> Has somebody a good visual analogy for this in another medium? I mean I know that this is a case but I can not visualize the energy flowing on both sides out of the source with the medium only moving out on one side.
Imagine that for some insane reason, you set up a pipe underwater. On one end of the pipe you put a pump that pushes water into the pipe. At the other end of the pipe, you put a vacuum that sucks water out. In the middle of it, you put a turbine that powers a lightbulb. When you turn it on, energy flows from the pump to the turbine because the pump pushes the water. Energy also flows from the vacuum to the turbine because it sucks water out.
Batteries work like that, but with electrons as the medium. Negatively charged particles repel electrons, and positively charged ones attract it. So when you make a circuit, the negative terminal pushes electrons away from it and the positive terminal pulls them, resulting in both sides giving energy to the load.
> Is this how you could explain alternating current for transportation of energy?
This part I don't grasp super well, but I'll take a stab. It's a higher level thing. Resistive losses are relative to the current squared. So you want low current. But you need to deliver a lot of power, so you have to raise the voltage. Normal people's homes can't handle 200,000V power, so you have to convert it back to a lower voltage before you put it in people's homes. The cheapest/easiest way to do that is with a transformer, which requires a varying current (i.e. no DC).
Maybe you're missing a key part: all wires are already full of electricity (full of electrons.) When a current starts up, it's the wires' electrons which start moving. In a circuit, no electricity is created and no electricity is destroyed, instead it just flows around in a complete circle.
So, when energy moves from a battery and flows outwards on both wires, also the "medium" is flowing inwards on one wire, outwards on the other.
An electric circuit is like a leather drive-belt. A generator is like a pulley.
When we force the pulley to turn, the entire drive-belt must turn also. The electrons are the leather, and they go slowly in a circle. But the "work" or the "horsepower" zips instantly along the belt, moving fast as the belt moves slow.
And, if we WIGGLE the first pulley, the belt also wiggles back and forth. Yet the "work" only flys outwards from the pulley, zooming off into the distance, regardless of which way the belt is turning.
Imagine that for some insane reason, you set up a pipe underwater. On one end of the pipe you put a pump that pushes water into the pipe. At the other end of the pipe, you put a vacuum that sucks water out. In the middle of it, you put a turbine that powers a lightbulb. When you turn it on, energy flows from the pump to the turbine because the pump pushes the water. Energy also flows from the vacuum to the turbine because it sucks water out.
Batteries work like that, but with electrons as the medium. Negatively charged particles repel electrons, and positively charged ones attract it. So when you make a circuit, the negative terminal pushes electrons away from it and the positive terminal pulls them, resulting in both sides giving energy to the load.
> Is this how you could explain alternating current for transportation of energy?
This part I don't grasp super well, but I'll take a stab. It's a higher level thing. Resistive losses are relative to the current squared. So you want low current. But you need to deliver a lot of power, so you have to raise the voltage. Normal people's homes can't handle 200,000V power, so you have to convert it back to a lower voltage before you put it in people's homes. The cheapest/easiest way to do that is with a transformer, which requires a varying current (i.e. no DC).