EMMA ALBERICI: To a developing story now:

The ABC has confirmed that the former Prime Minister Malcolm Turnbull will resign from Parliament later this week.

For at least two sitting weeks, the Federal Government will then hold just over 75 of 149 - just over half, rather - 75 of 149 seats in the House of Representatives.

Mr Turnbull's resignation will trigger a by-election in his Sydney electorate of Wentworth.

Energy policy was central to Malcolm Turnbull's political demise. It has also been at the heart of his son's investment banking career.

Alex Turnbull lives in Singapore, where he runs his own hedge fund.

When I spoke to him earlier, I asked him to reflect on the end of his father's time as prime minister.

ALEX TURNBULL: You know, I'm very proud of him.

Look, he's been a voice for moderation, and reasonableness, and sanity, and getting things done, despite overwhelming odds—and I’m proud of what he's done in numerous areas.

Climate has been ferociously difficult, and has claimed however many prime ministers one can count over the last decade.

And it remained a serious challenge and one of profound public interest.

EMMA ALBERICI: Ironically, the challenges of climate and energy policy that contributed to his father's downfall also made Alex Turnbull a load of money.

Before his father became prime minister, Alex Turnbull was speculating on the value of energy company debt, working for Goldman Sachs, when the then-Labor government was also wrestling with climate policy.

Alex Turnbull joined me earlier.

ALEX TURNBULL: Every time you have a cycle of panic and mania, and there are—these things occur regularly in financial markets with zero government inducement, that creates opportunities for people like me.

What's happened in Australian power is, in a sector which is naturally extremely boring, government policy has created cycles of mania and panic, which has created a lot of opportunities, and that's all been—a lot of that's all just policy volatility.

EMMA ALBERICI: Why have you decided to speak out on this?

ALEX TURNBULL: Because I'm a free agent now and I can express my opinions as on how I please.

And I have been quietly very frustrated at how unproductive policy-making has been in this area and how partisan it has been.

Because generating tons of volatility is great for hedge funds, and so forth—it is not particularly good for consumers.

EMMA ALBERICI: The competition regulator, the ACCC (Australian Competition and Consumer Commission), called on the Government to underwrite new power plants for businesses who can't get financed, in order to bring electricity prices down.

Now, Senator Matt Canavan, the Minister for Resources, has said that should include coal.

Do the economics of a new coal-fired power station, stack up?

ALEX TURNBULL: Absolutely not.

The reason is, is that coal prices now are high enough that it is very hard for coal to be a competitor.

You cannot buy a tonne of coal for the 2002 price any more easily than you can send your kids to a private school for 2002 school fees anymore.

EMMA ALBERICI: Surely, setting up a new coal fired power station in Australia would keep Australians in jobs in that sector, where they have traditionally been employed at the likes of Hazelwood and Liddell and so on?

ALEX TURNBULL: It would, but would we like jobs somewhere else? Would we like people building wind farms or solar farms?

Is it the Government’s job to choose which jobs they’re going to protect and which ones they won’t?

I mean, how did that work out for Australian car workers?

At some point, we've got to decide whether we want to invest in things which have a brighter future and a longer-term prospect, or we can try to turn back the tide and fight forces beyond our control.

EMMA ALBERICI: New Prime Minister Scott Morrison, in appointing Angus Taylor as the new Energy Minister, said Mr Taylor would be the minister for reliability in getting energy prices down.

ALEX TURNBULL: I think there is a mistaken idea that there is a conflict between de-carbonisation and reducing power prices.

Renewables are the cheapest incremental source of power.

If firmed well with hydro projects, they are unquestionably the lowest-cost way to get more power generation and thus reduce people's power bills.

EMMA ALBERICI: But you added the caveat there about firming, which is essentially about having it available, when you need it—the whole ‘dispatchable’ terminology.

ALEX TURNBULL: Which is why—

EMMA ALBERICI: But that isn't guaranteed at the moment. There's no way to ensure solar and wind are available when we need it.

Isn't that the problem?

ALEX TURNBULL: There is, if you have enough hydro-capacity.

So in most states, like Queensland and New South Wales, you'd have so low renewables penetration, it has no impact on reliability.

In places like South Australia, of course, they are looking at improved transmission, more (inaudible) cycles, as you get to high levels of penetration.

But this is not something which we don't know how solve. It's just you need to build the hydro-capacity.

EMMA ALBERICI: There are certainly coal miners in Queensland that like—that would like—that would welcome positive government approaches to coal-fired power generation.

Hancock Coal is certainly pushing the point that they ‘remine in the Galilee Basin will create 20,000 jobs and spur growth in the region.

Is the argument—the debate about coal-fired power station—being muddied by the interests of coal miners in this country?

ALEX TURNBULL: I think you would be very hard to conclude that it was not.

There are plenty of large government projects you could do to create a ton of jobs.

But the singular fixation upon those particular assets in the Galilee Basin leads me to believe that there are other forces at work here.

EMMA ALBERICI: What do you mean?

ALEX TURNBULL: That there is an undue level of influence on Liberal Party policy by a very small group of miners—who have some assets they probably now regret having purchased, which did not make a lot of sense anymore—and are trying to engineer an outcome which makes those projects economic.

EMMA ALBERICI: Who are these people that you say have undue influence?

ALEX TURNBULL: (Laughs)

People who own a lot of coal in the Galilee Basin.

EMMA ALBERICI: Alex Turnbull there, an investment banker and the former prime minister's son.