What is the "GRID" anyway? Your local electric utility company.
Grid-Tie Inverters: Grid-tie, or utility intertie, inverters convert DC power from solar panels into AC power to be fed into the utility grid through your main breaker box.
Off-Grid Inverters: Off-grid inverters convert DC power stored in batteries to AC power that can be used as needed. Select an inverter for your power system based on maximum load you will be powering, the maximum surge required, AC output voltage required, input battery voltage and optional features needed. Loads = Appliances