> It’s a bounded sink for electrons, though — i.e. it has capacitance — insofar as a positive ionization required for a static discharge (lightning) built up in the earth can be “spent” by grounding voltage into it.
The Earth has no special ability to absorb electrons beyond what a jar of dirt does.
In a lightning discharge, the earth and the thundercloud act as opposite plates of a capacitor with an air dielectric.
As a thought experiment: if I built a hypothetically perfect giant metal shield covering the entire planet 100ft above ground, and perfectly insulated it from earth, lightning would discharge to the shield, and there would be zero potential from the shield to the actual Earth either before or after the discharge. There is nothing electrically special about the physical Earth, it's just a conductor.
> Ignoring that, though, what people usually mean by this is that the combined neutrals of the entire power grid are on the other end of any dumping of current you’re doing into ground.
What you're describing only happens during fault conditions.
Except in extremely unusual circumstances like [1], the Earth is not used as a normal return path for utility neutral current. The return current flows on dedicated neutral conductors. Actually, in am ideally balanced Wye, there isn't any real neutral current at all.
The Earth has no special ability to absorb electrons beyond what a jar of dirt does.
In a lightning discharge, the earth and the thundercloud act as opposite plates of a capacitor with an air dielectric.
As a thought experiment: if I built a hypothetically perfect giant metal shield covering the entire planet 100ft above ground, and perfectly insulated it from earth, lightning would discharge to the shield, and there would be zero potential from the shield to the actual Earth either before or after the discharge. There is nothing electrically special about the physical Earth, it's just a conductor.
> Ignoring that, though, what people usually mean by this is that the combined neutrals of the entire power grid are on the other end of any dumping of current you’re doing into ground.
What you're describing only happens during fault conditions.
Except in extremely unusual circumstances like [1], the Earth is not used as a normal return path for utility neutral current. The return current flows on dedicated neutral conductors. Actually, in am ideally balanced Wye, there isn't any real neutral current at all.
[1] https://en.m.wikipedia.org/wiki/Single-wire_earth_return