Quick answer
Not on its own. A standard grid-tied solar system shuts off automatically during a ComEd or Ameren outage so it can't send power into lines that utility crews are repairing. To keep power on, you need a battery with a backup-capable inverter, which ComEd and Ameren help pay for with a storage rebate of about $300 per kWh. Some inverters also offer a small daytime-only emergency outlet.
Why do solar panels shut off when the power goes out?
Grid-tied inverters are required to stop exporting power within about two seconds of detecting an outage, a safety feature called anti-islanding. It keeps your panels from energizing lines that line workers believe are dead. The requirement comes from the IEEE 1547 interconnection standard and the UL 1741 listing that home inverters must pass, which is part of what ComEd and Ameren check when they approve your system.
A standard inverter also needs the grid's voltage and frequency to run, so even a sunny day doesn't help without extra equipment.
How can solar keep my power on during an outage?
| Option | What it powers | Works at night? | Notes |
|---|---|---|---|
| Standard grid-tied solar | Nothing during an outage | No | Shuts off automatically for safety |
| Inverter emergency outlet | One outlet, typically about 1,500–2,000 W | No | Only on some inverter models; only while the sun is up |
| Solar + battery (essential loads) | Chosen circuits: fridge, lights, internet, sump pump, furnace fan | Yes | Battery recharges from solar during the day |
| Solar + larger battery (whole home) | Most or all circuits | Yes | Needs more capacity and a bigger budget; central AC and electric heat drain batteries fast |
| Standby generator | Whole home, as long as fuel lasts | Yes | Separate from solar; needs a transfer switch |
A battery system disconnects your home from the grid during an outage and runs it as a small island, which meets the safety rules. ComEd and Ameren offer a storage rebate of about $300 per kWh, generally tied to enrolling in a time-based rate. See the Illinois battery rebate guide.
How much battery do I need to get through an outage?
Size backup for the circuits you can't live without, not your whole bill. Rough daily use for common Illinois essentials:
| Load | Typical daily use | Why it matters in Illinois |
|---|---|---|
| Refrigerator | 1–2 kWh | Food safety in a summer storm outage |
| Sump pump | 0.5–2 kWh, more in heavy rain | Spring and summer storms often bring both outages and flooding |
| Gas furnace blower and controls | 2–5 kWh on cold days | A gas furnace can't run without electricity |
| Lights, internet, phone charging | 1–2 kWh | Staying connected |
| Well pump (rural homes) | 1–3 kWh | Water supply |
A single battery of about 10 to 13.5 kWh typically covers essentials for a day or more, and solar can recharge it on sunny days. Your installer should size it from your actual loads.
What should I ask installers about backup power?
- 1
Which circuits will be backed up?
Get the list in writing; most systems use a separate backup or critical-loads panel.
- 2
Will solar recharge the battery during an outage?
It should, but confirm the inverter and battery are set up to do it.
- 3
How does the switchover work?
Ask whether it's automatic and how long the lights blink during the transfer.
- 4
What does the battery rebate require?
Confirm the time-based rate enrollment and how the utility may use the battery at peak times.
Compare backup costs alongside savings in the solar savings calculator.
Sources
- Penn State (EME/AE 868): Interconnection codes, IEEE 1547 and UL 1741
- Green Building Advisor: Getting power from solar equipment when the grid is down
- Citizens Utility Board: Solar and storage rebates (ComEd and Ameren)
- ComEd: Distributed generation rebate
- U.S. Department of Energy: Homeowner's guide to going solar
This guide is general information, not tax, legal or financial advice. Incentive programs change, so confirm current terms with your installer, your utility and a tax professional.