People arriving home from work plug their electric vehicles into the power socket to sell the battery's remaining charge back into the grid. They can make a bit of money and help lighten the load on the network during the 6pm cooking peak.

Their car's battery is then recharged in the wee hours, when grid demand - and prices - are at the lowest ebb.

It is a future that is looking increasingly likely, according to experts, and one that presents unique challenges to the people running the nation's energy systems.

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And Australia's smallest state may have a big role to play in the solution.

"Australia is experiencing a complex, rapid and irreversible energy transformation," says Daniel Westerman, CEO of the Australian Energy Market Operator.

His organisation, which manages the country's vast electricity and gas systems, has just released a 30-year roadmap detailing the investments needed to keep the lights on through what is expected to be a most tumultuous period of transition from coal-based to renewable generation.

Based on one of AEMO's "most likely" predicted future scenarios, Mr Westerman believes demand for electricity in Australia "will double by 2050, as transport, heating, cooking and industrial processes are electrified".

This surge in demand will come right as coal generation - which accounts for about two-thirds of output in the national electricity market at present - is phased out by the 2050s.

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In fact, last month, the market gave us a small glimpse of the chaos possible when things don't go to plan.

Scheduled maintenance and plant breakdowns cut a quarter of the country's coal-fired power generation in May-June, just as a cold snap sapped output from solar and wind generators and caused frost-bitten Australians to turn heaters to full blast.

The result was a surge in prices on the national electricity market.

AEMO finally stepped in and suspended the national electricity market to head off the risk of blackouts.

The immediate crisis has now abated, but it demonstrates the importance of securing reliable renewable energy generation during the transition away from coal.

Mr Westerman says what is needed is massive investment in wind, solar, battery and pumped hydro storage, as well as more regular hydro and gas-powered generation.

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Plus, the transmission infrastructure to connect generators with consumers.

That is where Tasmania steps in.

The state's Marinus Link - the project to construct two 750 megawatt-capacity undersea cables across Bass Strait - was one of five energy projects that AEMO in its roadmap this week insisted should be progressed "as urgently as possible".

The $3.8 billion project is managed by Tasnetworks and championed by the state government, as well as some of the most power-consumptive industries in the state.

Chief executive of the Bell Bay Advanced Manufacturing Zone, Susie Bower, says Marinus could help to attract more industries to Tasmania.

"From a development point of view, if we want all of those [industries] in Tasmania, then Marinus is a no-brainer - we have to go ahead with it," she says.

Hydro Tasmania is similarly in favour. If the link is given the go-ahead, the generator plans to redevelop and expand its existing Tarraleah hydro power plant, as well as begin developing a 750MW pumped storage hydro plant at Lake Cethana.

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It says it will also build wind farms in the North-West as well as associated transmission infrastructure.

A spokesperson for Hydro tells The Examiner that Marinus would provide Australians with reliable and cheaper power by "unlocking Tasmania's abundant, low-cost wind resources and pumped hydro storage".

It would also "support lower wholesale energy prices in Tasmania".

But not everybody was as supportive of the project.

Marc White, principal consultant at Goanna Energy, was sceptical over assurances that Marinus would not affect Tasmanian energy prices.

"Hydro claims that Tasmanian consumers won't pay higher prices as a result of Marinus. Our question would be how can they say that when the funding arrangements aren't even agreed?"

Ray Mostogl, CEO of the Tasmanian Minerals, Manufacturing and Energy Council, says while he does not oppose the project, he has some concerns about some of its aspects.

"Marinus is obviously one of the most attractive options available today", he says.

His main reservations are how Marinus would be funded, and where the additional infrastructure needed for Hydro to fully utilise the link would be placed.

"What, if any, costs will Tasmanians bear on behalf of the eastern states? Will the "rules" permit Hydro Tasmania's generation increase upgrades to be funded by the increased revenue they will achieve due to Tasmanian power prices increasing?", he asks.

"Will the hundreds of kilometres of new transmission lines and towers needed to connect new wind farms with the Burnie substation be added to the bills of Tasmanian's or will the "rules" be changed to also fund this under the "Marinus" banner?

Mr Mosotgl says he believes more clarity will come once the funding model for Marinus is worked out in the next few years.

A rule change which is being prepared for consideration will ask for the beneficiaries of Marinus to pay on a proportional basis, he says.

If a state derives 90 per cent of the benefit from the project, then that state should pay 90 per cent of the cost, he says.

A separate funding option is Federal Labor's $20 billion Rewiring the Nation project, Mr Mostogl says.

As a result of Federal Labor's support for Marinus, the project's prospects of progressing have risen sharply since May.

New Federal Energy Minister, Chris Bowen, has said he held "very constructive" talks about progressing Marinus using the funds earmarked for the Rewiring the Nation.

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