Can you still run your house on electricity from solar panels during a power cut?

Extreme weather conditions and power cuts

It’s around this time of year that we can expect more storms and extreme weather conditions. With climate change, the storms we experience here in Ireland are becoming more intense and destructive. When Storm Éowyn hit the country last January, over 725,000 homes and businesses were left without power. What might be the impact of this year’s storms? How we deal with power cuts is a big concern for many people, especially those in rural areas who were left without power for weeks. 

2025 was a record year for solar PV in Ireland. People are looking to reduce how much energy they get from the grid and save on electricity bills. More than 102,000 homes have now been grant-aided for solar panels since the scheme launched in 2018 and a third of those happened in 2025. So, what happens during a power cut if you have solar panels? Can you still generate electricity? 

What happens to your solar PV system during a power cut?

When there is a power cut i.e. the grid is down, ESB Networks crews will be working on the lines to restore electricity supply to homes and businesses. A typical solar PV installation is connected to the grid and during an outage this is automatically disconnected, preventing electricity from solar panels flowing back to utility lines. This standard safety regulation protects utility line workers from electric shock while they work to restore service. It also protects others, such as fire fighters, who may be working with power lines.

However, it is possible to have a solar PV system installed that will allow you to use electricity from your solar panels and battery in a safe way during a power cut.  

How to use your solar PV system to generate electricity during a power cut

A solar PV system can provide some electricity for a home when there is a power outage but important steps must be taken to ensure the safety of ESB Networks crews. 

First and foremost, you should contact a Registered Electrical Contractor (REC) to discuss your options. 

With or without a battery?

While it is technically possibly to use the electricity from the solar PV panels during an outage without a battery, the amount of electricity from the panels and levels of power will vary, making it an ineffective and unreliable solution. Adding a battery to the system is the only realistic way that you can have a steady, reliable supply of electricity from your PV panels to your home.    

Three possible options that work during a power cut

There are three options that allow the use of electricity from PV modules with a battery in the home during a mains outage:  

Option 1: Using a separate circuit(s) that is not connected to the grid.  

This means that the circuit is separate to the grid i.e. off-grid and so there is no risk of back-feeding electricity to the grid. However, it also means that you cannot sell your excess electricity supply as the panels are not connected to the grid. These permanently off-grid circuits should be clearly identified by appropriate warning notices. 

Option 2: A mixed set-up where some circuits are connected to the panels and the grid while the other circuits are connected to the grid only.  

The circuits that are connected to both the solar panels and the grid are disconnected from the grid during an outage but can be switched to use the solar panels. These circuits can only be connected to the panels if they have been disconnected from the grid. This switch is  known as the changeover switch and can be either manual or automatic.  The switch will only disconnect these circuits from the grid. These circuits shall be clearly identified as such by appropriate warning notices.  

The other circuits that are connected to the grid only disconnect automatically during the power outage and cannot connect to the panels. The advantage of this arrangement is that circuits connected to high power devices can remain disconnected thereby preventing the inverter from being overloaded.  

Option 3: All circuits are connected to the panels and the grid with a manual or automatic changeover switch to disconnect from the grid in the event of a power outage.   

All circuits must be isolated from the incoming grid connection, by the changeover switch, for the duration of the power outage.  Circuits are only connected to the panels during the outage. 

It is important to reiterate that with all three options, there is a requirement that the circuits connected to the solar panels, and battery, are automatically and completely isolated from the grid in the event of and for the duration of a power cut. It must also be possible to isolate all sources of electricity (grid, batteries and PV modules) at a single point in the event of an emergency.  

Contractor responsibilities

If an automatic changeover switch is used, it is the responsibility of the Registered Electrical Contractor (REC) to design the system in compliance with the National Rules for Electrical Installations (I.S. 10101) and they are required to provide the appropriate completion certificate confirming that the electrical installation complies with these rules.  

What to ask your solar PV installer?

The first thing you will need to decide is which of the three options best suits your needs. Discuss each option with your installer. Option 1 is the simplest and usually the least expensive. Options 2 and 3 are similar with the main difference being that Option 2 typically involves excluding circuits with heavy loads from overloading the inverter. Option 3 has the advantage of not requiring any change to the household circuits.  

The installer will need to identify:

• How the connection between the inverter system and the grid is isolated in the event of a power cut 
• How the circuit from the PV modules is isolated in the event of an outage 
• How the circuits are connected to the inverter only during a power cut 
• How the circuit from the PV modules is re-connected during the power cut 
• Where micro-inverters are used, how the circuit they are connected to is isolated from the grid
• How all electricity supplies (mains, inverters, PV modules) are isolated in the event of an emergency  

The REC is responsible for ensuring the system is designed in compliance with the National Rules for Electrical Installations (I.S. 10101) and they are required to provide the appropriate completion certificate confirming that the installation complies with these rules.  The installer will also need to inform you about the capacity of the inverter and how to ensure that the total load of the circuit(s) going through the inverter in a power cut doesn’t exceed the inverter capacity.   

To summarise

In summary, a solar PV system will only disconnect from the grid if the grid itself goes down, which can certainly happen during adverse weather conditions such as a storm. But homeowners who have a battery and have put one of the options above in place won't be left completely in the dark.