A new study from the Australian National University reveals that electric vehicles and hot water systems could help transform cities into “giant batteries” by shifting demand and easing pressure on the grid.
Using high-resolution data from the ACT in partnership with Evoenergy, researchers modelled how flexible household energy use could support the energy transition.
They found that EVs and electric hot water systems could provide up to 46 kWh of storage per person—equivalent to around three Tesla Powerwalls.
By simply shifting when we charge cars or heat water, each person could move about 5 kWh of energy use per day to off-peak times.
That’s around one-third of daily per capita electricity use that could be managed to help—not hurt—the grid.
“Cities are often seen as energy-hungry giants ... But with widespread electrification, they could also become giant batteries—managing energy, not just consuming it.”
Dr Bin Lu, Australian National University
The study warns that unmanaged electrification could increase peak demand by more than 30%, pushing grids beyond capacity.
But if just half of the flexible load identified is shifted, that demand spike could be halved—reducing the need for costly grid upgrades.
Researchers say areas with dense populations and concentrated travel patterns—so-called “storage hotspots”—present a major opportunity for smart charging, workplace incentives, and better use of rooftop solar.