So the average US household uses 900 kwh/month, equals 30kwh/day. I don't know where you learned arithmetic, but where I learned it, 60kwh divided by 30kwh = 2 days, not 5-1/2.
In a power emergency, someone who continues to use their daily average (30 kWh) doesn't understand the meaning of "emergency". I can easily get my usage down to <10kWh per day by shutting down all non-vital loads. Most refrigerators use ~2-3kWh per day. That, a couple of LED lamps, a cell-phone charger and intermittent microwave oven (and, perhaps, sump pump) use should see you through almost a week.