This is one of the biggest misconceptions in the solar industry. Here’s the truth about solar and power outages.
It’s one of the questions we hear all the time: Will solar panels work if the power goes out?
Short answer: No. But that doesn’t mean you’re totally in the dark. Rob Dunn, Project Manager and Battery Expert at Green Mountain Solar, explains why solar panels don’t work in a blackout and how to work around it.
Why Don’t Solar Panels Work in a Blackout?
“The goal of solar is to produce the most that we can,” explains Rob. “Oftentimes, you can't use the power being produced. So, we send it back to the grid. Then your neighbors can benefit from it, and you can get compensated from the utility for all the energy you produce.” (This is net metering in a nutshell. More on that here.) “You don't need to turn off your solar just because you can't use it at that point.”
So that’s a win—you get to save money off the power you can’t use. (Because without the grid or other electricity sink as a buffer, if your panels made more power than you could use right at that moment, you could cause damage to your home or solar system.)
However, this becomes a safety issue during a power outage. “Your solar has to stop producing, or you could put the linemen who are trying to fix those electric utility lines at risk,” Rob explains.
How Can I Keep My Solar Working in a Power Outage?
Here's one big piece of good news: If you have a backup battery, your solar will keep producing.
Consider a scenario like this: On day one, there’s a big thunderstorm and the power goes out. It’s not sunny enough for your panels to make much power, but your battery kicks in and keeps your home running—lights, fridge, etc. On day two, if power hasn’t been restored yet, but the clouds have cleared and it’s now a sunny day, your panels are back in the game making enough power to run your home and recharge your battery. (“Your home is going to use any of the produced solar power before it even goes to the battery, which increases the utility of the system,” Rob adds.)
Learn more about backup mode and other ways to use a solar backup battery.
“Battery backup systems have these devices to disconnect your home from the grid when you have a blackout,” Rob explains. “The idea is that this battery then becomes your buffer for that solar production—it can store any energy being produced that otherwise would have no place to go and it can even turn your solar off if it needs to.”
Rob says it’s very similar to an automatic transfer switch for a standby generator. “If you're familiar with how a standby generator has to turn off the grid to produce power for your home, it's the same concept but just with solar and batteries instead.”
This means a few different things for your solar and your battery: First, it means that you have backup power stored in your battery to run your home. And, because you’re temporarily disconnected from the grid, it means that your solar will keep producing power, keeping your battery charged.
Generator vs. Backup Battery for Home
Speaking of a generator, Marcus Shapiro, Senior Solar Advisor, rattles off several reasons why many people opt for a battery over a generator: “They're quiet. They're not stinky, no fossil fuels, no maintenance, no lag time when it kicks on.” And while portable generators are less expensive, a more apt comparison is a whole-home generator, which is going to be much closer in terms of cost.
What Can I Power with a Battery?
“So, it all depends on the size of your system, but we can do a lot more with the batteries that we have available now than we could five or 10 years ago,” says Rob. “Typically, everything beyond really heavy loads (you know, big motors turning on), we can do fairly comfortably.”
This includes things like lights, the fridge, freezer, your internet router, even an electric range—they can all be powered by a battery. “You should probably use your oven conservatively, you know—like one or two burners on medium or one on high. You can definitely boil a kettle of water, but maybe don’t cook a turkey.”
Appliances that may be too large for a conventionally sized system include heat pumps, big air conditioners, and power tools. But when the system is designed with your needs in mind, it should be able to handle just about anything.
By Julia Westbrook