ACT Minister for Transport Chris Steel plugs a bus in to charge at the new Woden Bus Depot. Photo: Ian Bushnell.
Installing EV chargers in bus depots can drive up demand on the local electricity grid by up to 17 per cent in summer and by up to 30 per cent during the evening peak, according to the University of NSW (UNSW) Energy Institute.
The institute reported the findings in its submission to the NSW Parliament’s ongoing inquiry into `Infrastructure for electric and alternative energy source vehicles in NSW’, tasked with looking at what the state needed to grow its EV fleet.
The researchers praised the local government for its efforts in trying to drive down emissions from heavy vehicles such as buses and trucks, which make up 38 per cent of Australia’s total transport emissions despite making up only four per cent of the national transport fleet.
NSW is on a mission to add EV charging to 11 bus depots across the state to support its goal for 1700 electric buses by 2028 under a Zero Emissions Buses Program.
But UNSW cautioned that unless these changes came with “complementary infrastructure” including solar panels, batteries and local grid upgrades, they risked driving up electricity prices for other residences or businesses in the area.
“Electrifying a bus depot in NSW without flexibility measures could increase the summer peak demand by up to 17 per cent at the local zone substation and increase the evening peak by between 20-30 per cent,” the submission read.
NSW wants to add 1700 electric buses to its fleet by 2028. Photo: Transport for NSW.
This comes at the same time the state government is trying to “lower the cost of electricity and reduce the risk of power outages in NSW” with its Peak Demand Reduction Scheme, according to the NSW Government website.
Over the border, the ACT Government has paid local utility company Evoenergy $26.3 million over the past three years to power up its new Woden bus depot and upgraded Tuggeranong bus depot.
A total of 11.9 km of new high-voltage cable has been laid between the Wannisassa Zone Substation and Woden, providing capacity to charge up to 100 buses, and Tuggeranong with capacity for up to 200 buses.
But this is where the ACT Government argues the costs will stop.
“Electricity network tariffs across ACT customers are regulated by the Australian Energy Regulator,” a government spokesperson said.
“These network tariffs typically reduce with greater network utilisation, as the fixed costs of operating the network are spread across more kilowatt hours.”
In effect, this means electrifying two of Canberra’s bus depots “has not increased electricity costs”.
“The infrastructure is funded by the requesting customer and the costs are not shared across other Evoenergy customers.”
One of Evoenergy’s Canberra substations. Photo: Evoenergy.
UNSW’s submission also stressed the importance of using existing electrical infrastructure as a “crucial” way to keep costs down for consumers and suggested kerbside charging should be “ubiquitous at every point of public and ideally private parking”.
“If this can be achieved, the electricity grid will be able to take advantage of the load and potentially generation flexibility of every parked car,” the submission read.
“This would help alleviate the potential issue of EV charging exacerbating network issues related to both minimum and peak demand as vehicle to grid (V2G) technology evolves.”
The ACT is investigating rolling out an example of this, in the form of streetlight chargers.
In 2024, the government connected a designated EV charger to a streetlight pole near 37 Eastlake Parade in Kingston, an area chosen for having residential and commercial traders nearby.
The trial looked at how much power was drawn from the local electrical network whenever a car was plugged in to charge, especially as most existing streetlight poles aren’t supplied with electricity during the day.
The spokesperson said the government was still “working closely” with local electricity provider Evoenergy on the results of the trial and a report would be completed later this year.
The streetlight EV charger on Eastlake Parade, Kingston. Photo: James Coleman.
“The power draw from the electrical network is a critical element that will need to be considered to determine the viability of a larger rollout of this technology,” the spokesperson said.
“Other EV charging sites on streetlight poles across the ACT will be considered following the outcomes of the trial.”
More than 250 EV public charging bays, including in excess of 100 fast (direct current) plugs and 150 slower (alternating current) plugs, currently operate in the ACT.
“There are fast DC and slower AC chargers available in every urban zone and more chargers are on the way over the next 18 months to fill the remaining gaps in the charging network,” the spokesperson said.
A full map of chargers and their locations are available on the PlugShare app or website.
