What happens to solar during a power outage
Here's a surprise that catches many new solar owners off guard: when the grid goes down, a standard solar system shuts off too — even at high noon with the panels bathed in sun. It's not a malfunction; it's a safety feature. Here's why, and what it takes to keep the lights on.
Why it shuts off: protecting line workers
Grid-tied systems are required to stop sending power the instant the grid fails. This is called anti-islanding. If your panels kept pushing electricity onto the lines during an outage, that power could travel to downed wires utility crews are repairing — a lethal hazard. So by code, your inverter senses the outage and disconnects within a fraction of a second.
The trade-off: no backup on its own. A plain grid-tied system trades outage protection for lower cost and simplicity.
What backup actually requires
To keep power flowing safely during an outage, your system has to island — run as its own little grid, isolated from the utility lines. That takes more than panels:
- A battery — panels alone can't provide steady backup, because sun is intermittent and loads need a stable source. Storage is the heart of backup.
- A backup-capable or hybrid inverter — one designed to disconnect from the grid and safely power your home independently.
- A critical-load subpanel — most systems back up chosen circuits (fridge, lights, internet, a few outlets) rather than the whole house, which keeps the battery from draining fast. More on sizing in do I need a battery with solar?.
| Setup | Works in an outage? |
|---|---|
| Grid-tied, no battery | No — shuts off |
| Grid-tied + battery + hybrid inverter | Yes — powers backup loads |
| Off-grid | Yes — always independent |
A common middle ground
Some inverters offer a limited daytime backup outlet that provides a bit of power while the sun shines, without a battery — handy for charging a phone, but not whole-home backup. For real resilience through an evening or a multi-day event, you need storage.
Deciding if backup is worth it
If your area rarely loses power and net metering is generous, you may not need backup at all. If outages are frequent or long — storms, wildfire shutoffs, a rural line — a battery earns its keep. Weigh it against going fully independent in off-grid vs grid-tied solar.
Design and connection: not a DIY job
Backup systems switch between grid and island modes and involve significant stored energy, all tightly governed by code. A licensed electrician or PE must design and connect any grid-tied or battery system — the anti-islanding protection exists precisely because getting this wrong endangers lives. Learn the fundamentals in the reference.
FAQ
Do solar panels work during a power outage?
Standard grid-tied panels shut off during an outage for safety, even in full sun. You need a battery or backup-capable inverter to keep power flowing when the grid goes down.
Why does grid-tied solar turn off when the power goes out?
To protect utility workers. If your system kept pushing power onto downed lines, it could electrocute crews repairing them. Anti-islanding rules require it to shut off.
What do I need to keep solar running in a blackout?
A battery paired with a hybrid or backup-capable inverter, usually feeding a critical-load subpanel. This lets your system island safely and power chosen circuits.
Related: For homeowners & DIY
Educational reference, reviewed 2026-07. A design aid, not a substitute for a licensed electrician or PE. Confirm the enforced NEC edition and local amendments with your AHJ.
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