In short:
As part of a trial, power from electric vehicle batteries in Canberra was fed into the national grid during a major blackout in Victoria.
The batteries provided a small amount of electricity and the trial was deemed a success.
What's next?
Experts say electric vehicle batteries could contribute large amounts of electricity to the grid during times of high demand or power shortfalls.
It was around lunchtime on a day in February this year when a storm tore down power lines west of Melbourne, forcing a power station and a wind farm to shut down and leaving 500,000 Victorian customers without electricity.
The incident also caused instability in the national energy grid, which stretches from Port Arthur in Tasmania to Port Douglas in Queensland, and across to Port Augusta in South Australia.
About 500km away from the downed power lines, in what is believed be a world-first response to a blackout, charging stations began draining the batteries of ACT government electric vehicles in Canberra and feeding the power back into the national grid.
Only 16 electric cars out of a fleet of 51 involved in the Realising Electric Vehicle-to-Grid Services project were hooked up to the chargers, which was never going to produce enough power to bring many lights back on in Victoria.
But Bjorn Sturmberg, a senior research fellow in battery storage and grid integration at the Australian National University, believes it was an important demonstration of how electric vehicles can help boost the national electricity grid during times of high demand, or outages.
"We had a fleet of 51 electric vehicles, which is no match for the largest coal generator in Victoria,'' Dr Sturmberg said.
"Of those [16 vehicles] that were connected, they responded exactly as they were intended to and they provided a bit over 100 kilowatts of power back into the grid, which contributed to rebalancing the supply and demand in the national grid.''
EVs could power NSW and ACT
Dr Sturmberg said if the 100,000 electric vehicles sold in Australia last year could feed power back into the national grid when needed, they would provide about the same amount of power as used by NSW and the ACT.
And while many electric vehicle batteries can't currently discharge electricity into the grid, simply stopping them from charging for a short period of time during an emergency could help keep electricity on.
"That could be something that could be implemented today," Dr Sturmberg said.
"It could be something that auto manufacturers just send out, a signal to all of their vehicles saying 'Whoa, we've got a once-in-five-year kind of event, let's just stop charging for half an hour and then you can go back to what you were doing'."
Energy providers already have agreements with some big power users, such as factories and large commercial enterprises, to slow down or stop operations during times of extreme demand on the grid.
ACT Energy and Emissions Reduction Minister Shane Rattenbury said vehicle-to-grid technology could play a pivotal role in the transition from fossil fuels to 100 per cent renewable energy in Australia.
"What it did demonstrate — we believe for the first time in the world — is that electric vehicles can be used in the kind of way that they can respond to a shortage in the grid, be switched on almost intravenously to start providing back into the grid,'' Mr Rattenbury said.
"If you think about the number of cars in Australia, If you actually start to roll that out on a big scale, it could provide a very powerful response in an emergency situation.''
Drivers can choose not to participate
Electric Vehicle Council energy and infrastructure head Ross De Rango said vehicle-to-grid technology was a huge opportunity for Australia which could put downward pressure on power bills and help enable coal and gas-fired power stations to be closed sooner.
"We'll be able to meet significant amounts of energy system peak demand from our cars, rather than from burning fossil fuels, and then recharge them later on from excess wind or solar,'' he said.
Mr De Rango said it should be up to consumers to decide whether they participated in vehicle-to-grid schemes.
"We don't see a future where anyone is able to draw energy out of a consumer's car without their consent. This level of consumer protection is actually baked in at a very basic level – because it's the driver that decides if the car is plugged in or not,'' he said.
Mr De Rango said it was possible that electric car batteries would lose capacity slighter faster if they were used to feed power into the grid.
Warranty conditions would set out whether specific electric vehicles could be used in vehicle-to-grid schemes.