Rooftop solar has second coming as households electrify everything – including the car

Increasing uptake of electric vehicles and home batteries – or at least an increase in the number of households planning to buy an EV or invest in home battery storage – has helped to deliver Australia’s second biggest year for rooftop solar growth yet, new data confirms.

The 2024 Annual Australian PV Report from market analysts SunWiz reveals a total of 3.15GW of sub-100kW solar was registered across the nation in 2023, slightly less than the 3.17GW estimated earlier this month and roughly 2% shy of the 2021 record of 3.23GW.

Panels installed on rooftops make up a huge proportion of the 4.6GW in total of big and small solar installed for the year, according to SunWiz, as homes and businesses assumed the heavy lifting on grid decarbonisation – households in particular.

The report reveals that a “whopping” 2.5GW of the 3.15GW of the sub-100kW solar installed on rooftops was residential – equivalent to 6.1 million average sized solar panels.

“On an annual basis, the fast-growing 10-15kW recorded almost as much volume as the slightly contracting volume in the 6-8kW range,” the report says.

“Towards the end of the year there were months where more was recorded in the 10- 5kW range than in the 6-8kW range. Obviously the 10-15kW range is broader than the 6-8kW range, but it nonetheless marks an important industry trend.”

Another 0.9GW of all the solar installed in 2023 was made up by commercial rooftop systems – with a third of those made up of systems larger than 100kW. Solar farms, meanwhile, contributed just 1.1GW of new capacity for the year.

“Residential solar remains the mainstay of the Australian solar success story, representing more than half the total solar power installed nationwide,” the report says.

SunWiz managing director Warwick Johnston says the popularity of solar is still largely driven by basic economics, including the fact that Australia remains one of the cheapest markets to install rooftop PV.

“Despite household and business budgets being hit hard by inflation and interest rate increases, solar power systems fell in price in 2023,” Johnston said on Wednesday.

“Solar power remains the most popular way of reducing electricity bills, and it rapidly pays for itself.”

And for those installing panels for the first time, super-sized systems are the order of the day. According to the data, the average size of rooftop solar arrays grew to 9.4kW/system in 2023, a new record.

“This was driven by commercial PV having a record year, combined with strong growth of large residential systems whereas smaller residential systems segments had more stable or contracting volume,” the report says.

Johnston says anticipated uptake of EVs and batteries is a primary factor driving larger household system sizes, with many residential customers installing systems as big as permitted by their network operator.

Interestingly, the report also reveals that around 20% of the 336,000 customers who installed rooftop solar in 2023 were re-powering existing systems – that is, either boosting the size of an existing system or, more commonly, removing an older system entirely and replacing it with a new one that is bigger and more efficient.

“We’ve also seen many Australians installing larger solar systems and even upgrading existing units, in order to power electric vehicles and home energy storage systems, like batteries,” Johnston says.