Do solar panels work during a power outage?

When the electrical grid goes down, most solar panels connected to that grid turn off, too—unless they're connected to a specialized inverter or a backup battery pack.

It's a safety precaution for utility workers. Most rooftop solar systems are connected to the grid so that you can sell your excess power for bill credits and other incentives. Any energy you don't use at home automatically flows into local power lines and back to the grid. However, those energized wires could pose a safety threat to electrical linemen working nearby. Once your solar array's control system senses that the grid is down, it defaults to shutting down power production until it starts receiving power from the grid again.

Couldn't your solar panels disconnect from the grid but continue to provide electricity to your home? It's trickier than it sounds for a few technical reasons, but it's possible with the right equipment.

One common workaround is to get an inverter and controller that can provide some power even when the grid connection is shut down. The Enphase Sunlight backup system (built around the IQ8 microinverter) is a popular example, though there are others. It won't be enough energy to keep your appliances running, and it doesn't work when the sun isn't shining. Still, it could be enough to keep a few critical loads active during a daytime blackout or potentially to allow you to charge your devices during extended outages.

A system that combines solar panels with a backup battery (aka solar plus storage) is a better bet for keeping your house (or parts of it) powered up during a blackout. It's a grid-resilient setup that avoids the noise and pollution of a backup generator and helps you take advantage of PV production even when you can't sell electricity back to the grid. It's a microgrid with self-contained onsite generation (solar panels), storage (battery), and electricity usage.

Ensure that whatever battery, inverter, and controllers you get can support solar islanding. They're all easy to find now but double-check with your installer at the outset of a new project so that they can design the system properly. Batteries with the ability to island can continue to receive electrical power from your solar panels and send that power to meet some of your home's electrical needs. (More on how much power a battery can provide here.)

Solar energy is a long-lasting, cost-cutting, emission-free electricity solution continuously evolving to meet the needs of homeowners and the natural environment, and adding storage increases its benefits. And battery storage paired with solar panels is a great way to save money on electricity bills in the long term. Join the EnergySage Marketplace to receive free quotes from vetted installers and unbiased guidance from our Energy Advisors. Sign up for free today to go solar with confidence!