It's tempting to dismiss the extraordinary verbal blow Jay Weatherill landed on Josh Frydenberg on Thursday morning as an unprompted brain explosion.

"Unhinged" is what SA's Liberal leader Steven Marshall has branded it.

The Prime Minister said it spoke volumes about the Premier's "state of mind".

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But the reality is quite different.

This was calculated.

Watch the start of the press conference.

"Is this a bit awkward?", Mr Frydenberg is asked. "It's about to be," Mr Weatherill whispers.

For months the SA Premier has borne the brunt of the nation's energy jokes.

While electricity and solutions have been in short supply, criticism from Canberra has been flowing unhindered.

So, two days after his $500 million commitment in new energy generation was lambasted by Canberra, on the morning the Commonwealth was unveiling its own $2 billion promise of new generation in another state, the Premier seized his moment.

As is his wont.

Mr Weatherill's unassuming and quiet demeanour belies a rare political canniness.

Love or hate the Labor veteran, he's at his best on the front foot. Defining the conversation. And defining the enemy.

Especially when it changes the conversation from his Government's own failings on energy policy.

The outburst shouldn't surprise the Federal Government.

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They know all about the South Australian Premier.

Picking a fight with the feds gave Jay Weatherill a raison d'etre — on the River Murray, on the car industry, on Gonski, on submarines.

On each issue, he was brazen. And it worked. Ask Tony Abbott.

It also helped Jay Weatherill neutralise his opponents within South Australia. What sort of oxygen does a state Opposition Leader get when the main game is the fight between the Premier and the Prime Minister?

Since he released it on Tuesday, Jay Weatherill's been clutching his glossy-blue energy plan like a baby.

He appreciates the visual imagery of "having a plan".

He even tried to hand deliver a copy to Josh Frydenberg prior to their spat.

As cameras filmed official proceedings, Mr Weatherill and his Energy Minister Tom Kousantonis sat either side of the federal minister, clutching their plans and grinning.

A year and a day from now, Labor goes to an election, seeking a fifth term in Government in South Australia.

With high unemployment, and no guarantee his state's lights will stay on in the lead up to the March poll, it's hard to imagine a fourth-term government could even be in the game.

But the continued emergence of a third party, Nick Xenophon's SA Best, and Weatherill's clever campaigning, gives the ALP an opportunity.

It is just that though — an opportunity.

There is the risk of diminishing returns. How much "sticking up for one's state" can an electorate take? I don't know. But we're about to find out.