A major milestone was reached in Australia's biggest electricity market this week when renewable energy supplied more than half of the grid's power.

Key points: Clean energy sources met most of the demand on Australia's biggest grid for 10 minutes on Wednesday

Clean energy sources met most of the demand on Australia's biggest grid for 10 minutes on Wednesday Ideal weather made the milestone possible: strong winds, clear skies and relatively cool temperatures

Ideal weather made the milestone possible: strong winds, clear skies and relatively cool temperatures Observers say the industry is changing rapidly and urge governments to reform the "outdated" energy market

Green energy sources — mostly solar and wind — met most of the demand for the national electricity market (NEM) just before lunchtime on Wednesday, surpassing 50 per cent of supply for the first time.

The NEM provides power to all jurisdictions except Western Australia and the Northern Territory, which have separate grids.

Angus Gemmell, the founder and head of renewable energy firm Solar Choice, hailed the achievement, saying it showed Australia was rapidly reducing its reliance on fossil fuels such as coal.

It's a magnificent milestone that Australians can be super proud of," he said.

"It came probably a bit sooner than expected … but it's a pivotal moment to — for a 10-minute period yesterday — have more than half of all the electrons on the main grid, this vast contiguous grid, being clean and coming from renewable resources."

Green power surge

Ideal weather conditions on Wednesday had made the unanticipated achievement possible, Mr Gemmell said.

These included the combination of strong winds blowing across most of south-east Australia and a "very clear sunny day".

"Also, it wasn't super hot, so there weren't a lot of air-conditioners working across the country at the time," Mr Gemmell said.

However, industry observer Giles Parkinson, who edits the Renew Economy website, noted the 50 per cent milestone was reached even though renewable energy providers were operating below capacity.

South Australia, a renewable powerhouse, was exporting green power across its borders on Wednesday but four out of five solar farms in Victoria were not at full capacity.

Mr Parkinson said the green energy industry was poised to expand rapidly, with new solar and wind generators, as well as large batteries, about to connect to the NEM.

"What we'll see in Australia eventually is getting to 100 per cent [renewably supply] at certain times, but that excess of power won't be able to be exported anywhere — it'll have to be stored," he said.

Beyond coal and gas

Mr Gemmell said the industry was looking forward to the "rise of storage" — such as big batteries and pumped hydro-power — to allow Australians to switch from fossil fuels to clean energy.

"Like rainfall, sunlight and wind is intermittent, but just as we learned to store water and rainfall in reservoirs a long time ago, we are on a very steep growth curve towards vast amounts of storage in Australia for energy," he said.

Big batteries like the Tesla facility in South Australia will likely be a crucial part of future grids. ( News Video )

Mr Parkinson agreed, but warned a lack of direction from governments was holding back the energy revolution.

"We've been locked in a decades-old paradigm of coal providing baseload [energy] and gas providing the peak load," he said.

"Now we have a different paradigm, where the cheapest forms of generation are wind and solar."

Australia's energy markets, regulation and pricing needed to change to recognise technologies like batteries, Mr Parkinson said.

"We really need a plan to be put into place and, right now, we're not seeing that from any government, even though some of the state governments are calling out for it."