If cars become batteries on wheels, cities become power plants

While our collective eyeballs were fixed on the US election last week, you may have missed a milestone in the energy revolution.

On Saturday, Energy Minister Chris Bowen announced a development that will transform the way energy is produced and consumed in Australia: vehicle-to-grid charging is here.

Vehicle-to-grid charging could be a gamechanger for the electricity system.Credit: Getty Images

That means if you own an electric vehicle, you will soon be able to use it as a giant household battery. Or as Bowen put it: “No longer will charging be a one-way street. You can charge when you want to charge and you can discharge back to your house or to the grid when that suits you.”

Standards Australia has ticked off the standard that will allow vehicle-to-grid charging in Australia, and Bowen is encouraging manufacturers of vehicles and charging infrastructure to apply to the Clean Energy Council for product approval. Companies such as Germany-based Ambibox are already gearing up.

Bowen was speaking to attendees at an electric vehicle trade show in Sydney, and his announcement was previewed in Drive, a sister publication to this masthead. But the news is significant for all Australians, even those of us who are not car heads.

Nearly 4 million Australian households have rooftop solar panels, the latest figures from SunWiz show, and more than 300,000 have household batteries.

The volume of solar power being pumped into the grid makes batteries an important piece of the puzzle. The problem is that the energy is being produced in the middle of the day when few consumers need it. Electricity demand peaks in the evening, when the sun goes down.

This means a demand curve known as the “solar duck” because of its shape.

A battery flips that on its head. The battery can charge during the day when there is plentiful solar energy and then households can use it when they need it, or they can sell it back to the grid if their retailer allows it. The household pays less for electricity, the grid is more stable, and non-solar households also get cheaper power because networks don’t have to produce as much expensive peak-time energy. Win, win, win.

That’s why governments are now incentivising households to install batteries. The NSW government battery rebate scheme began on the first of this month, for example.

You can buy an electric vehicle for about $40,000 and the battery inside is three or four times larger than a typical household storage system. The equivalent home battery would probably cost about the same, but without the bonus of a car.

It’s possible that vehicle-to-grid charging could even be worthwhile for households without solar, as they could take advantage of off-peak rates. And they’ll still have a car, even if retailers adjust their prices.

An electric vehicle that can discharge to your home or the grid whenever you want is a battery on wheels. An entire city full of rooftop solar and electric vehicles is a power plant. The notion of traditional “baseload power” becomes redundant.