Electric Vehicles Power Homes in Landmark US Test,Ushering in New Era of Grid Resilience
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A groundbreaking pilot program in Menifee,California,is demonstrating the potential of electric vehicles to not only transport people but also to power homes,marking a significant step toward a more resilient and lasting energy future. Six newly built homes are currently testing a first-of-it’s-kind residential vehicle-to-home (V2H) system in North America, utilizing the Combined Charging System (CCS) high-power DC charging standard.
The Menifee Experiment: Cars as Power Reserves
As July, these homes have been equipped with a host Kia EV9 electric vehicle connected to a Wallbox Quasar 2 bidirectional charger. This setup allows the car’s considerable 100-kilowatt-hour (kWh) battery to run essential household circuits during power outages or when electricity prices surge. The system intelligently manages two-way power flow, charging vehicles from the grid or rooftop solar and reversing the flow when needed. Crucially, the system isolates each home from the grid during an outage, safeguarding utility crews and equipment.
“This project is demonstrating that bidirectional charging with CCS can work in occupied homes,” says Scott Samuelsen, founding director of the Advanced power and Energy Program (APEP) at the University of California, irvine, which is monitoring the two-year trial.”It’s a step toward vehicles that not only move people but also strengthen the energy system.”
From Japan to North America: A History of V2H Technology
The concept of two-way charging isn’t new. Japan pioneered the technology over a decade ago, with Nissan’s LEAF-to-Home program proving its viability following the 2012 Tōhoku earthquake and tsunami.However, widespread adoption in North America has been hampered by a lack of standardized communication protocols and limited vehicle availability.
The CCS standard, while capable of providing home backup, typically maxes out at 100 kW.
Bidirectional operation wasn’t part of the original CCS standard due to concerns about safety, grid stability, and cost. The original communication protocol, ISO 15118, lacked the necessary “electronic handshake” for exporting power. The 2022 update, ISO 15118-20, addressed this by adding secure two-way communication, enabling CCS vehicles to supply energy to buildings and the grid.
Wallbox’s quasar 2 charger utilizes an active-bridge converter circuit with silicon-carbide transistors to achieve efficient bidirectional flow, delivering a 12-kW power rating sufficient for essential household loads like heating, cooling, and refrigeration.
The Menifee Blueprint: Integrated Energy Management
Each of the Menifee homes integrates a rooftop solar array with a 13-kWh SunVault stationary battery from SunPower. During normal operation, solar energy powers the home and charges the stationary battery.Excess solar energy tops up the Kia EV9’s battery on sunny days.During grid outages or peak energy prices, the home isolates itself, relying on solar power, the SunVault battery, and, if needed, the EV battery to maintain power.
Researchers at UC Irvine tracked the interplay between solar output, stationary storage, and vehicle power during the summer, noting that “the vehicle adds a major resilience feature,” according to Samuelsen, the project manager. “It can relieve grid strain, increase renewable utilization, and lower costs by supplying power during peak-rate hours.”
Engineering a two-Way Grid
The shift to V2H technology requires more than just advancements in vehicle and charger technology. Utilities must adapt interconnection procedures and energy pricing structures to accommodate bidirectional power flow.
Analysts predict substantial growth in bidirectional-charging system sales throughout the late 2020s as costs decrease and standards mature. In regions prone to outages and with dynamic time-of-use pricing,projects like Menifee’s demonstrate the potential of EVs as large,flexible energy reserves.
As electric vehicle batteries become capable of powering homes as easily as propelling vehicles, the lines between transportation and energy will blur, redefining the roles of energy suppliers and consumers.
