your electric bill can fluctuate as much as you want, the elect company doesnt tell the cops about that stuff, unless they ask, and if you think the cops are asking the electric company for your power use (ie they already suspect your growing and are investigating you) you prolly shouldnt be growing in the first place, as for the choppers, chances are they arnt gunna spend the money flying over neighborhoods looking for abnormal heat sources, cops rnt gunna use these investigative resources unless they already suspect something in the first place, so just keep everything on the DL and you should be fine