A generator and a home battery both keep the lights on when SDG&E cuts power for fire weather. They do it in very different ways, and only one of them does anything for you the rest of the year.
Key takeaways
- A solar-charged battery switches on automatically during an outage. A portable generator has to be started, fueled and connected by someone at home.
- In a multi-day shutoff, fuel is a generator’s weak point. A battery refills from the panels every sunny day.
- The CPSC says never to run a portable generator in a home or garage, and to keep it at least 20 feet from the house.
- A battery also lowers bills the rest of the year by covering SDG&E’s 4 to 9 p.m. peak hours. A generator sits idle until the next outage.
- SDG&E’s 2026 Generator Assistance Program offers $300 toward a qualifying generator or $150 toward a portable power station for eligible customers in Tier 2 or Tier 3 fire areas.
Frequently asked questions
Is a solar battery or a generator better for SDG&E power shutoffs?
For automatic, whole-home or large-circuit backup that lasts through a multi-day shutoff without refueling, a solar-charged battery is the better fit. A portable generator or power station is the lowest upfront cost if you only need to run one or two appliances.
Can a Powerwall replace a generator?
In many homes, yes. Each Powerwall 3 stores 13.5 kWh, delivers up to 11.5 kW continuously and switches over automatically, and the panels recharge it during the day. Tesla says a Powerwall 3 system can provide whole-home backup to most homes, though large loads like central air and pool pumps drain it faster.
Does SDG&E offer a generator rebate?
Yes. The 2026 Generator Assistance Program offers $300 toward a qualifying fuel generator and $150 toward a portable power station ($500 and $200 total for customers enrolled in CARE or FERA) to customers in High Fire Threat District Tier 2 or Tier 3 areas who have experienced at least one PSPS. Fuel generators must be CARB-compliant and include a carbon monoxide sensor and automatic shut-off.
Where is it safe to run a portable generator?
Outdoors only. The U.S. Consumer Product Safety Commission says never to run one inside a home or garage, to keep it at least 20 feet from the house, and to point the exhaust away from windows and doors.
Will gas generators still be sold in California?
California’s Air Resources Board adopted rules under which most new portable generators made for sale in California must be zero-emission starting with model year 2028.
If you live in inland San Diego County, the question usually comes up the first time a Public Safety Power Shutoff watch lands on your phone: should we get a generator, or should we get a battery? In Poway, Ramona and San Marcos it often sounds like “do I want a backup generator or a solar generator?” Both are real answers. A portable generator is the cheapest way to keep a refrigerator cold for a weekend. A solar-charged battery is the most hands-off way to keep a whole home running for days. Here is how they compare on the things that actually matter during a shutoff.
The two ways to keep power on
Generators burn fuel (gasoline, propane or natural gas) to make electricity. They come in two broad types:
- Portable generators sit outside and power appliances through extension cords or a manually switched transfer connection.
- Standby generators are permanently installed, wired to an automatic transfer switch, and usually run on natural gas or a propane tank.
A solar-charged battery stores electricity from your panels and the grid. When the grid goes down, a backup switch disconnects your home and the battery takes over automatically. With a Tesla Powerwall 3, each unit stores 13.5 kWh and delivers up to 11.5 kW continuously, and the panels recharge it every sunny day of the outage.
How each one starts
A battery switch-over is automatic. Nobody has to be home, and nobody has to pull a cord or run an extension line.
A portable generator starts when you start it. Someone has to be home, pull it out, fuel it, run the cords and decide which appliances get power. A standby generator starts on its own, but it still runs only as long as its fuel lasts.
Fuel during a multi-day shutoff
SDG&E says a shutoff can last from several hours to multiple days, because crews must inspect de-energized lines in daylight before restoring power. That makes fuel the weak point for a portable generator. You need enough stored gasoline to run through the event, a safe place to keep it, and a plan to refill if the shutoff drags on. Gas stations inside the shutoff area may be without power too.
A battery’s fuel is the sun. During a fall shutoff, the days are often clear and bright, so the panels can refill much of what the home used overnight.
Safety: carbon monoxide
This is the biggest practical difference. The U.S. Consumer Product Safety Commission says never to run a portable generator inside a home or garage, to keep it at least 20 feet from the house, and to point the exhaust away from windows and doors. Even so, the CPSC attributes about 100 deaths a year to carbon monoxide from portable generators. A home battery produces no exhaust and can be installed in a garage or on an exterior wall.
Air rules are changing
California’s Air Resources Board adopted rules requiring most new small off-road engines to be zero-emission. Under those rules, most new portable generators made for sale in California must be zero-emission starting with model year 2028. If you’re buying a gas generator now, it’s worth knowing the direction the state is headed.
What each does the other 360 days a year
A generator is insurance. It sits in the garage until the next outage.
A battery works every day. On SDG&E’s time-of-use plans, the most expensive hours run from 4 to 9 p.m. A battery charged by midday solar can power the house through those evening hours, which is where much of the value of a solar system comes from under California’s current solar billing rules. SDG&E explains its time-of-use windows on its residential pricing plans page.
So the honest comparison isn’t generator price versus battery price. It’s generator price versus battery price minus what the battery saves on your bill over its life.
SDG&E’s Generator Assistance Program
If you just want a small backup for a refrigerator, phones and a CPAP, a portable unit can make sense, and SDG&E helps pay for it in some areas. The 2026 Generator Assistance Program offers rebates to customers who live in High Fire Threat District Tier 2 or Tier 3 areas and have experienced at least one PSPS:
- $300 toward a qualifying fuel generator
- $150 toward a portable power station
- $500 and $200 total for customers enrolled in CARE or FERA
Fuel generators must be CARB-compliant and include a carbon monoxide sensor and automatic shut-off. Many homeowners pair a small portable power station for one or two critical devices with a home battery for everything else.
Which one fits your home
| If you want… | Better fit |
|---|---|
| The lowest upfront cost for one or two appliances | Portable generator or power station |
| Automatic, whole-home or large-circuit backup | Solar plus battery |
| Backup that lasts through a multi-day shutoff without refueling | Solar plus battery |
| Lower SDG&E bills between outages | Solar plus battery |
| No fumes, noise or fuel storage | Solar plus battery |
Build the backup plan once
The right time to decide is before the next watch notice, not during it. If you’re weighing a generator against a battery, Stellar Solar can show you what your essentials actually draw and what a solar-charged battery would save between outages. Stellar Solar has been San Diego’s trusted solar installer since 1998, A+ rated with the BBB and a repeat winner of San Diego’s Best Solar in the Union-Tribune Readers Poll. Call 866.787.6527 for a free evaluation, or get your free quote here.
