Australia’s main grid – known as the National Electricity Market – broke through the 50 per cent benchmark for renewable energy in one trading period on Wednesday, the first time that half of net demand had been met by renewables.

The milestone was reached at 1150 (NEM time, which is AEST), when the combined output of rooftop solar, large-scale wind, and large-scale solar reached 50.2 per cent of the near 25GW being produced on the main grid, which includes Queensland, NSW, Victoria, Tasmania and South Australia, but not Western Australia or the Northern Territory.

Rooftop solar provided nearly half the renewables output, or 23.7 per cent, followed by wind (15.7 per cent), large-scale solar (8.8 per cent) and hydro just 1.9 per cent.

The share of renewables might have been bigger were it not for four out of five solar farms in Victoria being constrained to 50 per cent of their output, along with the Broken Hill solar farm, and another solar farm in South Australia , Tailem Bend, was switched off due to low prices.

This graph above from the Energy Transition Hub’s OpenNem widget marks the occasion. It notes that batteries and pumped hydro were also in action, soaking up some of the cheap electricity on offer (prices in some states were hovering near zero at the time).

Indeed, in a later trading interval, while renewables were still contributing 49.7 per cent of net demand, the prices across all the mainland states in the NEM were at zero, or at least just above.

“It’s a magnificent and pivotal milestone,” said Angus Gemmell, the head of Solar Choice, who brought the milestone to our attention.

“At the beginning of the decade South Australia’s power system ran on more than 50 per cent wind and solar for the first time, but today it happens all the time,” Clean Energy Council CEO Kane Thornton said in emailed comments. “It is a fantastic achievement to have more than half of the National Electricity Market powered by renewable energy, and it’s worth celebrating. “A decade from now it will be completely normal as more renewable energy and storage projects are built to replace retiring coal-fired power stations.”Renewables and storage can do everything our old coal plants can do, just cheaper, cleaner and more reliably.”

Of course, 50 per cent renewables across the main grid represented the Labor target for 2030 branded as “reckless” by the current Coalition government, although Labor’s target was based on a year average, and would probably require double the amount of renewables currently in the grid, which average just over 20 per cent on an annualised basis.

State Labor governments such as Victoria and Queensland currently have 50 per cent renewable energy targets for 2030. Tasmania is already at 100 per cent, thanks to its dominant hydro supply, supplemented by wind.

South Australia has reached more than 50 per cent renewables (based on wind and solar alone which is world-leading), and aims to reach “net 100 per cent renewables by 2030, and more in the years to follow. This story goes into some detail on the way the state Liberal government is thinking about the energy transition and the economic opportunities it offers.

NSW currently has the lowest renewables share, along with Queensland, currently at 13 per cent. NSW has no interim target but a long term target of zero net carbon by 2050. And, of course, the ACT – which forms part of the NSW grid – has reached its 2020 target of sourcing the equivalent of all of its annual electricity consumption from wind and solar farms it has contracted.

At the time of today’s milestone for the main grid, South Australia was supplying more than its local demand needs from wind and solar, as it often does, Victoria was supplying 53 per cent from renewables, Queensland 45 per cent and NSW 37 per cent (and importing 16 per cent).

Some experts suggest Australia could go far beyond 50 per cent annualised by 2030. Professor Ross Garnaut, for instance, thinks 100 per cent renewables is possible by the early 2030s, part of a stepping stone towards becoming an “energy superpower.”

These thoughts are echoed by Darren Miller, the CEO of the Australian Renewable Energy Agency, who has spoken of the possibility of “700 per cent” renewables in the future, and who, like Garnaut, sees the opportunities for driving new export industries such as “green hydrogen” and “green metals”.

According to ITK analyst David Leitch, wind and solar provided 18.7 per cent of the main grid’s production on an annualised basis in recent months, while coal output has fallen 8 per cent.

The federal energy minister Angus Taylor says there is already too much wind and solar in the system.