Your Powerwall will operate in a grid failure and your home will automatically switch over to the batteries. If the sun is shining when the grid goes down, your solar system will continue to charge your batteries and stop sending any energy back to the grid. We are required by code to install a “gateway” unit that relays power from your system to the Powerwall and isolates all the power in the house from the grid. This ensures the safety of lineworkers and is an automatic process when the grid goes out.