How can "...electrons flow in metals, but not in the ground..." explain grounding rods? I really enjoyed Why is the charge naming convention wrong? But, in the comments at the very end, the statement that "...electrons flow in metals, but not in the ground..." left me uneasy.
I was taught that the physical process of "electron drift" was actually quite slow, and opposite in direction to "conventional current flow". So my question is, "Why do the utility companies, who use electrons as the carriers of electric current through solid metal power lines, make so many connections to metal rods driven into the ground? Don't electrons "actually" travel from one place to another? (i.e. up from out of the ground, through the grid, and back to the station?)
 A: You are correct, electric current consists of electrons travelling from one place to another. Some materials conduct electricity better than others. Copper is one of the best and that's why our conductors are usually made of copper. Aluminium is also very good (so is silver) and high-voltage cables are usually made of aluminium.
However, everything conducts electricity to some extent. Even insulators do pass a tiny current - but they often conduct more across their (dirty) surface than through the interior. Soil and sand also conduct electricity, but their conductance is much lower than that of copper. To put it another way, they have higher resistance. If the soil is moist, the ions in the water will greatly increase the conductance.
Hence electrons will indeed flow from the copper rod into the ground. 
The comment you saw is wrong. Yes, current can be carried by positive ions (like $H^+$, i.e. protons), but they only occur because a molecule (e.g. $H_{2}O$) has lost an electron. That electron is still moving and carrying current. The electrons from the rod will ionise some of the material in the soil, but it's still electrons that do the hard work.
A: Ground is at 0 potential,so,it accepts electron from negative terminal.
And at very far place any positively charged electrode   accepts electron from ground and current flow.
