The world needs a new source of energy, an unspillable source.

When electricity is generated, where do the electrons come from?

I know that in a generator powered by a steam, water, or wind turbine or whatever turns a magnet which is surrounded by a very long wire. The magnet pushes or accelerates the electrons in the wire to produce an electric current.

I know that if these electrons aren’t being continuously replenished, then the wire will eventually run out of electrons. My question really is, since we know the wire never runs out, where do these electrons in the wire keep coming from?
I have recieved good answers here telling me that the electrons just return to the wire from the electric grid. It is kind of like wastewater returning to the treatment plant from somone’s house.

I still wonder, what about gasoline generators that might be plugged into a lamp, but are not connected to anything else?