Do solar panels work in a power cut? (UK)

No, not on their own. Solar panels connected to the grid switch off when the power goes, even in bright sun, so they can't send electricity down a line engineers may be working on. They usually restart by themselves once the grid supply has been stable for a short while. To keep power in a cut you need a battery that's designed and installed to run your home on its own, or a portable power station.

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Why they switch off

UK Power Networks puts it plainly: "Solar panel systems are designed to shut down automatically during a power cut. This is a standard safety feature that prevents electricity feeding back into the electricity network when engineers may be working on it." The network operators' connection rules for home solar require the inverter to disconnect when the mains is lost, and to wait until the supply has been normal for at least 20 seconds before starting again.

Plug-in solar kits work the same way: the Energy Saving Trust says they "are designed to switch off if there's a power cut". How plug-in solar works.

What about a home battery?

Most home batteries switch off in a power cut too. UK Power Networks: battery systems "will usually shut down during a power cut unless they are designed to operate in backup or 'island mode'", and "Not all battery systems have this capability, and it must be specifically designed and installed." Which? advises: "Ask your installer whether your battery will work in a power outage, and for how long."

To run in a power cut, a battery system needs:

A battery and inverter that can run on their own (often called backup, island or EPS mode).
A switching unit that disconnects the house from the grid before the battery takes over, fitted by the installer. Each maker has its own: Tesla's Backup Gateway, SolarEdge's Backup Interface, Fox ESS's EPS box, GivEnergy's Gateway.
Usually an earth rod. Sunsave, an installer, says "most households' earthing capabilities will fail in a power cut, so you'll almost certainly need an earth rod installed with your home battery backup".
Some charge kept back for a cut, so the battery isn't empty when it happens.

Backup comes in levels: a single emergency socket, a few chosen circuits (lights, fridge, router), or the whole house. The more it covers, the more it costs and the bigger the battery needs to be.

What it costs

The Energy Saving Trust: home battery systems "typically cost around £5,000 to £8,000".
Which?: "from less than £2,000 up to £10,000 depending on battery capacity, type, brand and lifespan".
MCS: in 2025 the average battery installation it records was "just around £9,000".
A Tesla Powerwall 3 with whole-home backup: about £9,500 to £10,500 installed, by EnergyPlus's figures.

Switching hardware varies by system: Fox ESS's single-phase EPS box was £459.98 at Ecowizard when we checked, before fitting, and EnergyPlus lists Tesla's Backup Gateway at about £1,170. One warning from Which?: GivEnergy went into administration on 9 April 2026, and its support lines are closed, though existing batteries keep working.

The cheaper way: a portable power station

If what you want is the fridge, the internet and the lights through a power cut, a portable power station does that for a few hundred pounds, needs no installer, and can be charged from the mains before a storm or from its own folding solar panels. It won't run the whole house.

Compare them in the best portable power stations, see what one runs in the sizer, or charge one from the sun with a solar generator.