A blackout in South Australia that has intensified a political brawl over energy policy was caused by three factors: demand for power was higher than forecast, wind generation was lower than forecast and several thermal generators were unable to step into the breach, according to the energy market operator.

As the partisan conflict about energy continued in Canberra on Wednesday, the Australian Energy Market Operator issued a report detailing the sequence that led to the blackout in South Australia last week – the third such outage in recent months.

Aemo said load shedding became the only option available when it became clear a gas plant at Pelican Point was not available to respond to the surge in demand as local temperatures in SA soared last week.

The market operator said it directed load shedding of 100MW to preserve the security of the electricity grid but, for reasons it still can’t explain, the local network operator shed three times that amount – 300MW.

“At 1803hrs, Aemo directed ElectraNet to shed 100MW of load,” the report says. “By 1830hrs, it was apparent that there had been a demand reduction of about 300MW,and spare capacity was available on generating units in South Australia and on the Heywood interconnector.

“At 1830 hrs, Aemo requested ElectraNet to restore 100MW of load over the next 10 minutes. By 1840hrs, Aemo had determined that sufficient generation and interconnector capacity was available to restore all load and it instructed ElectraNet accordingly.”

The market operator said it was still in the process of determining why more load was shed than the 100MW directed.

As Aemo executives testified last Friday during an appearance before a Senate committee, the operator got its forecasts wrong on the day of the blackout and “errors in the temperature forecasts led to errors in the demand forecast”.

The confluence of factors on the day, and the incorrect forecast that contributed to the necessity for load shedding, will reignite criticism about the performance of the market operator.

While it is clear the cause of the most recent blackout is multifactorial, the Turnbull government will also likely seize on the fall off in wind power to highlight the intermittency problems associated with renewable technologies.

Separately in Sydney, Australia’s chief scientist, Alan Finkel, held a public consultation that is part of the energy review he is running for the Turnbull government and states and territories through the Coag energy council.

Speaking to reporters, Finkel, dismissed the notion that recent problems with the stability of the energy market represented a crisis and he issued a clear warning against blaming any single factor.

“I don’t think that we’ve learnt that there is a single obvious problem that someone should go chasing down,” Finkel said on Wednesday. “If there was, Aemo would be chasing it down.”

He said Aemo had learned from every demand management exercise during extreme weather events.

Finkel spoke before a public meeting on the independent review of the national electricity market in Sydney, one of a series of consultations designed to inform his final blueprint.

Finkel’s preliminary report, circulated in December, warned that policy uncertainty around renewable energy was hurting investment in the industry.

Last week, a coalition of business, energy, climate, and welfare groups issued a joint statement warning that a decade of partisan politics and finger-pointing had destroyed investor confidence in Australia’s energy sector.

Finkel said recent investment in renewables had increased, despite investors expressing concern over continued policy uncertainty.

“Interestingly, what we’ve seen in the last six months, or the last few months anyway, is a bit of a resurgence in investment in wind and solar, and yet there’s no doubt that every investor group that we’ve spoken to has said that the policy uncertainty is making it much less likely that they would invest,” Finkel said.

“Where they are investing, it’s through wind and solar supported by the [renewable energy target], and of course the signals, the actual signals, are quite strong for investment. But investors have been indicating that the long-term uncertainty worries them.

“But what they say and what they do are not necessarily the same thing, and we are seeing investors coming back into the market for renewables.”