This is sort of a silly argument because none of these people who are responsible for the dead bears have 40 acres, but I'll humor you because the electricity bill wouldn't be much different. You don't understand how electric fences work.  If you are paying 20 cents/kw, and you are running a 50KW charger 24/7, your monthly cost would be $7.20.  40 acres means you need a mile of fence (very small by agricultural standards).