Solar panels do not work if the National Grid is down. This is for technical and regulatory reasons. Technically, solar panels make power when the sun is up. They send extra power to the National Grid for a credit. They get power from the National Grid when they need more. This is a balance. Commercial solar helps you buy less power in the day and save money. Regulations are the other reason. Solar arrays can be dangerous for repair crews if they send power to the National Grid during outages. So energy rules say solar arrays must shut down when the National Grid is down.