Blackouts come in different forms — there are those that affect memory, and those that affect electricity.
But no mental blank has impaired the vividness of Tom Koutsantonis's recollection of the time when, on a tempestuous spring afternoon 10 years ago, power was cut to the whole of South Australia.
Reflecting on the precise moment when the statewide blackout began, the Labor MP smiled wryly at the irony of the circumstances in which he found himself at the time.
"I was actually in the parliament on my feet moving legislation relating to the National Electricity Market (NEM),"; he said recently.
About 4pm on September 28, 2016, electricity supply to more than 850,000 properties and approximately 1.7 million residents was disrupted, leaving South Australia in darkness.
Mr Koutsantonis was then the state's minister for energy — a portfolio which, despite changes of government in the intervening years, he holds again today.
His first inkling that something was wrong was prompted by an apparent malfunction at the entrance to the parliamentary chamber.
Suspecting there had been "some sort of brownout", he was then told by an advisor that what had occurred was far worse than that.
In the same moment that Mr Koutsantonis heard parliament's doors start to glitch, energy industry analyst Danny Price was on his computer monitoring the situation closely.
"I just saw demand drop off a cliff, so I knew straightaway it was a blackout,"; he said.
"I wasn't surprised — I was watching the weather in South Australia for a day or two beforehand. You could see a very big storm was brewing."
While supply was slowly restored over the coming hours, some parts of the state were without power for more than two days.
An early estimate of the economic impact concluded that the blackout cost businesses more than $360 million — but money wasn't everything.
At Flinders Medical Centre, there were distressing consequences for prospective parents when dozens of embryos were lost at a private fertility clinic because mains supply was cut.
Twisted transmission towers
At different times, energy policy, renewables and extreme weather have each been lambasted as the prime culprit for the statewide blackout.
In a 2017 report, the Australian Energy Market Operator (AEMO) concluded that overly sensitive protection mechanisms in some of the state's wind farms were to blame.
"Activation of this protection feature resulted in a significant sustained power reduction for these wind farms,"; the report stated.
AEMO found that the sudden dip in output triggered a power surge along the Heywood Interconnector from Victoria, which in turn caused the system to trip and SA to become "islanded" from the rest of the NEM.
"AEMO cannot rule out the possibility that later events could have caused a black system, but is not aware of any system damage that would have done this."
But the causes that were most immediately obvious on the day itself were the tornadoes, with estimated wind speeds of between 190 and 260 km/h, that ripped through SA's mid north, damaging critical infrastructure.
Indeed, the most enduring imagery from the blackout is probably that of giant transmission towers lying collapsed and contorted in fields.
"Two towers had been taken down by a freak tornado or hurricane,"; Mr Koutsantonis said.
"Any time you take out transmission lines … you're going to have a shock to the system."
"That caused a sudden loss of power and the system reacted according to the laws of physics."
Mr Price also pointed to the weather — but said there was a failure of preparation at market level ahead of a "one-in-50-year storm".
"[There were not] any gas generators running, which is crazy to me,"; he said.
"What they have been doing subsequently is what they should have done at the time, and that is to spin up the thermal generators that existed in the system that would have allowed some resilience, significant resilience."
In a statement, AEMO's executive general manager of operations Michael Gatt described the blackout as a "cascading failure" that was the result of a "highly complex sequence of events".
"The lessons learned from 2016 have informed industry-wide changes and risk reporting, which have strengthened the resilience of South Australia's power system and the broader National Electricity Market,"; he said.
Universal constant of energy dispute
Perhaps the most pressing question a decade on from the South Australian blackout is not whether such an event could have been prevented, but whether one could happen today.
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Mr Price — who believes renewables need the "big buffer" of thermal generation to ensure reliability — thinks it "very easily" could.
"The system is more fragile than it was back 10 years ago. Far more fragile,"; he warned.
"We are more dependent on intermittent sources of generation.
"There's a lot more batteries out on the market but, as we know, they don't last very long and they cost a hell of a lot of money."
Mr Koutsantonis agrees that a statewide blackout "could always happen again" — but departs company with Mr Price on the likeliest circumstances, and on the impact of batteries.
"[A blackout's] probably more likely to happen in a jurisdiction that has more thermal power than renewables, because of the reliance on big suppliers from one big location,"; he said.
"Battery storage is the obvious solution — and battery storage in the right places not only stabilises your grid, it saves consumers money [and] it allows you to put more renewables into the system."
Those differences of opinion remain at the heart of Australia's energy debate.
Much has changed in the electricity market since South Australia was left in darkness.
But if there is a universal constant of the politics of power, it is surely that there is always friction over the question of what approach works best.
