As far as energy cost is concerned, I'd say there are two considerations: distance and mass. Now, depending on how exactly the teleportation is accomplished, distance might not be an issue (for example, if small wormholes are being generated, then distance is irrelevant, at least for fixed base-stations). However, if what we have is more Star Trek-like, then distance does matter; a distance-squared dependence for the energy cost would be appropriate and would encourage players to consider how important it was to be somewhere instantly.
The player's inventory should also play a role (teleporting more mass should require more energy). It might be prohibitive to assign an effective mass value to every item in inventory, so the number of items and occupied slots could be an ok proxy. Likewise, the occupied slots of the player's armor grid could also be considered. So, the required energy should have some kind of linear dependence on occupied slots and total items.
Finally, there should always be a minimum energy for a teleport.
Putting this all together with some numbers: If we simply assume that teleportation is about 10x faster than going by train, then the player's effective velocity is ~1 km/s. Assuming the player is 100 kg including their starting clothing and equipment, it'd take 50 MJ to get them up to that speed, and another 50 MJ to decelerate at the end. So, the basic minimum teleportation cost could be 100 MJ. Let's say that this is the minimum energy required to teleport the player up to 10 chunks, and that the cost goes as the square of the number of 10-chunk distances. And, let's say that every occupied inventory slot adds up to 5 kg to the player's mass, and every occupied equipment grid slot adds 10 kg to the player's mass. Then a fully loaded player (12 filled inventory rows, 10x10 filled equipment grid) would have an effective mass of 1700 kg, and require 1.7 GJ to teleport up to 10 chunks. More precisely, we have the following formula:
Energy (MJ) = (100 + 10 * (# filled equipment slots) + 5 * (# filled inventory slots)) * ((distance in chunks)/10)^2
The only problem is that the teleporter would need a massive internal buffer in order for this to work; a solution might be to have a second building (Teleporter Capacitor) that would give all teleporters in the same electrical network an increased buffer to draw upon.
