The Coalition was accused of pursuing a "not zero" strategy after its own modelling revealed it would fall 15 per cent short of achieving carbon neutrality without the help of technology which didn't yet exist.

Fiji Prime Minister Frank Bainimarama this week said he found it troubling the Morrison government was relying so heavily on aspirational technologies to cut emissions, given the pressing threat of climate change.

But Dr Finkel, who is now the government's special advisor on low-emissions technologies but was not involved in the modelling, has suggested it would have been "outrageous" not to account for inventions.

"I was stunned to see this allowance [of technology breakthroughs] disparaged by some international and domestic critics," he said in a speech to the State of Energy Research Conference earlier this week.

"What this allowance does is acknowledge the reality that ongoing research, innovation and the expression of human ingenuity over the next 29 years will deliver solutions that we cannot possibly conceive of today, let alone include with precision in a model.

"If, as the critics wanted, the modelling had assumed full knowledge today of everything we will need in order to get to net zero, that would be outrageous."

Meanwhile, a leading progressive think tank has called for governments to stop talking in "hushed tones" about the end of coal after a new report forecast coal-fired power stations would close at a far quicker rate than expected.

The Australian Energy Market Operator on Friday published a roadmap for transforming how the nation would be powered over the next 30 years.

Stakeholders were consulted on four scenarios, with modelling for the option picked as most likely to occur predicting coal-fired powers stations would shut at nearly triple the speed expected.

All coal capacity could close before 2040, the report found.

Under the so-called "step change" scenario, renewables would account for 96 per cent of power generation in two decades' time - up from 28 per cent last financial year.

Richie Merzian, who runs the climate and energy program at The Australia Institute, said the market operator's report provided a blueprint for how the nation could run a coal-free power grid.

Mr Merzian said it was time for federal and state governments to be open about, and start planning for, the retirement of coal-fired power stations.

"It is time to stop talking in hushed tones and behind closed doors about the retirement of coal," he said.

The report also flagged the need for a major investment in transmission infrastructure, and a significant increase in storage and firming capacity to support the massive influx of renewables.

Mr Merzian said Labor's $20 billion plan to modernise the grid should be a priority for whichever party wins next year's election.

Tony Wood, who leads the Grattan Institute's energy and climate change program, said it was imperative market bodies, industry and governments worked together to ensure the grid remained reliable, price shocks were avoided and emissions were reduced amid the transition.

"That's not going to be easy, because this is a once-in-a-100-year-type transition," he said.

"We're going to fundamentally reconfigure a system that was built 100 years ago, in 30 years, and that won't happen without huge amount of coordination and working together."

Ariel Liebman is the chair of Energy Research Institute Council for Australia, which hosted the event Dr Finkel addressed earlier this week.

Professor Liebman likened the scale of technological change required to manage the energy transition to the rapid development of jet aircraft before World War II.

"We know how to do it when we've got a war, now we've got to do it when we've got to do something that actually sustains us all and sustains human civilisation properly," he said.

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