Can Heatwaves Cause Power Outages? Causes, Risks, and How to Prepare in Australia
Can heatwaves cause power outages in Australia? Yes, in fact, when high temperatures push electricity demand beyond what the grid or local infrastructure can safely supply, outages or controlled load shedding may result. In Australia, this isn’t a remote possibility but a growing risk. Planning ahead for these extreme-weather events can save comfort, costs and safety.
Why Heatwaves Lead to Power Outages
When the mercury climbs and the sun beats down, more happens to our electricity systems than just people reaching for the air-con. Heatwaves put multiple pressures on a power network — some obvious, some less so. Let’s unpack how this works.
Increased Demand
First and most simply: heat means cooling, and cooling means power. Homes, offices, retailers, hospitals — during consecutive days of high heat people ramp up their use of air conditioning, fans, refrigeration and other cooling devices. According to the Australian Energy Council, “electricity demand tends to increase in the third and fourth days of consecutive hot days, as air-conditioners increase output to manage the accumulating heat in buildings.”
In Q4 2024, the Australian Energy Market Operator (AEMO) reported a new maximum National Electricity Market demand of 33,716 MW, alongside an average underlying demand of 23,737 MW, up 2.4 % year-on-year.
The critical thing: when demand climbs close to or beyond the reliable capacity of the system, there’s little margin for error. If too many homes turn up air-con at once, for multiple days, utilities may issue “Lack of Reserve” (LOR) notices or implement load shedding to avoid system collapse.
Decreased Capacity
But demand isn’t the only problem. On very hot days the supply side also feels it. Generators may run less efficiently; transmission lines and transformers heat up and lose capacity; maintenance schedules may be disrupted; fuel supply may be constrained.
In Q4 2024, the Australian Energy Market Operator (AEMO) reported that black-coal generation availability dropped by 6.5% (-804 MW) and brown-coal availability fell by 5.9% (-228 MW) compared with the same quarter a year earlier. When demand rises and supply quietly shrinks, the system loses its buffer.
High ambient temperatures can also reduce the amount of cooling water available for thermal power plants or increase the risk of equipment overheating. In short: while demand rises, supply and infrastructure weaken.
Compounding Effect
The interplay of elevated demand and reduced capacity creates a compounding effect — more load, less cushion. Add to this the fact that many households will run air-con at the same time (evenings into overnight), meaning the evening peak shifts and rises. AEMO’s Q4 2024 report also noted “all mainland regions saw increases in average overnight operational demand … with higher minimum temperatures recorded in all major cities compared to the previous year.”
So while the grid may historically have managed day-peaks, it may be less prepared for sustained high loads, elevated overnight minima, and the reduced effectiveness of equipment in extreme heat.
Infrastructure Strain
Finally, we must consider infrastructure— the wires, transformers, substations, and distribution network. These wear down faster in heat, are more likely to fail or degrade, and often were designed in less extreme climates than we now face. When equipment gets too hot, protective systems may trigger shutdowns.
Beyond cooling demand, high heat can degrade insulation, increase line losses, and reduce the margin for failure. When you combine: (1) high load, (2) stressed generation & transmission, (3) hot ambient temps — you get a ripe scenario for power outages.
Real-Life Examples from Australian Heatwaves
Australia has a long list of moments where the heat didn’t just feel oppressive — it pushed the electricity system to breaking point. Here are a few events that show how quickly things can unravel when extreme heat lingers.
2019 Victoria Heatwave — Load Shedding Across the State
Late January 2019 delivered consecutive 40 °C+ days across Victoria. Demand surged past secure limits, forcing AEMO to order controlled load shedding that affected more than 200,000 homes and businesses. Transformers overheated. Air-con demand spiked. It became one of the clearest examples of heat alone tipping the grid off balance.
2020 NSW Heatwave — Overheating Equipment + Bushfire-Weakened Lines
During the Black Summer period, extreme heat hit NSW while transmission assets were already stressed from fires. Temperatures exceeded 45 °C in several regions, causing multiple network trips and pockets of outages. People weren’t even in the fire zones — the heat simply pushed equipment past thermal limits.
2023 South Australia Heat Surge — Night-Time Demand Shock
Adelaide’s run of scorching nights in early 2023 brought another kind of problem. Minimums stayed above 30 °C, so households kept their air-cons running overnight. Evening and late-night demand rose to near daytime levels, stressing feeders that normally cool down after sunset. The result: localised outages and voltage dips across suburbs.
2024 Queensland & NSW — Record Demand Meets Reduced Capacity
In Q4 2024, heat-stress days pushed the NEM to a new maximum demand of 33,716 MW, at the same time coal availability had dropped by over 1 GW compared to the previous year. The grid didn’t fail, but AEMO issued multiple alerts, spot prices went up, and load-shedding was on the table during back-to-back hot evenings.
These events all point to the same uncomfortable truth: you don’t need a cyclone or a bushfire to lose power in Australia. Sometimes heat, all by itself, is enough.
How to Prepare Your Home or Business for a Heatwave-Related Outage?
With the risk established, the question is: what can you do? Staying prepared rather than panicking is key. Portable power solutions, like EcoFlow devices, can help homes and businesses remain powered and safe during heatwave-related outages.
Cooling & Indoor Environment
Prioritise efficient cooling. Run air-conditioning early (off-peak) to pre-cool the building rather than waiting until heat peaks.
Consider a portable air conditioner that you can move to the most used room — this costs less than cooling a whole building at max output.
In extreme heat or during outage preparation, a flexible unit like the EcoFlow WAVE 3 Portable Air Conditioner can be moved between rooms to keep the areas you rely on most at a safe temperature.
EcoFlow WAVE 3 Portable Air Conditioner
Use blinds, curtains, awnings and shade to reduce solar gain so your cooling system works less hard.
Maintain roof insulation, proper ventilation and fix any leaks of hot air into conditioned spaces.
Food Safety & Refrigeration
A blackout during a heatwave means your fridge/freezer contents are at risk. Have a plan for at least 24 hours of outage tolerance.
Consider items like the EcoFlow GLACIER Classic Portable Fridge Freezer — ideal for keeping essentials chilled or frozen when the grid drops.
Keep a thermometer in your fridge and freezer. If the temperature rises above 4 °C for more than 2–3 hours (fridge) or –18 °C begins warming (freezer), move perishables or use cold packs.
EcoFlow GLACIER Classic Portable Fridge Freezer
Backup Power & Resilience
Businesses should assess essential loads: servers, HVAC, lighting, refrigeration. Have a backup plan or generator.
Homes should consider portable energy storage, battery systems or even solar + battery if feasible. A reliable backup allows you to ride through short blackouts.
If you use medical or mobility equipment that requires power, ensure you have alerts, backup power or access to a cooler location.
Communication & Planning
Monitor your local grid operator. For example the Essential Energy power outages map may show planned outages or load-shedding zones; while not guaranteed, watching for alerts helps.
Prepare a ‘kit’: battery-powered radio, torch, extra water, fan, blankets (for nights if temps drop), and contact info for support.
For businesses: schedule non-essential tasks (printing, large manufacturing) during cooler times, implement energy-saving measures when heatwave alerts are issued.
When Outage Happens
Turn off or unplug sensitive electronics to protect from surges when power returns.
On power return: check freezer contents, check perishable food, reset alarms.
In heat: avoid strenuous activity, stay cool, drink water, use shade; a power failure during a heatwave raises health risks.
By taking these steps, you reduce the likelihood that a heat-induced power outage will become a major disruption for your home or business.
Conclusion
So, Can heatwaves cause power outages? Yes, heatwaves can cause power outages — especially in Australia where high demand, stressed infrastructure and rising temperatures intersect. But power failure needn’t become a catastrophe. Stay aware of heatwave alerts, prepare what you can, and give yourself enough resilience to stay comfortable when the grid struggles. Australia’s summers aren’t getting milder, but your response can be smarter.
FAQs
Do heat waves cause power outages?
Yes — during prolonged high temperatures, electricity demand rises significantly (due to increased use of cooling), while supply and infrastructure capacity can be reduced (due to heat stress on equipment). The combination means the grid may need to cut load to maintain safety. In Australia this scenario is increasingly recognised.
Why does power go out on hot days?
Power may fail during hot days for a few reasons:
The sheer volume of air-conditioning load can push demand above safe margins.
Equipment such as transformers and lines run hotter and may be derated or fail.
Generation plants may run at reduced efficiency or be offline.
To protect the grid, utilities may stage planned outages or load-shedding.
The result: your lights go out even though it’s simply “too hot.”
What weather causes the most power outages?
While storms, floods and bushfires are well-known causes, extended heatwaves (especially consecutive days of high temps with little relief overnight) are increasingly problematic. They cause cumulative stress on both the load side and the supply side of electricity networks. In fact, Australian analysis highlights that heatwaves plus ageing infrastructure create what they describe as “real blackout threats.”
Is it dangerous when power fails in extreme heat?
Yes — a power outage during a heatwave is more than an inconvenience. Without cooling you risk heat stress or heat stroke, especially if you’re elderly, ill or very young. Refrigeration fails, medical equipment may lose power, communications may be disrupted. A joint CSIRO/Energy Networks Australia report emphasises that the combination of power loss and extreme heat can markedly increase vulnerability of Australians.