Energy stored in electric car batteries could power your home or stabilise the grid — and save you money

A very well researched piece by James Purtill for Catalyst in ABC Online

Until recently, Gary Hogben did not expect he would ever be paid to simply plug his car into the wall every night.

And yet, over the past year, that’s exactly what’s happened. He and his wife have earned more than $1,000 while their car sits in the driveway.

The service is called V2G, or “vehicle to grid”, and it could be an important component of Australia’s electricity grid in coming years, plus a way for car owners to make a little extra income.

The concept is fairly straightforward: electric vehicles (EVs) are essentially very large batteries on wheels. Most of the time they sit idle.

With V2G, the batteries in parked EVs are hooked up to a special “bi-directional charger” and coordinated through a central server to export power to the grid during periods of high demand (namely, the evenings, when people turn on appliances).

EV owners like Gary are paid for each unit of energy they export. They then recharge their EV batteries overnight, when demand is lower and energy is cheaper.

Under his current tariff, Gary gets about 30 per cent more for each unit of energy he exports than for the unit he imports.

He and his wife trialled V2G to reduce the household’s carbon footprint, but now he’s making bank.

“One EV battery typically contains as much energy as an average household uses over two-to-four days,” Dr Sturmberg said.

“On top of this, it can react to events in a tenth of a second.

“The fact that they’re available to be called upon to provide power at very, very short notice, that’s a really valuable service.”

He said Australia was well placed to take advantage of V2G, due to it being a world leader in rooftop solar.

“Because of that, we have quite a lot of industry engagement from the electricity sector,” he said.

But there’s a long way to go.

The battery technology used in most EVs today, called CCS, is not compatible with V2G.

Of the cars sold in Australia, only the Nissan Leaf ZE1 and Mistubishi Outlander plug-in have V2G charging capability.

But that’s due to change. By 2025, all new EVs will be V2G capable.

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