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Solar vs. gas and natural gas generators
Two ways to keep the lights on. They suit different problems, and the honest comparison isn’t the one either industry makes.
The short answer: a generator is cheaper to buy. Solar with a battery is cheaper to run. If outages are rare, the generator usually wins on arithmetic. If they’re frequent — or you want the equipment earning its keep on the other 360 days a year — solar and storage start to make sense.
The comparison
| Generator | Solar + battery | |
|---|---|---|
| Upfront cost | $500–$3,000 portable; more for an installed standby unit | Roughly $17,000–$24,000 for a typical setup |
| Fuel cost per kWh | Natural gas around 25¢; gasoline roughly 73¢–$1.16 | Nothing. Sunlight is free |
| Runs during an outage | Yes, as long as fuel holds out | Yes, limited by battery capacity and daily sun |
| Value the rest of the year | None. It sits idle | Cuts your electricity bill every day |
| Maintenance | Oil changes, filters, exercise cycles, fuel storage and rotation | Minimal. The inverter is the wear item |
| Noise and fumes | Loud. Carbon monoxide risk — must run outdoors, well away from windows | Silent, no emissions |
| Multi-day outage | Fine if you can get fuel | Fine if the sun comes up — the battery recharges daily |
| Best suited to | Rare outages, limited budget, whole-house loads | Frequent outages, daily bill savings, no fuel logistics |
The fuel gap is bigger than people expect
The gap between about 25¢ a kilowatt-hour on natural gas and roughly a dollar on gasoline is the single most underappreciated number in this comparison.
A portable gasoline generator is cheap to buy and expensive to run. Over a long outage, fuel costs mount quickly — and that’s assuming you can get fuel, which after a regional storm is not a given. Stations without power can’t pump.
An installed natural gas standby unit avoids both problems. It’s plumbed into the gas line, so there’s no fuel to fetch and the running cost is far lower. It also costs considerably more to install.
A generator earns nothing on the days the power stays on. It sits in the garage, depreciating, needing to be started periodically so it works when called upon.
Solar with a battery reduces your electricity bill every single day, outage or not. Whether that closes a $20,000 gap depends on your bill and your net metering rules — but it’s the reason the comparison isn’t as lopsided as the upfront prices suggest.
Which fits your situation
A generator makes more sense if:
- You lose power once or twice a year
- Your budget is a few thousand dollars, not twenty
- You need whole-house capability including air conditioning
- Your roof is shaded or otherwise poorly suited to panels
- You have natural gas service, which makes running costs reasonable
Solar with storage makes more sense if:
- You lose power several times a year, or for long stretches
- Your electricity bill is high and you want it lower every month
- Nobody in the house wants to manage fuel, oil changes and test runs
- Noise matters — a close neighbor, or a generator running all night
- Your utility pays little for exported solar, which makes storage more valuable anyway
You can have both
Solar for the daily bill, and a modest portable generator for the rare long outage. It’s a common arrangement and often cheaper than a large battery bank.
If you go this route, the generator must never be connected to your home wiring without a proper transfer switch installed by an electrician. Back-feeding through an outlet can kill utility workers and start fires. Run appliances from the generator on extension cords, or have a transfer switch fitted.
Safety, which matters more here than anywhere else on this site
Portable generators kill people every year, almost always the same way: carbon monoxide.
- Never run one indoors — not in a garage, not in a shed, not in a breezeway, not with the door open
- Keep it well away from windows, doors and vents
- Have working carbon monoxide alarms on every level of the house
- Let it cool before refueling — spilled gasoline on a hot engine ignites
- Never back-feed through a wall outlet. Use a transfer switch
Carbon monoxide has no smell and the early symptoms resemble ordinary tiredness. That combination is what makes it so dangerous during an outage, when everyone is already cold and worn out.
Sources
- EnergySage, Home battery backup vs. generators.
- NuWatt Energy, Solar battery vs. generator cost comparison, 2026.
- Consumer Product Safety Commission, Portable generator safety.