Storing electricity in a battery bank can serve many purposes. In most parts of the country, battery storage for is mainly used to provide backup power during power outages.
When the utility grid goes down and you lose electric service, you can use a battery system to power some or all of your electricity needs (called “loads”). The battery backup system works by isolating certain loads from the main utility system with something called an “automatic transfer switch”. You are then able to power these loads with electricity stored in the battery bank. Loads can range from small (light bulbs, a toaster, or microwave) to large (a refrigerator or a well pump). When the utility grid power returns, the backed-up loads in your home then automatically reconnect to the grid. The result is that these “critical” loads receive power even when the grid is down, switching seamlessly between utility electricity and stored electricity from your battery.
