New research from the Australian National University (ANU) indicates that electric vehicles (EVs) and household hot water systems could help transform cities into large-scale energy storage systems, thereby enhancing the electricity grid. The study reveals that by optimizing the charging and heating times, urban areas like Canberra could utilize these technologies to shift from energy consumers to energy providers. Residents could collectively manage significant energy storage capacity, improving grid stability and supporting the integration of renewable energy sources, ultimately leading to reduced greenhouse gas emissions.
The research suggests that in a fully electrified city, the collective energy storage capacity could yield each individual access to around 46 kilowatt-hours (kWh), which is comparable to owning three to four Tesla Powerwall batteries. By strategically staggering when EVs are charged and hot water systems are heated, communities can ease pressure on the electricity grid, particularly during peak demand times. The team asserts that shifting just half of this load to off-peak hours could reduce peak demand pressures significantly, allowing for better utilization of rooftop solar energy.
As transport and heating account for a large portion of greenhouse gas emissions—over 12 billion tonnes reported in 2019—transitioning these sectors to rely on electricity sourced from clean energy is essential for emissions reduction. The market for EVs and heat pumps is expanding, with over 17 million electric vehicles sold in 2024, while heat pump capacity reached 1,000 GW by 2021. This shift towards electric systems provides opportunities for distributed energy storage (DES), which utilizes car batteries and hot water tanks to smooth out energy consumption patterns.
Although there have been various small-scale studies on energy management, comprehensive city-wide DES models remain rare. The ANU study emphasizes the importance of large-scale modeling to plan future energy systems effectively, control costs, and facilitate cleaner urban environments as cities aim for full electrification. The research utilizes the Australian Capital Territory (ACT) as a case study, which is notable for its commitment to renewable energy and aspirations for net-zero emissions by 2045.
By employing detailed mapping tools to analyze energy usage on an hourly and neighborhood basis, the study seeks to identify locations where demand shifts can occur, ultimately paving the way for a more resilient and adaptable energy grid. The findings indicate that if residents intelligently shifted the timing of EV charging and hot water heating, they could collectively manage around five kWh of electricity in off-peak hours, signifying a notable opportunity to bolster energy supply during peak consumption.
EVs, which are typically parked and unused for most of the day, have great potential to contribute to this energy management framework, especially when combined with efficient charging strategies. However, neglecting this coordination could result in a spike in peak electricity demand by over 30%, leading to costly infrastructure upgrades. Therefore, strategically shifting loads is crucial, as even a modest reduction could halve the peak demand increase and optimize rooftop solar energy use, particularly in the evenings.
Additionally, the study identifies urban “storage hotspots” characterized by high employment density and flexible energy demand scalability. These areas present opportunities for enhanced workplace charging strategies, dynamic energy pricing, and coordinated control through digital technologies. The research results were published in the journal Renewable Energy, marking a significant advance in understanding how urban energy systems can evolve in a sustainable manner.