The amount of energy for a given planet is random and is probably determined by some algorithm. It's not in any of the .dat files as these files contain only data, not code. How RedEd is able to add construction yards and facilities to Coruscant, Yavin, and the HQ is beyond me. I've taken a look in the .dat file to see how it is done and found out that RebEd adds stuff to the .dat files. I'm not quite sure how they do this. I believe for the start-up facilities, RebEd edits the files: faclhqtb.dat and faclcrtb.dat. It seems that these files exist when the game is installed so editing any other system might be impossible. This would also explain why you can't edit the facilities for Yavin because of the absence of the faclyvtb.dat file. The GData folder also contains the files: cmuncrtb.dat, cmunhqtb.dat and cmunyvtb.dat. With these files present, you are able to edit the troops and fighters. So you ask, how then are we able to determine whether a system is populated or not? Because in hex code, the location where this data is located is either a 1 or a 0. A true or false. If a 0 is in the location, Rebellion randomly determines if the system is populated and how much energy the system has. If a 1 is in the location, Rebellion populates the system and since it is populated, the system energy is higher.