By David Sullivan, former Head of Electrification business for ABB in Australia.
Worldwide sales of EVs have crossed the four million mark. It is estimated that by 2027-28, about 650,000 EVs will be operational on Australia’s roads.
However, with memories of the state-wide blackout in South Australia in September 2016 still fresh, there is genuine concern if the existing power grid will be able to support the increased demand from the new EVs about to hit the streets.
Before we get into the details, it’s helpful to first understand the challenges to the grid due to a high number of EVs, which mainly involves low voltage electricity distribution network. With most plug-in electric vehicle drivers doing more than 80 percent of their charging at home, most of the grid infrastructure that we see around us every day, such as residential power lines and pole-mounted transformers, ends up handling the majority of extra load.
In an unregulated environment, most EV owners are likely to plug in and begin charging the moment they return home from work, which is the time residential electricity networks experience peak demand. This can lead to network failures and overload, substantially shortening of lifetimes of grid components.
The good news is that all these problems can be prevented by implementing a smart charging framework and shifting EV demand away from the peak hours.
EVs are among the most flexible loads in the grid, unlike lighting or heating our homes, so we can easily shift the demand to other times, like overnight, when the network is under less pressure. Residential chargers can fully charge EVs in around six to eight hours, meaning users can put their car on charging before going to bed and find it fully charged in the morning. Furthermore, a standard commute leaves enough spare battery capacity to allow the car to make an emergency late-night run, even if it is not fully charged.
Setting up a residential charging system is not difficult or expensive. Compact chargers, like ABB’s TerraAC Wallbox, provides a high quality, yet cost effective EV charging point at homes or small businesses. An ideal scenario would be that each home with an EV acquires a home charging terminal, which receives instructions from the utility operator via a household smart metre. This will allow the operator to control vehicle charging across the network, based on existing network conditions and demand.
Extensive modelling and simulations, based on real Australian data, have shown that the network that started to fail at a 10 percent EV uptake with uncontrolled charging is able to sustain more than an 80 percent uptake when the timing of vehicle charging is changed, using simple optimisation algorithms.
Moreover, parking and driving behaviors show that Australians are better suited to EVs, with two out of three cars parked in owner-occupied garages, allowing for consumer-installed re-charging infrastructure.
By ensuring proper demand management to charge EVs through a smart grid, most of our existing networks should be able to sustain high uptake rates, without much additional investment into infrastructure for decades to come.
