A backup power source or generator that outputs 7,000 - 9,000 watts of electricity is sufficient to power an entire home during a blackout. It’s crucial to keep in mind that you need the ability to store or generate electricity during a blackout. For example, 3.6kWh of storage or generation capacity might see you through a day of average household electricity consumption. For more extended outages, you’ll need to add additional battery storage or solar/fossil-fuel electricity generation capacity.