New research from the University of Michigan, conducted in collaboration with Ford Motor Co., provides one of the most detailed, geographically resolved analyses to date of vehicle-to-home (V2H) energy systems in the United States. The study evaluates how using electric vehicle (EV) batteries to supply household electricity can reduce energy costs and lifecycle emissions under real-world grid and climate conditions.
Published in Nature Energy, the research moves beyond conceptual discussions of V2H by quantifying its performance across diverse regions, accounting for variations in grid emissions intensity, electricity pricing, housing stock, and climate.
Rather than treating V2H as a theoretical capability, the researchers modeled how bidirectional charging would operate in practice using a representative mid-sized electric SUV. The analysis incorporated region-specific grid characteristics, temperature-dependent efficiency effects, and residential electricity demand patterns, all of which influence how and when stored vehicle energy can be dispatched to a home.
To capture these differences at scale, the team divided the contiguous US into 432 regions defined by shared grid conditions and climate profiles. This approach allowed the researchers to identify where V2H operation provides net system benefits and where technical or grid constraints limit its effectiveness.
These maps illustrate median life-cycle greenhouse gas emissions changes across the contiguous US for several EV charging strategies analyzed by University of Michigan and Ford researchers. The scenarios compare emissions impacts from smart charging aligned with low-carbon grid periods, vehicle-to-home (V2H) operation supplying household electricity, and V2H use in fully electrified homes. (Image: Jiahui Chen with data from J. Chen et al. Nature Energy. 2025 (DOI: 10.1038/s41560-025-01894-7)
“We have a lot of geography-based insight,” shared Jiahui Chen, lead author of the study and a doctoral student at the University of Michigan’s School for Environment and Sustainability. Not all regions experienced the same outcomes, but the results showed that V2H-enabled operation produced net greenhouse gas reductions that fully offset charging-related emissions in regions representing roughly 60% of the US population.
The study also examined system-level interactions between bidirectional charging, grid emissions profiles, and time-varying electricity prices. In regions with high peak emissions or large price spreads, optimized charge and discharge timing allowed stored vehicle energy to displace higher-emissions generation during peak demand periods.
“When people think of EV charging, it’s usually thought of as a burden, a cost that is added to your electric bill,” said Chen. “But with this kind of technology integration, we can make charging an asset.”
Quantified system-level impacts
Using the region-specific models, the researchers quantified the economic and emissions impacts of V2H operation. Across the modeled regions, optimized bidirectional charging reduced lifetime EV charging costs by approximately 40% to 90% relative to conventional charging strategies, depending on local grid conditions and electricity pricing.
The analysis also showed that V2H operation reduced lifecycle greenhouse gas emissions associated with household electricity use by roughly 70% to more than 100% in many regions, with some locations exceeding 200%. Reductions above 100% occurred when strategic discharge during high-emissions grid periods more than offset the emissions associated with charging the vehicle for driving.
In absolute terms, this corresponded to tens of metric tons of avoided carbon dioxide emissions over a vehicle’s lifetime.
Engineering considerations and system maturity
Bidirectional home charging enables EV batteries to supply household electricity under grid and climate-dependent conditions. (Image: Ford Motor Company)
While the results demonstrate strong economic and environmental potential, the authors stress that V2H deployment is not yet turnkey in most US markets.
Effective implementation requires bidirectional power electronics, advanced charging controls, and coordination with utility rate structures, interconnection requirements, and local grid constraints.
“Technology to control charging and maximize V2H value isn’t fully plug-and-play in the US yet,” said Hyung Chul Kim, a research scientist at Ford and a co-author of the study. “It’s actively being demonstrated with utilities, and we’re working to identify use cases while also optimizing battery lifetime.”
Battery degradation management remains a key engineering consideration. The study assumes intelligent control strategies that limit unnecessary cycling and prioritize battery health, underscoring the importance of software-driven energy management alongside inverter and power electronics design.
The researchers note that the long-term goal is a system in which drivers do not need to actively manage charging behavior. Instead, background control software would automatically determine optimal charge and discharge windows based on grid conditions, household demand, and vehicle availability.
Implications for EV and grid engineers
For EV engineers, power electronics designers, and grid planners, the study highlights several practical implications:
- EV batteries represent a distributed energy storage resource already deployed at scale.
- Bidirectional charging capability can materially affect grid decarbonization without requiring additional stationary storage.
- Regional grid characteristics strongly influence V2H value, reinforcing the need for location-specific system design and control strategies.
- Battery management systems, inverter design, and utility integration software will play a central role in scaling V2H safely and economically.
“We know that vehicles are parked the vast majority of the time, and as this infrastructure develops, there’s a great opportunity here,” said Robb De Kleine, a life cycle research analyst with Ford and a co-author of the new study.
While that infrastructure begins to scale, the team hopes its collaboration can also lead to a more immediate shift in the way people think about energy and their vehicles.
“Ultimately, the goal is that drivers won’t have to change anything,” said Kim. “They would park and plug in their EVs as normal, then technology running in the background automatically finds the best charging and discharging times.”
The research team also included James Anderson, technical leader for sustainability and environmental science at Ford, and Greg Keoleian, professor at the University of Michigan. A corresponding policy brief was published alongside the study.
Filed Under: Batteries, Charging, FAQs, Vehicle-to-Grid (V2G)