EV Charging at Home in Australia
There are only about 3,000 public EV charging points in Australia.
For every 300 vehicles on the road, one is electric. It doesn’t seem like a lot, but the rate will accelerate as time goes on. Other countries are seeing major upswings in EV uptake which means a lot of people are doing their EV charging at home.
Which begs the question, is the Australian electricity grid ready for EV home charging?
There is an unfounded assumption that the demand on the electricity grid by many users charging their EVs at the same time will place the system under pressure.
According to case studies compiled by the Electric Vehicle Council, the expected impact of EV charging at times of peak demand will top out at about 250W per EV under the ‘convenience model.’ This ‘convenience model’ assumes there are no tariffs controlling or incentivising when to charge – drivers will simply charge when it’s most convenient.
This is half as much as a small, refrigerated air conditioner (500w) and a quarter of some higher-end desktop computers, assuming 80 per cent plus efficiency (700-1000W). With computers being used during the day by people who work from home this represents a significant cost over EVs.
The University of Queensland undertook a study of 239 Tesla vehicles over a six-month period, showing the impact per EV at peak times is within the 150-300W range.
Typically, one kW of charge adds one kilometre of range to an EV every 10 minutes. Put simply, a 10kW charger will give a vehicle 60km of range after charging for an hour. At present, most home chargers are limited to 4.8-7.6kW (20A-32A @ 240V, single phase, depending on location).
Detailed modelling by the CSIRO says that 250W per EV is about a fifth of the impact forecast under the convenience model. However, the convenience model does not line up with real-world behaviour, as most drivers would charge their vehicles at a charging station during the day (as they’re on the road) and at home at night-time.
The University of Melbourne predicts that 250W per EV is one eighth of the impact forecast under the convenience model. This assumes 80 per cent of drivers will use the 7kW chargers at home, with a typical 2kW excess on the grid during peak times on weekdays.
Most drivers are willing to avoid peak time charging, as it costs less. The EVC and Tesla Owner’s Club of Australia ran a survey in 2022 which showed a majority of Tesla owners charged during the nightly off-peak of 12am-2am, and the middle of the day (10am-2pm) when solar production is at its best.
Although Australian electric vehicles (EVs) sales lag behind the rest of the world (1.6 per cent compared with a global average of 4.6 per cent) the CSIRO forecasts that won’t last forever. In fact, if we follow the “current trajectory” of EV uptake, incentivisation, and charging station development, short-range EVs will reach price parity with similarly classed Internal Combustion Engine (ICE) vehicles.
There are only about 3,000 public EV charging points in Australia. This comprises AC “trickle” charging, with 291 rapid (above 50kW) charging stations and 1,580 regular (below 50kW) charging stations available around the country. About 700 more fast and “ultra-rapid” stations (300kW+) are planned for development within the next five years.