Despite the onset of winter, which saw overall solar generation in Australia reach its lowest month of the year, utility-scale and rooftop solar PV generation showed year-on-year growth in Australia’s National Electricity Market (NEM).
The utility-scale sector generated 1,028.4GWh of electricity, while the rooftop sector generated 1,446GWh, contributing to a spike in rooftop solar prices to AU$225.57/MWh (US$147.53/MWh) on 26 June 2025.
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Combined, rooftop and utility-scale generation in June 2025 exceeded that of the previous year; in June 2024, the cumulative total of solar PV generation in the NEM, which spans Australia’s eastern and southern coasts and Tasmania, stood at 2,135GWh. Of this, 887GWh was provided by utility-scale solar, while 1,248GWh came from rooftop solar systems.
By June 2025, the cumulative total solar generation in the NEM increased to 2,474.4GWh, representing a 16% rise. Utility-scale solar saw a 15.9% increase, while rooftop solar grew by 15.8% year-on-year.
As expected, the month-on-month cumulative total dipped by 25%, coinciding with Australia’s winter season, which typically marks the lowest period for solar generation.
Below is a full breakdown of monthly solar generation in the NEM, exclusive to PV Tech Premium subscribers. This uses data sourced from Open Electricity, formerly known as OpenNEM, which aims to make NEM and Wholesale Electricity Market (WEM) data more accessible to a broader audience.
There was a larger month-on-month decline in utility-scale generation in June 2025 than in the previous year, likely due to the increase in installed generation capacity over the year.
In June 2024, utility-scale solar saw an 11.6% month-on-month decrease from 1,004GWh to 887GWh. By June 2025, utility-scale solar dropped from 1,200GWh to 1,028GWh month-on-month, a decrease of 14.3%.
Meanwhile, rooftop solar saw a month-on-month decrease from 1,482GWh to 1,248GWh in June 2024, a 15.7% drop. In June 2025, rooftop solar dropped from 1,661GWh to 1,446GWh, representing a 12% decrease month-on-month.
26 June: a peak day for solar in Australia’s NEM
On 26 June, the cumulative total for solar peaked in the NEM, thanks to consistent generation from both utility-scale and rooftop solar. Utility-scale solar provided 45GWh, and rooftop solar contributed 55GWh, for a combined total of 100GWh.
While this was lower than the May peak of 122GWh recorded on 1 May, it marked the first time since 12 May that the cumulative total exceeded 100GWh.
Utility-scale solar peaked on 21 June with 47GWh, followed by 20 June and 26 June with 46GWh and 45GWh, respectively. Rooftop solar peaked earlier in the month, on 5 June, with 57GWh, followed closely by 10, 11, and 26 June, which all recorded 55GWh.
The average daily generation for utility-scale solar stood at 34.2GWh, while rooftop solar averaged 48.2GWh, both lower than May’s averages of 38.72GWh and 53.58GWh, respectively.
Rooftop solar prices spike to AU$225.57
Prices for utility-scale and rooftop solar remained relatively consistent, except for an anomaly on 26 June, which was also the best day for cumulative solar generation.
While the price for utility-scale solar was AU$108.05/MWh (US$70.53), rooftop solar spiked to AU$225.57/MWh, a remarkable increase given that a day prior, it stood at AU$2.05/MWh. This is a startling 10,903% increase day-on-day. It is unclear what resulted in this price spike, but it coincided with a large drop off in wind generation in the NEM, from 194GWh on 25 June to 41GWh on 26 June.
However, it is worth noting that prices spiked for every technology in the NEM on 26 June. For instance, battery discharging came in at a striking average of AU$4,938/MWh.
On the final day of the month, there was a significant increase in both utility-scale and rooftop solar prices. Utility-scale solar was priced at AU$190.47/MWh, while rooftop solar reached AU$172.42/MWh.
Unlike April and May 2025, June saw only one day when prices dropped into the negatives. The average price for utility-scale solar was AU$67.91/MWh, and the average for rooftop solar was 68.2MWh/MWh.
You can find all previous entries of the NEM data spotlight, exclusive to PV Tech Premium subscribers, available here.
