The car in your garage can power your house

When there’s a power outage in your neighborhood, the usual response is to fumble around to find a flashlight or matches to light candles. What if you could keep the lights on and power your home merely by connecting your electric vehicle to a wall box in the garage?

For the past several years, sustainable energy researchers at UC Irvine have been working with external partners to make vehicle-to-home charging a commonplace reality. Simply put, V2H allows people to draw power from the battery in their car to run lights, air conditioning and appliances in their homes. It can come in handy during a drop-off in grid-supplied electrical service and can be used by homeowners when utilities charge a higher price for electricity, usually between 4 and 10 p.m.

Roberta Howell is a V2H pioneer. She lives in a comfortable, single-story home on a corner lot in the Shadow Mountain subdivision in Menifee, California. She’s got solar panels on her roof, as does her sister who lives just across the street. KB Home designed and built the community of more than 200 homes from the ground up as a test bed for sustainable energy and microgrid technologies.

“The switch to a fully electric home has been a learning curve for me,” Howell says. “I’m 70 years old and have been using gas my whole life. The induction range cooks very fast, but I was thrown off at first because it didn’t seem to work. My sister said I needed to replace my old pots and pans. You learn something new when you move in here.”

As part of a program to regularize the use of V2H in a residential setting, she’s also learning something new about connectivity between her car and her home. Through a lottery directed by UC Irvine, she became one of half a dozen homeowners in her neighborhood to be issued a new, fully electric Kia EV9 sport utility vehicle. Howell pays the registration fees and insurance, but other than that, it’s basically a free-of-charge lease – thanks to a program managed by UC Irvine, Kia Corp. and Hyundai America Technical Center Inc.

“I love the car and use it a lot more than my other one,” she says of the Kia EV9, which is parked in the garage next to her Lexus SUV. The Kia is on the side closest to the Wallbox V2H bidirectional electric charger. In exchange for the use of the vehicle, Howell shares data generated by the V2H system in her home with researchers in UC Irvine’s Advanced Power and Energy Program.

APEP founding director Scott Samuelsen, professor of mechanical and aerospace engineering, is leading V2H research at UC Irvine and says data acquisition is one of the most important parts of the project. “We are using this information to gain a better understanding of the role of the electric vehicle in the home of the future,” he says. “We’re determined to find out if V2H will provide added value to people going forward.”

Samuelsen shares that data transmissions from Howell’s home in Menifee to his lab on the UC Irvine campus showed that she was not using V2H as intended, at least for the first couple of weeks of the pilot project. According to him, the episode demonstrated that he and his team need to be conscious of the way the user interface to the system is designed so that it’s easy for consumers to operate – or at least that some education and cajoling are occasionally necessary.

How V2H works

Users control the V2H system through an app on their smartphone or computer. They can set it to turn on and off for a specific duration each day. Once Howell got up and running, she scheduled V2H to deliver power from 7 to 10 every evening.

The components of the V2H system include a plug-in electric vehicle and a recently developed technology called “bidirectional electric vehicle supply equipment.” The EVSE is what allows energy to flow from solar panels and the electric utility to charge the car and then, when requested, flow from the car to power the home.

Samuelsen says a key impetus for V2H is the fact that vehicle batteries are about eight times more energy-dense than conventional home batteries. A fully charged, 100-kilowatt-hour EVbattery can power a home for days, while a typical 13-kilowatt-hour home battery can handle two to five hours of usage depending on load requirements in the home. Samuelsen adds that another major V2H benefit is that homeowners can reduce the import of electricity from the utility during the hours of 4 to 9 p.m., when rates are highest.

Samuelsen says he thinks California consumers will grow to appreciate this reliable power source when utilities shut down transmission lines for long periods to prevent the ignition of wildfires. Utilities are willing participants – even though V2H users can save as much as $600 per year in utility costs, according to Samuelsen – because of their interest in innovations that improve the electric grid and their need to prepare for the future to continue receiving certification, support and grants from agencies such as the California Public Utilities Commission.

Utilities also benefit by not having to generate and transmit as much energy during peak evening hours or on hot days when more people are running their air conditioners. Widespread V2H usage could obviate the need for rolling blackouts, Samuelsen says.

The history of V2H

The V2H study got started in earnest in 2020 when UC Irvine engineers reached out to Kia, the Hyundai America Technical Center Inc. and Hyundai Motor Corp. to explore interest in the technology for their plug-in electric vehicles, as well as to Barcelona, Spain-based Wallbox to explore interest in developing a bidirectional EVSE.

“Professor Samuelsen initially contacted Kia about this project, and we immediately answered in the affirmative,” says Steve Kosowski, Kia’s manager of long-range strategy and planning. “Kia had prior history with Professor Samuelsen and UC Irvine on other projects such as the Soul EV and, separately, collaborated on connected and automated vehicle and cooperative driving automation technologies for the Kia EV6.”

Working with Hyundai Motor Corp. in Korea, Kia provided an EV6 all-electric crossover outfitted with prototype V2H software, and Wallbox provided the EVSE – all of which were tested in the APEP Residential Laboratory on the UC Irvine campus under the direction of Samuelsen and his fellow APEP researchers Kate Forrest, Jennifer Lee and Shan Tian.

“Kia’s decision to proceed with V2H was made in 2021 and was driven, in part, by UCI’s bringing Hyundai Motor Group and V2H charger partner Wallbox together – and UC Irvine’s work with the EV6 using third-party software updates to enable V2H,” Kosowski says. This led to Kia’s release of the V2H-ready EV9 for the 2024 model year.

In the fall of 2023, UC Irvine expanded the testing with advanced EVSE prototypes and a prototype EV9 at both the APEP Residential Laboratory and a KB Home model home in Menifee.

In early 2024, UC Irvine began working with Southern California Edison to draft a V2H interconnect agreement, which is required to connect an electricity supplier or generator to the utility grid (as when adding solar panels to a home). In June 2024, the UC Irvine team and Kia delivered EV9s to six homeowners in Menifee and installed Wallbox Level 2 Pulsar Plus chargers in their garages.

In 2025, Wallbox received certification from Underwriters Laboratory for its bidirectional Quasar 2 EVSE, paving the way for commercialization of the technology. The six participating homes in Menifee were equipped with the first commercial Wallbox EVSE units, which required upgrading the homes’ 50-amp charger circuits to 70 amps.

After nearly two years, a V2H interconnect agreement was approved by SCE for the first homeowner. Approval of the “permission to operate” was signed by SCE in May of this year, and the first homeowner began V2H services at the end of that month.

“Through the Menifee V2H project, we found some glaring deficiencies in the timeliness of the interconnection process, as well as with the regulatory bodies’ awareness of the progress of [V2H-like] technology in residential settings,” Kosowski says. “The Menifee project’s successful deployment has corrected many of those deficiencies and has spurred the continued conversation and coordination among Kia, UC Irvine, Wallbox, utilities and other parties to continue to innovate this process to one that customers could reasonably accept to use V2H.”

Samuelsen adds: “Our project has taken several years and has involved a number of technological and regulatory hurdles, but thanks to the cooperation among UC Irvine, Kia, KB Home and Wallbox, we’re in a place now where V2H has a good chance of becoming widely adopted by consumers.”