I an pretty sure, though I may be wrong, that RF does not have any one enet, or equivalent. It is up to the cables to move power from machine to machine, thus the need to tick.
RF (TE3) Cables: You have 1 generator, 1 machine and 1000 cables between them. Every tick you have 1002 TileEntities that tick.
IC2 (Classic): You have 1 generator, 1 machine, and 1000 cables between them. Every tick you have 2 TileEntities that tick.
Now for the differece between IC2 Exp and IC2 Classic power:
If you place a cable in IC2 (both) it gets registered in a Network that stores the placed energytiles (sources, conductors, Acceptors).
Now in IC2 Classic it automaticly generates a path from Energy Sources to Acceptors. Even if you place Cables it tries that.
(Note: That i can be wrong but i readed the code for a couple hours to understand it)
Now in IC2 Exp it creates a Node that represent the EnergyTile. That node will be implemented into a grid that calculates the energy transfer. (Now to the really important info: There are the same amount of grids as Placed EnergyTiles.)
Now that covers the Registering.
Next point is the EnergyCalculation:
IC2 Classic (Immibis version):
The Generators try to send their energy to an reciver. The Energynet is only as pathfinding there.
While they send energy it also checks for nearby entities to hurt.
That will be applied when the main worldTick start.
IC2 Classic (Speigers Version):
The Energy calculation happends here after everything was calculated. That mean at the end of a worldTick.
The EnergyNet goes through the List of Energy Sources and fires for them The i want to send energy function (the same as in immibis version) that sends the energy to the Spots where it is required. Only if the can send it.
Note here: Some blocks like transformers send multible energy packets at the time. So even if you think it is sending 32 EU per tick that is not true it is sending 128 EU per tick but in 4 32 EU packets.
IC2 Exp:
Now the thing that is extremly Complicated and i can not explain the deep ways of how they do it. I Try give a short cut.
So after the main world tick is over. (Like IC2 Classic (Speigers Version)) The Energy Net start to calculate.
So the First thing what the EnergyNet does it goes through every grid and Say finish your calculations. You are simply done and stop. Nothing will happen in there. It is just required for the Restart.
After that it is clearing every Energy Transfer change that happend (for the EU Reader and Explosion(is only a guess because i never saw a explosion code in IC2 Exp!) and Detector cable).
After that is done its done it cycles again through the Grids and say them that the should prepair their calculations.
Now from here it will be hard to explain what it does:
Short form it will check for neighboar grids and setup everything what it needs. After that every grid prepaired a thread. Then the cycle ends.
After that cycle it will cycle again through the Grids and tell them that they start to calculate their energy.
What now every grid does it sends its thread to the ic2 threadpool which will do the calculation while the world is waiting for the next tick.
And here ends the world main tick now.
In the thread pool will happen now the following things:
It tells the grids to calculate how they send their energy.
How they do that? I have no clue that includes a big amount of math and calculations.
How fast they do it and How long it takes? I have no idea. As much as i know it takes to long to calculate it in a normal world to tick.