestria and such) The main problem presented is that the TARDIS is finicky when scavenging for fuel, and only accepts energy from the Doctor's home universe, so theoretically it should not remain functional in parallel/alternate universes.

There are a few logical reasons I have thought of or have been presented in various crossover fics.
1. This is that universe's version of the doctor, so no problem.
2. The TARDIS has adapted to absorb energy from the universe the doctor has been flung into
3. In a more specific context (MLP universe), The TARDIS can substitute magic as an alternative fuel source (from Loyal2Luna's fic series)
4. This universe's version of Galliferey has not been "destroyed" by the doctor, so the TARDIS is tuned to this universe's Prime Eye of Harmony. (Hmm, could make good fic content)
5. Magic IS artron energy, so TARDIS is easily refueled. (Unsure which fic this one came from, will add a name if I can find it)
There are still other ways to keep the TARDIS fueled, so be creative! This is not the be-all, end-all list of them.

Toodles!
~Ninja35