More and more homes have a solar panel installation to reduce their electricity bill and rely less on the grid. However, a very common question among people who have or want to install solar panels is this: if the power goes out, do solar panels still work? This depends on the type of installation you have.
In most domestic installations connected to the electricity grid, on grid systems, solar panels stop working when there is a power cut, even if it is a sunny day. This may seem surprising, since many users think that by producing their own electricity they should still be able to have power during an outage.
However, there is an important safety reason behind this behaviour. That said, there are exceptions. If your installation has solar batteries or a backup system, it is possible to continue having electricity at home during a blackout, so we are going to explain in detail what happens if the power goes out and I have solar panels.
What happens if there is a blackout and I have solar panels without a battery
In most homes with conventional solar installations connected to the electricity grid, the solar panels automatically stop working when a blackout occurs. This happens even if the panels are generating energy at that moment. The main reason is a safety system called anti islanding, which is integrated into solar inverters.
Why do they disconnect?
When there is a power cut in the electricity grid, the solar inverter detects that the grid has stopped working and disconnects automatically. This mechanism exists for safety reasons, because if the panels continued sending electricity to a damaged grid, dangerous situations could arise for:
- Technicians repairing the electricity grid
- Electrical equipment belonging to the electricity company
- Infrastructure damaged by the blackout
For this reason, solar systems connected to the grid are designed to stop feeding energy into it when the grid goes down. This means that even if your roof is full of solar panels and there is bright sunshine, your home will still be left without electricity just like the rest of the homes connected to the grid and this is, in fact, an essential mandatory feature in practically all grid connected photovoltaic installations.
What happens if the power goes out and I have solar panels with a battery
The situation changes quite a lot when the solar installation includes domestic batteries, because in this case, it is possible to continue having electricity at home during a blackout, as long as the system is prepared to operate in backup mode.
Solar batteries store the energy produced by the panels during the day and allow it to be used when there is no solar production, such as at night or during a power cut and, when a blackout occurs, some systems with batteries can automatically isolate the home from the electricity grid and continue operating independently, which is known as island mode. In this case, the solar installation continues working in the following way:
- The solar panels continue producing electricity if there is sunlight.
- The energy can directly power the home.
- The surplus can be stored in the battery.
The battery supplies energy when there is no solar production, so thanks to this system, a home can continue having electricity for lighting, appliances, electronic equipment, routers and communication devices, and so on. Of course, the autonomy will depend on several factors, such as the capacity of the battery and the home’s energy consumption, but in any case, having batteries for solar panels is one of the best solutions if you want to guarantee electricity supply when there is a blackout.
Key aspects to have electricity with solar panels during a blackout
If your goal is for your home to continue having electricity during a power cut, it is important to take some fundamental technical aspects into account.
Solar inverter safety
As we mentioned earlier, the solar inverter includes a safety system that automatically disconnects the installation when it detects a fault in the electricity grid. This mechanism prevents the energy produced by the panels from being fed into a damaged grid, which could put the technicians repairing the fault at risk. For this reason, a solar installation connected to the grid does not work during a blackout if it does not have additional systems.
The importance of batteries and the backup system
To be able to continue having electricity during a power outage, it is necessary to have:
- Solar batteries
- A hybrid inverter or backup system
These types of systems allow the home to be isolated from the electricity grid and continue supplying the internal circuits with the energy produced by the panels or stored in the batteries. Some installations even allow priority circuits to be configured, so that only certain essential devices continue working during the blackout.
Off grid solar systems
There is another scenario in which external power cuts do not affect the home: isolated or off grid solar installations, because in these systems, the home is not connected to the public electricity grid. All the energy comes from solar panels, storage batteries and, in some cases, backup generators.
In an off grid installation, blackouts in the electricity grid simply do not affect the home, because it operates completely autonomously, and for this very reason this type of system is usually used in rural homes, isolated houses or areas where the electricity grid does not reach.
In short, if you are wondering whether solar panels work when the power goes out, the answer depends on the type of installation you have. If your system is connected to the grid and does not have batteries, the solar panels will stop working during a blackout for safety reasons, but if you have batteries and a backup system, you will be able to continue having electricity at home for as long as the power cut lasts.
