Extreme weather is placing greater strain on Australia’s power grids. In 2022, the record-breaking Northern Rivers floods blacked out almost 70,000 households. A powerful storm in 2024 cut electricity to more than half a million Victorians. In 2025, Cyclone Alfred left 320,000 homes without power.

Large-scale power outages often coincide with mass evacuations. During the Black Summer megafires, tens of thousands of people fled.

Extreme weather will become more common and more extreme as the climate changes. Traditional far-flung power grids are often vulnerable to disasters. Trees fall on power lines, torrential rains cause outages, and bushfires can melt transformers.

Electricity is essential for emergency services, medical clinics, evacuation centres and communications systems to function during these events. Maintaining a reliable supply is a challenge.

Tapping into Australia’s growing fleet of household batteries could solve this problem by supplying electricity at local scale for hours or days, even if the grid goes down. It will take work to make this a reality, but the payoff during disasters could well be worth it.

Household storage is going mainstream

People usually use household batteries to cut their electricity bills. This works by storing excess solar energy during the day — or grid electricity when cheap — and using it later when prices are higher.

The number of household batteries installed under the federal government’s new Cheaper Home Batteries Program have now topped 146,000 in five months. The goal is to install 1 million new batteries by 2030, and the government recently boosted the program’s funding.

Batteries can be a lifeline

After Hurricane Maria devastated Puerto Rico in 2017, a combined solar and battery system restored power to a children’s hospital.

In California, battery-supported microgrids — small, self-contained energy systems that can operate independently of the main grid — kept essential services running during the intense 2025 wildfires.

The large batteries in electric vehicles are also proving their worth during disasters. When Cyclone Alfred triggered blackouts in southeast Queensland, some EV owners used their cars to power essential items in their homes.

These examples show home batteries and other local energy storage methods can be used as lifelines for communities.

People usually use their household batteries to reduce their power bills. But they can do a lot more, especially during emergencies.

They can switch to a standalone “islanding” mode, where they power essential household appliances without drawing on the grid.

Some can be relocated to evacuation centres or temporary accommodation to supply critical needs such as lighting, refrigeration and communications.

It’s important to know batteries won’t automatically act as a backup in a blackout. Household batteries have to be specifically set up to be able to cut the connection with the grid temporarily. This capability requires an inverter which supports islanding or backup operation as well as an automatic transfer switch to stop the battery feeding energy back to the grid when the grid is down.

EV batteries can be used to power houses. Trials are ongoing. Joel Carrett/AAP

Batteries beyond households

If just 10% of the Victorian households hit by the major blackout in 2024 had an average-sized home battery (currently 17 kilowatt-hours), these could have delivered as much as 900 megawatt-hours of power.

During future disasters, storage capacity at this scale would have been enough to power 10 megawatts’ worth of essential services for at least 2.5 days. We estimate that would be enough to power evacuation shelters, keep medical clinics operating and run emergency communications.

This principle is already being road tested in Queensland’s Driving Resilience project, which is exploring how mobile energy hubs can supply displaced communities with electricity during floods and cyclones. These hubs are being developed to include multiple sources of energy such as fuel cells to convert hydrogen to electricity.

The challenge will be finding ways to get home batteries to work together during disasters. One solution is linking batteries through “virtual power plants” or community microgrids, where software connects and coordinates thousands of small systems to act as one. These systems make it possible to pool and share many batteries, even if the main power grid is unavailable.

In normal times, these networks can be used to support the grid by cutting costs to consumers and making it possible for more renewable power to enter the grid. During disasters, they could be redirected to power hospitals, evacuation shelters or entire neighbourhoods.

Could battery subsidies boost disaster readiness?

If household batteries are proving their worth during disasters, could subsidy programs be reshaped to increase energy resilience?

One option could be to design resilience subsidies giving extra financial support to households in disaster-prone zones. These would include bushfire-exposed urban fringe areas, flood-prone areas near rivers and coasts or in cyclone-exposed northern regions. These extra subsidies would only apply if households commit to sharing their stored electricity during emergencies.

While some people may be concerned about installing household batteries in fire-prone areas, the risks can be reduced by ensuring low-risk battery chemistries such as lithium iron phosphate are used. The alternative – diesel generators – come with their own set of problems if there’s a fire.

A scheme like this would ensure public funds are directed not only towards reducing household power bills, but towards strengthening community preparedness. Households with batteries could pledge to support neighbours, evacuation shelters and vulnerable people in exchange for higher subsidies.

Batteries subsidies or interest free loans already exist at federal, state and territory levels.

Adding a focus on resilience would make these programs work better for households and society at large.