Do Solar Panels Work During a Blackout?

Why does solar switch off when the grid goes down?

A normal grid-connected inverter needs the grid to be on. When the grid drops out, the inverter stops within moments. This is called anti-islanding, and Australian rules require it. Without it, a home system could push power into the street lines while workers think they are dead. So on a sunny afternoon during an outage, a standard solar-only system produces nothing for your home.

What do I need to keep the lights on?

You need a battery with backup. A backup-ready system includes a switch (often called a gateway or backup box) that disconnects your home from the grid when it fails. Your house then becomes its own small network, powered by the battery and, in daylight, by the panels. When the grid returns, the system reconnects.

Essential circuits or the whole house?

There are two common ways to set up backup:

• Essential circuits. Selected circuits, such as the fridge, lights, internet and some power points, stay on. This keeps the battery from being drained by big loads.
• Whole-home backup. Everything stays on, within the limits of what the battery and inverter can supply at once. Large loads like ducted air conditioning or ovens can use a lot of power quickly.

Which is right depends on your switchboard, the battery's power rating and what you want to keep running. We go through this at the site inspection.

How fast does backup kick in?

It depends on the equipment. Some systems switch over so quickly that most devices do not notice; others have a short gap. If you have equipment that must never drop out, tell us before we quote.

Can I just add backup to my existing system?

Often, yes. Many homes add a battery and a backup switch to existing solar. The work usually involves changes at the switchboard, and the right setup depends on your current inverter. Our guide on adding a battery to existing solar explains the options.

A real example

We installed 14 kW of Jinko panels with a 48 kWh Sigenergy battery in Dulwich Hill, along with a Sigenergy gateway and a 7 kW EV charger. The gateway is the part that separates the home from the grid in an outage, so the battery and panels can keep the house running.

The short answer

Solar alone does not keep the power on in a blackout. Solar with a backup-ready battery does. If blackout protection matters to you, say so at the start, because it changes the equipment and the wiring we quote.