The system itself
Will my solar panels work during a power outage?
The short answer
No, not on their own. A grid-tied system is required to disconnect when the grid goes down, so that it cannot energise lines that utility crews may be working on. Producing power during an outage requires a battery and switching that isolates your house from the grid, and it is designed in rather than added casually.
Why it works that way
It is a safety requirement, not a limitation of the equipment. An inverter feeding power into a de-energised network could kill someone working on it, so anti-islanding protection is mandatory. This surprises people who have just spent a lot of money and then sat in the dark, which is why it is worth knowing before rather than after.
What backup actually requires
- A battery, sized for what you want to run and for how long.
- Switchgear that isolates the house from the grid, commonly a backup or critical-loads panel.
- A decision about which circuits are backed up. Whole-home backup is possible and costs more; most installations cover selected circuits.
- An inverter capable of operating off-grid, which not all grid-tied inverters are.
Some inverters offer a limited daytime outlet that provides a small amount of power from the panels during an outage, without a battery. It is a useful feature and it is not backup power.
Also asked
Can I add backup to an existing system?
Usually, by adding a battery and switching, and sometimes by replacing the inverter with a hybrid. What it costs depends entirely on what was installed, which is why it is worth raising at the original design stage even if you are not buying it then.
General information about solar and about hiring, not advice about your roof or your tax affairs. Incentives, net metering and contractor licensing are set federally, by state, and by your utility, and all of them change. The authority that publishes the rule is the current answer.