When you invest in solar panels, it’s easy to feel like you’ve secured full energy independence. You’re producing your own electricity, cutting down on your utility bills, and doing your part for the environment as well. But what happens when the grid goes down during a storm or blackout? Will your solar system keep your lights on while your neighbors sit in the dark? Unfortunately, there isn’t a simple yes or no answer to that question.
In most cases, if the power goes out in your area, so will your solar – even if the sun is shining. This is because most solar energy systems are connected to the power grid. When the grid goes down, safety regulations require your solar panel system to also shut off. To be clear, the panels are still producing electricity, they’re just not able to feed that electricity into your electrical panel to power your home. Why? We’ll explore the reasons for this below and also outline how adding solar batteries into the mix actually bypasses this limitation, allowing you to power your home – even during a blackout.
Let’s explore how blackouts affect solar power and what options you have to stay connected when the grid goes down.
Key takeaways:
- What happens to your solar power during an outage will depend on what type of solar system you have. There are three main types: grid-tied, hybrid, and off-grid solar systems.
- Most homes use grid-tied systems which are connected to the utility grid. During a blackout, these systems will automatically switch off and leave you without power.
- If you want to continue using electricity during an outage, you need to invest in a solar battery system that can store excess energy to be used during blackouts.
- Adding battery storage to an existing grid-tied solar system requires additional components, but retrofitting is possible.
What happens to solar power during a blackout?
Most homeowners with solar panels have what’s known as a ‘grid-tied’ solar system. This type of system connects your panels to an inverter that converts solar energy into usable electricity for your home. The inverter also links up with your home’s main AC panel and a solar electric meter, which records both the energy you use from the utility company and any excess power your solar panels send back to the grid. In short, a solar meter runs both directions, indicating when you’re pulling energy from the grid, or feeding energy back into it.
Grid-tied solar systems don’t usually include battery backup and they rely on the grid to store any excess electricity. When your solar panels generate more electricity than you need, any excess goes back to the grid. Depending on your utility and rate plan, you may receive a credit for this excess energy. But when the sun goes down, or your panels aren’t producing enough electricity to meet the demands of your home, the grid steps in to provide the needed power.
During a power outage, grid-tied solar systems automatically shut down. This is a safety measure to prevent your solar energy from flowing through potentially damaged power lines and endangering the workers who are repairing them. While this protects the grid, and lives, it also means your home won’t receive any power from your solar panels during an outage. The exception to this scenario is when you incorporate a battery backup system into your solar energy system. Without one, the energy your panels generate during the day goes unused while the power grid is down.
Why won’t my solar panels work during a blackout?
The reason solar panels stop working during a blackout boils down to the type of solar energy system you have installed and how it’s connected to the grid. There are three main types of systems: grid-tied, hybrid, and off-grid, and each one handles power outages differently.
Let’s take a closer look at how each of these work.
Grid-tied solar system
As mentioned earlier, grid-tied solar systems are the most common type installed in homes. These systems are connected directly to the local power grid which is used to supplement your energy consumption at night, on cloudy days, or anytime your panels cannot meet the full energy demands of your home. Conversely, when your panels produce more energy than you need, the excess power is sent back to the grid. Depending on your utility and rate plan, you may receive a credit for this excess energy.
Grid-tied solar systems will automatically shut off during a blackout. This is a safety feature designed to protect utility workers repairing power lines from any live electricity that your solar system might send back to the grid.
Hybrid solar system
A hybrid solar system provides a little more versatility than grid-tied systems. While still connected to the grid, these systems also include a solar battery to store excess energy.
With a hybrid system, the priority is to power your home with solar energy first, then draw from the battery when needed, and only tap into the grid as a final measure when the other two sources are depleted. This means you can be mostly self-sufficient but still have the safety net of grid power. Like a grid-tied system, hybrid solar systems send excess energy back to the grid, but only after your battery is fully charged.
In the event of a blackout, hybrid solar systems draw power from your solar battery to keep essential appliances running. Once the battery is depleted, the system will first look to your solar panels to recharge the battery, followed by the power grid if the outage is over. Because of the added battery, hybrid solar systems offer greater resilience during outages.
Off-grid systems
Off-grid solar systems are completely independent from the grid. This type of system is self-sustaining and relies solely on solar panels, solar batteries, and often a backup generator to supply all your energy needs.
With an off-grid solar system, you can continue generating and using solar power even during a blackout. However, these types of systems require larger solar arrays and battery banks to ensure ample power reserves are available regardless of weather and other variables. When you don’t have the grid as a safety net, the need for ample battery capacity and alternate redundant sources of power, such as generators, is critical. As such off-grid systems are typically more elaborate and more expensive than grid-tied or hybrid systems.
See More: How Does Solar Power Work?
How to keep using solar power during power outages
So, how can you continue using solar power during a blackout? You have two main options:
- Add solar batteries to your system
- Use a generator.
Let’s explore each of these options in more detail.
Add solar batteries to your system
If you want uninterrupted power during a blackout, the most reliable option is to invest in a solar battery backup system. Batteries provide peace of mind that you’ll seamlessly transition from grid power to stored energy during an outage with no down time.
There are a few options when it comes to solar batteries, including older lead acid batteries and more modern lithium-ion batteries. The best known is the Tesla Powerwall, although there are many alternatives out there with varying capabilities, capacities, and price. Your solar installer can talk you through the different options available and help you understand what the best choice is for your energy needs, home, and budget.
Unlike grid-tied solar systems, a solar-plus-battery setup allows your system to disconnect from the grid (also known as ‘islanding’) when a blackout is detected. As long as there’s still sunlight available to recharge the batteries during the day, your home can keep running on stored energy throughout the night. With this setup, you’ll be able to get through extended blackouts with no issues.
If you already have grid-tied solar, the process of adding battery storage is somewhat more complicated than simply plugging in a new battery bank. Grid-tied systems use grid-tied inverters which typically aren’t compatible with batteries. Switching to a hybrid solar system means adding new components, including a new inverter. Some newer battery systems incorporate an inverter in order to simplify the retrofitting process. A qualified battery specialist can evaluate what you already have and suggest the best option for your battery retrofit.
Keep Reading: How Many Batteries Do You Need To Run a House on Solar?
Use a generator
If a solar battery system doesn’t seem feasible for you at the moment, a more cost-effective alternative is using a generator. While less environmentally-friendly than batteries, generators are a viable alternative for keeping essential appliances running during a blackout.
How to add battery backup to a grid-tied system
As we mentioned above, adding battery backup to a grid-tied system isn’t as easy as plugging one in. Not every inverter allows you to disconnect from the grid during a blackout. For backup power to work smoothly, your entire system - solar panels, inverters, and batteries - needs to be designed for seamless switch-over during outages.
Read More: Everything You Need To Know About Solar Inverters
One way to do this is a method called AC Coupling. This involves adding a battery-based inverter, battery bank, and a critical loads panel to your setup:
- The critical loads panel is used to keep essential appliances running during a blackout.
- The battery-based inverter connects to this critical loads panel to supply power when the grid is down.
- The battery stores excess solar energy and discharges it when needed. .
This setup allows both the battery and solar panels to share power, which is why it’s called ‘AC Coupling’.
Sounds like a load of jargon? Here’s how it works:
When the power grid is working normally, your solar panels will send electricity to your critical loads panel (which powers important appliances like your fridge, lights, and medical equipment). If your solar panels produce more energy than your critical loads needs, the extra power is used to charge your battery. Once both the critical loads and battery are taken care of, any extra energy will go to your home’s main panel, helping power other devices. If there’s still excess, it gets sent back to the grid as usual.
When the grid goes down, the system works a bit differently. Your home’s main panel won’t get any power and you won’t be able to send electricity back to the grid. Instead, the system switches to focus on the critical loads panel. The battery-based inverter will continue providing power to the critical appliances and, if the sun is up, the solar panels continue generating electricity. The solar inverter is ‘tricked’ into thinking the grid is still on and continues sending power to your critical loads and charging the battery. This way, your battery can keep essential devices running, even at night.
AC coupling is the best option when retrofitting a battery into an existing solar array. If you are adding a battery at the same time as solar, DC coupling is another option. You can read more about the difference between AC and DC coupling at the link below.
Continue Reading: AC vs DC-Coupled Battery Storage: What You Need to Know.
How do I know if I need backup power?
If you’re considering solar power, or you already have a solar system without battery storage, you might be wondering if it’s worth adding backup power. Here are some questions to ask yourself when considering backup storage for solar power:
- Is your neighborhood prone to storms, bushfires, or other natural disasters?
- Are there essential appliances you need to keep powering during a blackout, such as refrigerators, medical devices, or internet modems?
- How often does your area experience blackouts, and how long do they usually last?
- Do you feel comfortable with your current setup if a blackout occurs?
Whether you have a grid-tied, hybrid, or off-grid system, the only way to keep reliably using solar energy during a power outage is to add a battery backup system. These products are designed to provide energy during outages and most contain enough capacity to power an average home overnight.
See More: How To Choose a Home Battery Backup System?
Summary: Using solar power during an outage
Despite popular belief, simply installing solar panels doesn’t mean your home is off-grid and energy independent. If you want to keep your home powered during grid outages, you need to invest in backup power for your solar system. Whether you already have an existing grid-tied system and want to add a battery, or you’re installing a completely new solar system from scratch, there are plenty of backup power options out there.
If you have any questions about adding backup power to your solar setup, or want to explore what options are available, feel free to contact the team at Sun Valley Solar Solutions. Our friendly solar consultants are here to help answer your questions and address any concerns. We provide a free, no-obligation consultation where we can discuss the best solutions for your home, budget, and energy needs. Contact us today and let’s start securing your home against power outages!