As South Australians prepare for possible power cuts this afternoon, a blame game has erupted between the federal and South Australian governments over power generation.

South Australian Premier Jay Weatherill promised to “intervene dramatically in the electricity market” but failed to release any details, after thousands of homes and businesses had their power shut off last night due to insufficient generation capacity.

SA Power Networks initially said 40,000 properties had been affected, but have since revised the number to 90,000.

Mr Weatherill’s promise followed comments from Prime Minister Malcolm Turnbull earlier this morning, placing the blame for South Australia’s blackouts entirely on the State Government.

“It has created a situation where that state has the most expensive and least reliable electricity in Australia,” Mr Turnbull said.

“That is a fact. Of course they want to blame it on everybody else.

“When they have the biggest heatwave there is no wind and when there is no wind, all of their windmills are not generating electricity.

“They haven’t planned for that.”

But Mr Weatherill said South Australians were “not prepared to put up with being ridiculed and have the finger pointed at them by a Federal Government that has abdicated its responsibilities”.

“One option is to completely nationalise the system, that is an extraordinary option,” he said.

“It would involve breaking contracts and exposing us to sovereign risk and the South Australian taxpayers to extraordinary sums of money.

“It is not a preferred option. We are ruling nothing out at this point.”

He said the State Government’s plans were “well advanced” and there would be further meetings this afternoon.

“What we know at the moment is that we have a national electricity market which is all about dollars and cents,” he said.

“It is not about people, it is not about businesses and jobs.

“It is a trading system where people are trying to maximise profit and minimise cost.”

Independent senator Nick Xenophon said South Australia needed to underwrite construction of a new gas-fired generator.

“The impact of that will be immediate, it might take 12 months or so to build but it will send a very clear signal to the market both in terms of energy security and a reduction in prices,” he said.

“It will build in some real competitive tension because right now, I believe we have market failure.”

Not enough time to turn on Pelican Point: AEMO

In a statement, the Australian Energy Market Operator (AEMO) forecast “a tightening supply/demand balance across South Australia and New South Wales over the coming days”.

“AEMO understands the frustration from South Australian energy consumers … it is important to note that AEMO instructed load shedding to ease the pressure on the power system, protecting it from potentially impacting more residents, and for a longer period.”

South Australian Treasurer and Energy Minister Tom Koutsantonis earlier slammed AEMO for going ahead with a load shed rather than turning on power at Adelaide’s back-up power station Pelican Point.

But AEMO executive general manager of stakeholders Joe Adamo said they did not have enough time to switch on the plant yesterday.

“When we were talking to Pelican Point, it was decided that the lead time for Pelican Point to actually bid into the market was too short a timeframe and as such we had to take the load shedding action,” he said.

The operators of Adelaide’s back up power station at Pelican Point, ENGIE, said in statement it could not provide additional power for South Australia unless directed to do so by AEMO.

More blackouts to come

Load shedding occurs when AEMO directs power companies to start switching off customers’ power supply because the power system is at risk of failing due to too much demand and not enough supply.

Load shedding could begin from 4:00pm.

Mr Koutsantonis warned other states would also be affected.

“The problem that’s occurring here is coming to a city near you on the eastern seaboard soon.”

Adelaide’s expected top for Thursday is 42C, with Port Augusta, Coober Pedy, Woomera, Marree and Moomba forecast to reach 46C and Tarcoola 47C.

Last night, as many South Australians arrived home from work and turned on their air conditioners, SA Power Networks announced it would start load shedding to cope with demand, plunging some areas into blackouts for half an hour or more, impacting about 90,000 customers.

Thirty minutes after SA Power Networks announced the outages, it tweeted the load shedding had ended.

The reliability of South Australia’s electricity supplies has been in the spotlight after a statewide blackout in stormy weather last September, causing the Federal Coalition to criticise the state’s renewables-heavy power mix.

Another storm in December forced the power distributor to announce compensation payments totalling $20 million to about 75,000 customers after lengthy blackouts.

Today's maximum in Adelaide of 42.4°C at 4.27 pm & 5:04 pm was the highest since the 19th December 2015 when the max was 43.2°C. #sweltering

— Bureau of Meteorology, South Australia (@BOM_SA) February 8, 2017