Does solar work during a power outage?

Will my solar panels keep working if the power goes out?

Not on their own. A standard grid-tied solar system shuts down automatically when the utility grid goes down, even in full sunshine. To keep power during an outage you need battery storage plus the switching hardware that disconnects your home from the grid and lets the system form its own supply.

Why a solar system shuts itself off

A grid-tied inverter is designed to stop exporting the instant it stops sensing the grid. This is called anti-islanding protection, and it exists so that a utility crew repairing a line that everyone believes is dead is not exposed to a rooftop system quietly energising it. It is a safety requirement, not a limitation of the panels.

The practical consequence surprises many homeowners: on a bright afternoon during an outage, a solar-only home is as dark as a home with no solar at all.

What makes solar usable in an outage

1
A battery
Something has to hold energy for when the sun is not shining, and something has to establish a stable voltage and frequency for the house. A battery system with grid-forming capability does both.
2
An automatic transfer point
The house must be electrically separated from the utility during backup, then reconnected when the grid returns. This is usually a transfer switch or a gateway device installed alongside the battery.
3
A decision about which circuits are backed up
Either the whole panel is backed up, or selected circuits are moved onto a dedicated backup subpanel. This choice has more effect on cost and on how the outage feels than the battery brand does.

What "the solar keeps charging the battery" really means

When a properly configured solar-plus-battery system is running in backup, the array can recharge the battery during daylight. That is what separates it from a battery alone: in a multi-day outage, a solar-charged battery can keep cycling, while a battery with no generation to refill it simply runs down.

The caveat is that production during a storm is not production on a clear day. A hurricane brings heavy cloud before and after landfall, so the sensible planning assumption for the first day or two is reduced output, not a full sunny-day yield.

Common questions

Can I just plug something into my solar inverter during an outage?

Some inverters offer a small daytime-only outlet that works while the sun is up, typically limited to a modest wattage. It is useful for charging phones and running a fan, and it is not a substitute for a backup system. Most systems have no such outlet at all.

Does a generator do the same job?

A generator supplies power for as long as it has fuel, which is its advantage in a long outage. It is also noisy, needs fuel that may be hard to buy after a storm, and does nothing for your bill on the other 360 days of the year. A battery is silent, automatic and useful daily, but its runtime is bounded by capacity and whatever the sun refills.

How long does the switch to backup take?

With a modern battery gateway the transfer typically happens fast enough that lights flicker rather than go out, and clocks and routers usually stay up. Systems differ, so treat this as a question to ask about the specific equipment being proposed.

Sources

What each source supports on this page, and when we last verified it. Every source we use, with its freshness policy, is listed in the source register.

Helio41 estimate methodology, version 0.1

Helio41

How Helio41 sizes an indicative system, what it models, and what it deliberately does not claim.

Verified August 16, 2026