This type is very similar to an off-grid system in design and components, but adds the utility grid, which reduces the need for the system to provide all the energy all the time. The battery bank provides backup to some or all loads during utility outages. Battery backup can be provided for any household circuit, but common backup loads include refrigeration, a well pump, or a computer. Including batteries in a grid-tied system requires more components, is more expensive, and lowers the system’s overall efficiency compared to a batteryless grid-tied system. But for homeowners who regularly experience utility outages or have critical electrical loads, having a backup energy source can be important.