EVs could cut household power costs, reduce need for home batteries – study

Electric vehicles equipped with vehicle-to-home (V2H) technology could significantly reduce household electricity costs and lessen the need for large home battery systems, according to new Australian research.

The study by Flinders University, University of Adelaide and Murdoch University examined how using an EV as a mobile energy storage unit affects the optimal sizing of rooftop solar and battery systems in grid-connected homes.

Researchers analysed three residential energy setups: solar, battery and EV with V2H; solar and EV; and EV only.

Under the most efficient configuration — combining solar, battery and V2H-enabled EV — a 7kW solar system paired with a 9kWh home battery delivered the lowest annual electricity cost of $2451.

Electricity costs fell to 27c/kWh and grid imports dropped by 78% compared with a home without solar or battery.

Lead researcher Golsa Azarbakhsh says the findings highlight the expanding role of EVs beyond transport.

“Our work shows that enabling electric vehicles with V2H technology can play an important role in supporting renewable energy use in homes,” Azarbakhsh says.

“Vehicle-to-home capability can reduce the need for dedicated home battery storage while lowering household electricity costs by about 6.8%.”

When V2H capability was not used, the study found a larger 13kWh home battery was required to achieve similar performance, increasing annual electricity costs by 10.8%.

Co-researcher Solmaz Kahourzade says the results are particularly relevant in Australia’s energy landscape.

“South Australia already has some of the highest rooftop solar uptake in the world, but many households still depend heavily on the grid during peak times,” Kahourzade says.

“If we want to accelerate electrification and reduce energy bills at the same time, V2H is one of the strongest tools available.”

The study used real electricity tariffs, weather data and household energy profiles from Adelaide, factoring in variables such as EV usage patterns and battery charge levels, as well as South Australia’s 1.5kW export limit for residential solar systems.

Researchers say V2H improved solar self-consumption and reduced reliance on the grid, particularly during winter when solar generation is lower.

“With EV adoption rising and more households investing in rooftop solar, V2H technology could soon become a mainstream tool for managing energy costs,” Azarbakhsh says.

The findings were presented at the Australasian Universities Power Engineering Conference.