Can a home with solar panels use a generator?
One of the biggest misconceptions about solar panels is that they’ll keep your house running when utility power goes out. However, contrary to popular belief, solar panels actually can’t send electricity to your house when the grid is out.
Why? Well, it’s a safety thing. Grid-tied solar panels send electricity to utility lines, and if they aren’t shut off during a power outage, they would continue to send electricity, posing a threat to utility workers fixing the lines. That means, in order to prevent any harm, your solar panels go out when the grid does.
So if you want your lights to stay on when the rest of your neighborhood goes dark, you need a backup plan. The good news is, homes with solar panels can be connected to gas-powered generators, but how it works can be a bit tricky.
Before we get into how generators and solar work together, let’s go over some basics about whole-home backup generators. Often referred to as ‘standby generators’, these large generators are able to backup entire homes for extended periods of time. Some popular standby generator manufacturers include Generac, Kohler, and Cummins.
The generator’s automatic transfer switch, or ATS, is able to detect a power outage and then immediately switches your home’s power source from the grid to the generator. There are multiple types of whole-home generators that run on different types of fossil fuels, including natural gas, gasoline, diesel, and propane.
Here’s the deal - even if you have a standby generator hooked up to your home, your solar panels aren’t going to turn on when the grid is down. Unfortunately, you cannot run your home with both solar power and generator power at the same time.
In other words, the generator and the solar panels cannot operate parallel to one another.
Like we said earlier, solar panels send feedback to the grid, creating a dangerous scenario for utility repair workers. Similarly, if the panels remained on, they would send feedback to the generator and thereby cause damage to the generator, the solar system, or both. Plus, the energy generators produce isn’t powerful enough to boot up most solar inverters anyway.
This doesn’t mean you can’t have a standby generator if you have solar, or that you can’t get solar if you already have a standby generator installed. There are many homes that have both solar panels and generators, especially when it comes to off-grid systems.
The panels and generator just need to be wired properly so that the two won’t interfere with one another. Your solar installer or a certified electrician will be able to help you figure out the best (and safest) way to do this.
Instead of buying a generator, you can install a solar battery to provide backup power to your home in the event of an outage. Whether a generator or a solar battery is best for you really depends on the reasons why you want to install a backup system in the first place.
A standby generator is best if you live somewhere that regularly experiences multi-day power outages and you want to be able to power your entire home, as generators offer more power than a solar battery can. Generators also tend to be cheaper than a solar battery storage system.
If you’re looking to have access to emergency backup power for a day or two that can power your most important loads (like your fridge, lights, and wall outlets to charge electronic devices), and you also want to reduce your day-to-day reliance on the utility, then a solar battery is a better choice.
Another benefit to solar batteries is that you can use them daily to maximize the amount of solar energy your home uses. Plus, a battery can keep your solar panels running when the grid is down - something a generator cannot do.
You can maximize your home's resilience against power outages by installing both a solar battery and a standby generator. Much like with solar panels, a generator and battery cannot power your home at the same time. When the power goes out, the solar battery will power your home first until it is depleted. Then the generator will kick in.
Below, solar expert William White discusses pairing solar generators and batteries with solar systems.
For most homeowners, installing backup power with your solar panels probably isn’t necessary. It costs thousands of dollars and most places in the U.S. have a fairly stable utility grid.
It’s a different story for those who do live somewhere with unreliable access to grid power. If your area experiences regular blackouts due to extreme weather events, or if you live in a more rural area, then backup power isn’t such a bad idea. You can choose either a standby generator or a solar battery, but which one is better really depends on how you want to use your backup source.
Even though a battery or a generator doesn’t always make sense for a home, installing solar panels is a different story. In most parts of the country, installing solar panels has a substantial financial benefit for homeowners and lets you run your home on clean, renewable energy.
You can use our solar panel calculator to understand what kind of savings a solar system can provide you, and what installation prices solar companies are offering in your area.