[[quoteright:221:[[Franchise/GreenLantern http://static.tvtropes.org/pmwiki/pub/images/PowerBattery.jpeg]]]]
[[caption-width-right:221:Hal's just happy the battery has no summer or winter rate hikes.]]

->''"We need more power, Cap'n!"''
-->-- '''Scotty''', ''Series/StarTrekTheOriginalSeries''

SpeculativeFiction and {{Fantasy}} have a great many devices, vessels, abilities, and powers, and they have to run on ''something!'' That is what this trope is about. Be it {{Phlebotinum}}, [[StarTrek Dilithium Crystals]], {{Mana}}, or [[{{Popeye}} spinach]], there are many and varied Power Sources for a story's fantastic features to run on.

Power Sources have two basic characteristics: Nature (natural, scientific, magical; neutral, good, evil) and Replenishment (infinite, automatic, harvested, finite). In terms of Replenishment, some power sources are naturally replenishing and perhaps limited only to "needing an hour to cool off" or a good night's sleep. Others need to be harvested in some way, be it a vampire feeding off humans or a robot plugging into a wall. Other power sources are "[[PerpetualMotionMonster always full]]," or "infinite", so a hero or starship never has to worry about refueling. This can remove a source of plot complications, and may seem a bit [[PVPBalanced unfair]] when others get their PowerAtAPrice. Thusly, these tend to get stolen or short circuited. A lot.

In terms of Nature, the sky is the limit. Two heroes with exactly the same power can fuel it with different things, or some can use exactly the same Power Source for two radically different powers. For an especially interesting dynamic, a hero and villain may be powered by mutually weakening energies, for example one using ThePowerOfLove to fight a [[TheDarkSide Hate Fueled]] foe.

This and HowToGiveACharacterSuperpowers overlap when without the Power Source the character has no powers... it's not the character needing the Power Source to fuel the powers, but the Power Source that also imparts the powers.

Here are some sample Power Sources.

!!Magical power sources include:
* LifeEnergy - their own [[LiquidAssets or another's.]]
* [[EmotionEater Emotions]]
* {{Mana}}
* [[ThePowerOfBlood Blood]]

!!Science power sources can be:
* {{Phlebotinum}}
** PsychoSerum
** SuperSerum
** ToxicPhlebotinum
* [[LightningCanDoAnything Plain old Electricity]]
* [[ILoveNuclearPower Plutonium (or any nuclear/radioactive material)]]
* [[ThePowerOfTheSun The Sun]] -- either as photo voltaic energy or as a mystical entity.
* PureEnergy.

!!Artificial power sources are usually:
* {{Amplifier Artifact}}s that supply the SuperMode
* {{Power Crystal}}s

!!Mundane power sources can be:
* Food -- They not only have a HyperactiveMetabolism, but need food for the energy to use their powers.
** PowerUpFood - Eating or drinking a certain food provides powers.
* Stamina -- The hero can use their powers with no real "fuel" limitations, only being limited by natural well being and endurance.
** HamsterWheelPower is the comedy version of this variant.
* Gasoline -- Or wood, there ''are'' steam punk suits of PowerArmor.

!!Morality Neutral, Good, and Evil power sources may include:
* {{Aesoptinum}}
* TheDarkSide
* TheLifestream
* PoweredByAForsakenChild
* ThePowerOfFriendship
* ThePowerOfLove
* DealWithTheDevil
* LivingBattery

!!Some sample Replenishment for Powers Sources:
* HourOfPower
* FuelMeterOfPower
* ManaMeter
* PhlebotinumBattery
* PowerIncontinence -- Always On, oh, are they ''ever'' "Always on!"