Solar Plus Battery vs. a Generator: The Better Backup Plan for SDG&E Power Shutoffs

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.

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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.

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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.

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Santa Ana Winds and Power Shutoffs: How Solar Plus a Battery Keeps a San Diego Home Running During a PSPS

When SDG&E shuts off lines during fire weather, the outage is planned, announced ahead of time, and can last for days. That makes it the kind of outage a home battery handles best, as long as the system is ready before the wind arrives.

Key takeaways

• A Public Safety Power Shutoff is a planned outage: SDG&E turns off lines during fire weather so damaged equipment can’t spark a wildfire.
• Santa Ana season typically runs September through December, but shutoffs don’t always follow the calendar. Both of SDG&E’s 2025 events came in January.
• SDG&E’s notices usually start about 48 hours ahead, and a shutoff can last from several hours to multiple days.
• Solar panels without a battery go dark with the grid. A battery with a backup switch keeps the home running, and the panels recharge it every sunny day.
• Size backup around your essentials and set it up before fire season, not during a shutoff watch.

Frequently asked questions

What is an SDG&E Public Safety Power Shutoff?

A Public Safety Power Shutoff (PSPS) is a preventive outage. When wind, temperature, humidity, dry vegetation and input from fire agencies point to a high wildfire risk, SDG&E turns off specific circuits until the weather passes and crews can inspect the lines.

How much notice does SDG&E give before a power shutoff?

SDG&E’s customer notices typically start about 48 hours before a possible shutoff, followed by a confirmation a few hours before power is turned off. Alerts go out by phone call, text and email, and through the Alerts by SDG&E app.

How long does a PSPS last?

Anywhere from several hours to multiple days. Crews have to inspect every de-energized line in daylight before power comes back, and SDG&E’s January 2025 event ran from January 7 to January 16.

Will my solar panels work during a power shutoff?

Not without a battery. Grid-tied solar inverters are required to shut down when the grid goes down, so the house goes dark even on a sunny day. A battery with a backup switch disconnects your home from the grid, so the solar can keep running and recharging the battery.

How many Powerwalls do I need for a multi-day shutoff?

It depends on what you need running. Each Powerwall 3 stores 13.5 kWh. If your essentials use about 10 kWh a day, one Powerwall 3 can carry the evening and overnight, and a sunny day can refill much of what you used. Central air, pool pumps and EV charging raise the requirement quickly.

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Most power outages are accidents. A Public Safety Power Shutoff is a decision. When fire weather builds in the backcountry, SDG&E can de-energize power lines on purpose so that a damaged line can’t spark a wildfire. For the homes on those circuits, the result is the same as any outage: no lights, no refrigerator, no Wi-Fi, no well pump. The difference is that you usually see it coming, and it often lasts longer than a typical outage.

That combination, advance warning plus long duration, is exactly where solar plus a battery earns its keep.

What a Public Safety Power Shutoff is

A PSPS is a preventive outage. According to SDG&E, the decision weighs wind speed and direction, temperature and humidity, how dry the vegetation is, field observations and input from fire agencies. When those conditions line up in high-risk areas, the utility turns off specific circuits until the weather passes and crews can inspect the lines.

You can see active and potential shutoffs on SDG&E’s PSPS dashboard, and SDG&E explains how decisions are made on its PSPS information page.

Why fall is shutoff season in San Diego

SDG&E describes Santa Ana wind season as typically running from September through December. Those hot, dry, offshore winds push down through the canyons of inland San Diego County, and they are the main reason shutoffs happen. They don’t always follow the calendar: both of SDG&E’s 2025 shutoff events came in January. And in early October 2026, SDG&E warned that nearly 35,000 customers, including parts of Poway and Ramona, could see their power shut off as fire weather moved in.

If your home sits in or near the inland foothills, plan for at least one shutoff watch each fall and winter.

How much warning you get

SDG&E monitors conditions days ahead. Its customer notices typically start about 48 hours before a possible shutoff, followed by a confirmation a few hours before power is turned off, updates during the event, and a notice when power is restored. Alerts go out by phone call, text and email, and through the Alerts by SDG&E app.

That lead time matters. Two days is enough to top off a battery, check which circuits are backed up and move the things you care about onto them.

How long a shutoff lasts

This is the part people underestimate. SDG&E says a PSPS can last from several hours to multiple days. Even after the wind dies down, crews have to patrol and inspect every de-energized line before power comes back, and SDG&E notes that inspection takes daylight, typically four to eight hours of it.

The January 2025 event shows the range: SDG&E’s own post-event report covers a shutoff that ran from January 7 to January 16 and affected more than 15,000 customers at various points. A plan that only covers one evening isn’t a plan for a PSPS.

Why solar panels alone go dark

If you already have solar, you might assume you’re covered. You’re not, unless you also have a battery. Grid-tied solar inverters are required to shut down when the grid goes down, so they don’t push power onto lines that crews are working on. On a bright, windy October afternoon, your panels will be producing and your house will still be dark.

What a Powerwall 3 does during a shutoff

A battery with a backup switch changes the picture. When the grid drops, a Tesla Backup Switch automatically disconnects your home from SDG&E’s lines. Your home becomes its own small, isolated system, and the Powerwall takes over.

• Storage: each Powerwall 3 stores 13.5 kWh.
• Power: it can deliver up to 11.5 kW continuously, enough to run most household loads at once.
• Solar recharge: the Powerwall 3 has a built-in solar inverter, so your panels keep charging the battery during the day while the grid is off. That’s what turns a one-night battery into a multi-day one.
• Storm Watch: once enabled in the Tesla app, Tesla’s Storm Watch charges the battery to full when alerts such as red flag or high wind warnings are issued for your area.

Sizing for a multi-day shutoff

Start with what you need to keep running, not with how many batteries you can fit in the garage. That’s the first question in any home battery backup plan in San Diego, and it decides everything else about the installation. A typical essentials list looks like this:

• Refrigerator and freezer
• Lights in the rooms you use
• Wi-Fi, phones and laptops
• Furnace fan or a window AC unit if it’s hot
• A well pump, if your property has one
• Medical devices, if anyone in the home depends on them

Add up the daily kilowatt-hours for those loads. If your essentials use about 10 kWh a day, one Powerwall 3 can carry the evening and overnight, and a sunny day can refill much of what you used. Central air conditioning, pool pumps and EV charging change the math quickly, which is why the design conversation should happen before fire season, not during a shutoff watch.

A pre-shutoff checklist

When SDG&E sends a watch notice for your area:

1. Confirm your contact information with SDG&E so you get every alert.
2. Make sure Storm Watch is on and the battery is charging to full.
3. Know which circuits are backed up, and plug essentials into those outlets.
4. Hold off on charging an EV from the battery during the shutoff.
5. Keep the refrigerator and freezer closed as much as possible.
6. Run large appliances like the dishwasher and laundry before the shutoff starts.

Get a backup plan built for your home

A Public Safety Power Shutoff is one of the few outages you can plan for, and solar plus a battery is the cleanest way to ride one out: quiet, automatic, no fuel and no extension cords. If you want a system sized to your essentials and your neighborhood’s shutoff history, Stellar Solar can design it with you. 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.

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