In Menifee, Calif., six newly built homes are testing a first for North America: electric vehicles that can power houses through the Combined Charging System (CCS) high-power DC charging standard. Each home uses a host Kia EV9 electric vehicle connected to a Wallbox Quasar 2 bidirectional charger, allowing the car’s 100-kilowatt-hour (kWh) battery to run essential circuits during blackouts or periods when electricity prices are high. The setup is the first residential vehicle-to-home (V2H) system in the United States that uses the Combined Charging System (CCS) standard. The CCS is the charging system commonly used in European and North American residential and public charging facilities.

Since July, the homes’ smart electrical panels have automatically managed two-way power flow—charging vehicles from the grid or rooftop solar, then reversing the flow of energy when needed. The system isolates each home from the grid during an outage, preventing any current from flowing into external power lines and endangering utility crews and nearby 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.”

Menifee means a lot

For more than a decade, two-way charging has been available—but mostly restricted to Japan. Back in 2012 the Nissan’s LEAF-to-Home program proved the idea viable after the Tōhoku earthquake and tsunami, but that Nissan system relied on the or CHAdeMO standard, little used outside of Japan. Most North American [and European manufacturers chose CCS instead—a standard that, until recently, supported only one-way fast DC charging.

That distinction makes Menifee’s V2H-enabled neighborhood notable: it’s the first CCS-based V2H deployment in occupied homes, giving researchers real-world field data on a technology that’s been long trapped in pilot programs. The pairing of the Kia EV9 SUV with Wallbox’s commercially available Quasar 2 can deliver up to 12 kilowatts of power from the vehicle to the home.

It’s a step toward vehicles that not only move people, but also strengthen the energy system.” –Scott Samuelsen, UC Irvine

Elsewhere, momentum towards commercial V2H has slowed. Ford’s F-150 Lightning supports home backup through Sunrun, but Sunrun equipment is not CCS-compatible. What’s more, Ford has announced a production pause for the pickup truck, which has delayed expansion. GM’s Ultium Home—a V2H system that works with the automaker’s Cadillac Lyriq, Cadillac Escalade IQ, Chevrolet Blazer, Chevrolet Equinox, Chevrolet Silverado, and GMC Sierra EVs— faces similar setbacks. Tesla’s PowerShare V2H feature is still stuck in a limited, early commercial rollout, with bidirectional compatibility restricted to the company’s Cybertruck. Menifee, by contrast, is producing operational data in real households.

Why CCS Matters

When electric vehicles first hit the market, CCS was designed for one job: move power quickly from the grid to the car. The main goal was reliable, standardized, fast charging. That fact helps explain the difference between CCS public chargers, (many of which are rated for 350-kilowatts or more) and their CHAdeMO-based counterparts, which typically max out at 100 kW (but are capable of providing home backup or grid services).

Bidirectional operation wasn’t included in the original CCS standard for several reasons. Early automakers and utilities worried about safety risks, grid interference, and added hardware cost. So CCS’s original communication protocol linking EVs and charging stations—ISO 15118—didn’t even include an electronic handshake for power export. The 2022 update, ISO 15118-20, added secure two-way communication, enabling CCS vehicles to supply energy to buildings and the grid.

Wallbox’s Quasar 2 residential charger implements the update through an active-bridge converter circuit built with silicon-carbide transistors, achieving efficient bidirectional flow. Its 12-kW power rating can support typical critical loads in a house, such as heating and cooling, refrigeration, and networking, says Aleix Maixé Sas, a system electronics architect at Wallbox.

As the company’s name humbly suggests, Wallbox’s chargers look like plain old boxes—although they contain high-tech components.Wallbox

The Menifee blueprint

Each of the Menifee homes outfitted with a V2H system combines a rooftop solar array with a 13-kWh SunVault stationary battery from SunPower. During normal operation, solar energy powers daily household loads and charges the stationary battery. On abundantly sunny days, the solar panels can also top up the Kia EV9’s battery. When the grid fails—or when energy prices spike—the home isolates itself: Solar power and energy stored in the SunVault keep essential systems and appliances going, while the EV battery extends power if the outage persists.

This past summer, the UC Irvine researchers tracked how solar output, stationary storage, and vehicle power interacted under summer demand and wildfire-related grid stress. They found that “the vehicle adds a major resilience feature,” according to Samuelsen, who is the Menifee project manager. “It can relieve grid strain, increase renewable utilization, and lower costs by supplying power during peak-rate hours.”

Engineering the Two-Way Home

Home builders and the makers of electric vehicle service equipment such as Wallbox are not the only entities reconsidering how to meet the engineering demands V2H introduces. Utilities, too, must make changes to accommodate bidirectional power flow. Interconnection procedures and energy pricing structures are among the factors that must be redesigned or reconsidered.

A Glimpse of the Energy Future

Analysts expect double-digit annual growth in bidirectional-charging system sales through the late 2020s as costs fall and standards mature. In regions facing wildfire- or storm-related outages and steep time-of-use pricing curves, projects like Menifee’s are showing a clear path towards the use of cars as huge and flexible energy reserves.

When EV batteries can supply energy for homes as easily as they do for propulsion, the boundary between transportation and energy will begin to disappear—and with it, old concepts regarding who’s an energy supplier and who’s a customer.

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