PowerSim
I havn't studied it a lot yet, but in cities with power plants there are numbers at the beginning with power capacity and usage (some repeated several times for some reason). I have not looked at various combinations of power neighbor deals yet.
Following the beginning section of the file are dwords with a width and height of the current map. An array of integer values follows, mapping out power consumption tile by tile. In my small test city adding up each interger on the bitmap totaled the cities power consumption since there were no deals being made. This is the easiest way for the power simulator to track power usage in a city and where the power is being used at. There is also another section at the bottom of the file which seems to be another array which may map out power lines/powered areas of the map.