If there’s a power outage, the customer’s power will go out, too. A safety feature is required in all grid–connected PV systems that prevents the PV system from feeding back onto the utility lines. It is possible to set up a battery back-up system or a generator, but you will need a transfer switch to isolate the PV system from the generator and the electric grid. When these back-up systems are incorporated into the PV project, the price increases substantially.