Electric car trial tests impact on grid

A fleet of 20 electric cars is being tested in Sydney to help prepare for the possibility of large numbers of the cars plugging into the grid.

The trial is part of the Federal Government’s Smart Grid, Smart City project and involves electronically recording the charging patterns and performance of the cars – Mitsubishi’s iMiEV – to test their impact on the grid.

“We need to look at how and when electric cars will be charged from the grid in the future,” Ausgrid managing director George Maltabarow said.

“If large numbers of motorists charged their cars after work on a very hot or cold evening in a concentrated area, we need to make sure the electricity network will meet that demand.

“It costs about one cent per kilometre to charge an electric car overnight compared to 10c/km to run a petrol car – so more electric cars will be sold in the future and we need to be ready.

“As an electricity network we need to understand the impacts of electric cars on the grid and what the infrastructure needs are.”

The trial will determine a range of factors, including if electricity stored in car batteries could power the grid during times of peak demand; the best locations for charging stations; how to best bill drivers for the power their car uses; car battery performance for different driving conditions – e.g. freeway versus stop start driving; and charging behaviour of drivers – including do they fully charge from empty or top-up regularly each time they stop.

More than 56 charging stations (also called charge spots) are being installed for the trial, including 50 standard charge spots as well as six fast charge spots.

The power socket for the car is 15A and larger than the standard household plug.

Each car is fitted with a GPS and tablet-form data logger to collect real-time information from the vehicle and battery.

Each charge spot is separately metered and monitored in real-time. The standard chargers are centrally controlled and can be managed intelligently to take into account the electricity needs of cars.

The Mitsubishi iMiEV has a 150km range under ideal conditions, although this is affected by highway speeds, number of passengers and the driving terrain.

The car is the first commercially available, fully electric vehicle in Australia and comes with a 47kW permanent magnet synchronous electric motor with 180Nm of torque.