As we all just went through the significant power outage that impacted all of San Diego County, I received a number of questions about the role of solar PV systems under such conditions. I thought it would be useful information to share. Unfortunately, most PV systems also shut down in a grid outage. All grid-tied solar inverters have to meet the UL1741 safety requirement, which is known as “anti-islanding.” This means that if the inverter does not detect presence from the grid, it has to shut itself down in a millisecond, and it would not be operational in a grid outage. However, it is possible to keep the inverter working if you create your own “artificial autonomous grid” usually from batteries, or a generator, which has to be decoupled from the public grid with a transfer switch. Typically, you would have a separate critical loads sub-panel for the circuits you want to keep powered up, such as refrigerator or lighting. If you have such a system installed with your solar PV system then you would be self-sufficient even during a power outage. As a full-service solar contractor, we have the expertise to design a new system or upgrade your existing PV system with either battery or generator back-up, or both. Do not hesitate to contact us for any further questions.