Rooftop Solar Taming Australia’s Summer Sizzle

Air-conditioners were working hard during the recent heatwave that affected large parts of Australia — and rooftop solar power systems did their bit to alleviate strain on the mains grid while making air-con use greener and cheaper.

How Much Electricity Was Supplied By Rooftop Solar Panels?

From about 4.30AM last Monday January 5, 2026 to the same time this morning (January 12), rooftop solar contributed 18.8% to overall electricity demand in the National Electricity Market (NEM – QLD, NSW/ACT, VIC, SA and TAS) and Western Australia’s South-West Interconnected System (SWIS). Utility-scale solar kicked in another 10.3%.

The maximum contribution from rooftop solar systems installed in NEM regions was 46.9% on Monday, January 5 at 12PM, followed by 45.9% on Wednesday, January 6 at midday. Overall for the period, all renewables met 49.9% of demand.

Here’s what happened in each state and territory for the period (aside from NT – I don’t have figures) based on data sourced from Open Electricity:

Queensland:

• Demand met by rooftop solar: 14.7%
• Amount of solar electricity consumed:  226 gigawatt hours (GWh)
• Maximum contribution: 37.9% (January 6, 12PM)
• Overall renewables share: 41.6%

New South Wales/ACT

• Demand met by rooftop solar: 16.4%
• Amount of solar electricity consumed: 290 GWh
• Maximum contribution: 47.1% (January 6, 12:30PM)
• Overall renewables share: 44.7%

Victoria

• Demand met by rooftop solar: 16%
• Amount of solar electricity consumed: 202 GWh
• Maximum contribution: 59.4% (January 5, 12PM)
• Overall renewables share: 51.3%

Tasmania:

• Demand met by rooftop solar: 7.0%
• Amount of solar electricity consumed: 13.5 GWh
• Maximum contribution: 23.6%  (January 5, 11.30AM)
• Overall renewables share: 89.4%

South Australia:

• Demand met by rooftop solar: 66.6%
• Amount of solar electricity consumed: 1,510 GWh
• Maximum contribution: 81.4% (January 10, 2.30PM)
• Overall renewables share: 94.7%

Note: I originally recorded figures yesterday, then when checking them again this morning on Open Electricity, they were really off (much lower) for South Australia. So I’ve opted to use January 4 to January 11 figures originally recorded as they seemed to align better with what was happening when I was checking SA from time to time during that period. I’ll check the figures again in the coming days and adjust if necessary.

Western Australia

• Demand met by rooftop solar: 27.6%
• Amount of solar electricity consumed: 130 GWh
• Maximum contribution: 60.7% (January 9, 1.30PM)
• Overall renewables share: 52.5%

In a graph:

New Electricity Demand Record Set

The period saw underlying NEM demand jump to a record high of more than 40,000 megawatts at one point and January 7-9 saw the highest electricity demand in the NEM during the January 5 – 12 period.

Hot summer days have been challenging for electricity networks, striking fear into the hearts of grid operators as high temperatures drive the increase use of air-conditioners.

But in part thanks to rooftop solar panel installations, Global Power Energy’s Geoff Eldridge said there were no Lack of Reserve notices, no calls for emergency reserves, and prices were largely stable in the middle part of the day. Wholesale spot prices even went negative at times, which is becoming increasingly common.

“Peak [underlying] demand is higher than it was in 2019, and summer heat remains a defining challenge,” he said. “What has changed is how the system absorbs that challenge. Solar now carries much of the heat-driven load during the day.”

The remaining challenge for summer is in the evenings, when panels are no longer producing power. But even that will become less of an issue in the years ahead thanks to the Cheaper Home Batteries program (CHBP). More than 175,000 home batteries have been installed since the program formally launched in July 2025. These batteries will serve their owners well, helping to power their homes during evening peak, and put downward pressure on wholesale power prices — benefiting everyone.

The week also would have been a good test of how home batteries cope with extreme heat.

Beyond home solar batteries, there are also plenty of utility scale energy storage projects being built — there seems to be project announcements every other day at the moment.

Virtual Power Plants Yet To Shine

Another key element in taming the electricity system are Virtual Power Plants (VPPs). These are  networks of distributed energy resources such as home batteries and solar panels centrally controlled by a third party and smart software to act as a single power source, balancing the grid and reducing peak demand.

But Virtual Power Plants are yet to really take off in Australia; even though we supposedly lead the world. Battery owners are still suspicious and concerned about various issues such as how hard a VPP operator might hit a battery and the impact that may have not only on battery warranty, but longevity.

According to this report from the Australian Competition and Consumer Commission (ACCC), around 38,200 Australian households were participating in VPPs by January last year, with adoption increasing nearly 22% every six months over the prior two-and-a-half years.

However, participation still trails well behind stand-alone battery installations. While there is a requirement under the CHBP that solar batteries installed be VPP *capable*, it is not required to join a program. But there can be added incentives for doing so. For example, In New South Wales and South Australia there is a payment available for connecting batteries to a VPP.

You can compare what’s available across Australia on SolarQuotes VPP comparison page.

By the way, you can also check out how rooftop solar performed on Xmas day 2025 here.