This document discusses grid-interactive photovoltaic (PV) systems that incorporate energy storage. A grid-interactive system intelligently applies stored solar energy as needed, rather than solely for backup purposes as in traditional grid-connected battery backup systems. Emerging technologies like the Fronius Energy Cell, a hybrid fuel cell with integrated inverter, allow PV systems to store excess solar energy for use when solar power is unavailable. Grid-interactive systems provide installers and consumers more flexibility than traditional net-metered systems. For a sustainable energy future, both centralized and distributed energy storage will be important at utility and residential scales to optimize renewable energy use.