A key sales pitch by the board is the estimate, revealed this week, that the scheme will cut households' power bills by an average $150 a year - as part of $550 in overall savings - during the first decade of its operation, starting from 2020.

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"Where is the modelling that proves this?" Mark Butler, federal Labor's climate spokesman said. "All modelling of the NEG should be made available so stakeholders and the public can properly assess its merits."

Josh Frydenberg, federal Environment and Energy Minister, declined to comment on any modelling release, but said: “The National Energy Guarantee will deliver a more affordable and reliable energy system. Modelling undertaken by the independent experts from the Energy Security Board shows households will be $550 a year better off under the Guarantee compared to today.”

A board spokeswoman said the body "is yet to publish the final detailed design [of the plan]," but had "real confidence that the design can deliver on the objectives of affordable, reliable and clean power for Australian households and businesses".

Liberal-led NSW is not among those pressing for additional data.

"The modelling is an internal matter of the Energy Security Board," a spokesman for Don Harwin, NSW's Energy Minister, said.

Bruce Mountain, director of the Victoria Energy Policy Centre - set up recently by that state's Labor government - said the guarantee's projected cost savings were difficult to understand.

Since the emissions target of the plan - cutting 2005-level carbon pollution in the electricity sector by 2030 - will be achieved almost as soon as the scheme begins, the driver of falling prices was unclear, he said.

"How can a policy that is designed to do something that will happen anyway cause prices to be any lower than they would be anyway?" Mr Mountain said, adding that since state governments would sign off on the plan, they should be asked to demonstrate the savings were real.

Dylan McConnell, an energy expert at Melbourne University, noted assumptions contained in the version of the plan leaked to the public this week were at odds with those formally released a week earlier by the Australian Energy Market Operator in its Integrated System Plan.

For instance, the market operator included in its base case the state-run renewable energy plans for Victoria and Queensland. They would help lift clean energy's share of the electricity sector to 46 per cent by 2030 - not far shy of federal Labor's pledge of 50 per cent.

That additional generation, however, is absent in the board's modelling even though the market operator is one of its members and the Victorian target is legislated.

Similarly at odds is the board's modelling that assumes the multibillion-dollar Snowy 2.0 pumped hydro scheme - a key Turnbull government proposal - will go ahead while the market operator does not have project in its base scenario, Mr McConnell said.

The board's modelling "is certainly not consistent" with the market operator's, he said.