différence between AC and DC

[ohm77]

Hi everybody,
Could you give me an answer for this question: Why direct current (DC) can be stored but alternating current(AC) can not be?
thank you

 

[Prototyp_V1.0]

Of course you can store AC. Ever heard about Pumped-storage hydroelectricity.
A rotating phase compensator also do store energy as AC.

 

[BradtheRad]

AC needs to be generated on the spot.

If the AC is to continue being AC, then it needs to be stored in the form of something rotating, or swinging, or oscillating, etc.

The closest thing to storing AC is an LC tank loop made from a coil and capacitor. It can be made to oscillate on its own with no input of energy, for a while. Eventually it decays. At a temperature of absolute zero, it might go on for a much longer time.

If a magnetic field could be made to self-sustain in an oscillating form, that would be sort of like storing AC, except it would be a case of converting it, not storing it directly. I've never heard of a self-sustaining magnetic field, however.

A generator in conjunction with a flywheel or spring might be similar to storing AC, but that will decay.