A "Grid-tie" solar system is useful for homes that are already connected to the utility grid. The advantage of this type of system is the price reduction of utility. The system has to be wired with an inverter that produces pure-sine-wave AC electricity, which is necessary for connecting to the utility grid. Another advantage to this type of system are the tax incentives and rebates available from different state and local agencies. Owning a grid-tied system in California qualifies you for the State Buydown program, drastically reducing the overall system cost. Most of these systems typically do not have the battery storage that allows for power when the utility fails. Grid-tie system can be installed with battery backup power to keep critical loads operating in the event of a power failure.