Bi-Directional Charging News From Kia & Mercedes

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Last week, I was having a conversation with friends who are thinking about installing a backup generator for their home. They were somewhat taken aback by the cost, which in their case included burying a 500-gallon propane tank in the backyard, pouring a concrete pad for the generator to sit on, and an electrician to upgrade their electrical panel. All in all, it came to a big number. I asked them if they had considered purchasing an electric car with bi-directional charging capability, especially if they paired it with a solar array so they could charge the car with renewable power and have access to electricity during an extended outage. The idea had never occurred to them, but they quickly realized it could save them money every month while it met their basic needs for electricity when there was no power available from the grid. They had never considered owning an electric car before, but suddenly they started seeing things in a whole new light.

Bi-directional charging is the future. It will make residential backup generators obsolete, it will promote more rooftop solar, and it will become a vital component of virtual power plants and distributed renewables that will incorporate demand response into policies and procedures that help manage power grids more efficiently so we can avoid building new thermal generating stations that add more pollution to the atmosphere. And here’s something else to consider. Bi-directional charging isn’t free but it is an investment, one that can pay for itself over time. There are both tangible and intangible benefits. It is easy to put a value on the kilowatt-hours of electricity that go into and out of the battery of an electric car, but what is it worth to have a week’s worth of electricity sitting in your driveway when you need it and all your neighbors’ houses are dark?

Kia Adds Bi-Directional Charging To EV9

Wallbox this week began pre-sales of its Quasar 2 bi-directional charger for the Kia EV9 in the US, which will enable customers to use the electric SUV as an energy storage unit. The vehicle to home service will initially be available in California, Washington, New York, Florida, Texas, New Jersey, and Illinois. “A nationwide rollout will follow,” Kia said in a press release on March 4, 2025 Kia. The Quasar 2 offers up to 12 kW of power for EV charging and discharging. Together with the corresponding Power Recovery Unit, it will be available for $6,440.

“We’re thrilled to open pre-order availability of the innovative Quasar 2 charger, including the Power Recovery Unit, to eligible Kia EV9 drivers,” said Enric Asunción, CEO of Wallbox. “This cutting-edge technology allows eligible EV9 owners and lessees to take control of their energy usage and costs, while also providing backup power during power outages.” The program is a little late getting started. The Quasar 2 was initially supposed to be available in the first half of 2024.

Mercedes Promotes Vehicle-To-Grid Technology

There are three kinds of bi-directional charging. Vehicle-to-load allows the battery in an EV to run power tools or small appliances in remote locations. Vehicle-to-home, such as what Wallbox and Kia are doing, lets the battery power the normal loads associated with a residence — things like heat pumps, lights, televisions, internet routers, and the like. Vehicle-to-grid connects the car’s battery to the local utility grid. By so doing, the battery becomes part of a virtual power plant, accepting excess electricity when supplies are high and sending electricity back to the grid when supplies are low. Utility companies compensate those who provide such demand response services, which can help offset the cost of buying an EV that supports V2G technology.

Leading up to the Special Exhibit Bi-directional Charging event at Power2Drive in Munich in May, Frank Spennemann, the senior manager for charging solutions energy at Mercedes Benz, talked to Electrive [see video below] about his company’s approach to vehicle-to-grid technology and the challenges that must be overcome. One of the key questions in the industry is whether AC or DC will dominate bi-directional charging. “That’s a question which probably will be answered in the next five to ten years,” Spennemann said. While both technologies exist, he observed most automakers are starting with DC, as it is technically easier to integrate with the grid. “If you feed into the grid, you have to comply with so-called grid codes, which are defined by the grid operator. With DC, the wallbox must meet these grid codes, whereas with AC, compliance is split between the car and the wallbox, making it more complex.” That is why he expects DC to dominate in the initial phase.

“We are absolutely convinced that bi-directional charging only makes sense if it’s interoperable. It has to be based on a standard,” he states. The company’s next generation of EVs will fully integrate bidirectional capabilities, providing customers with new ways to interact with the grid. We intend to introduce it with the next generations of our vehicles, and you will see it when they hit the market,” he said. “A standard European household consumes around 10 kWh of energy per day. Our EQS, with a 110 kWh battery, could power a home for more than a week during a power outage,” Spennemann said. Additionally, bi-directional charging can help EV owners maximize the use of their solar panels. “People with PV installations want to be self-sufficient. A bidirectional car, ideally combined with a small home storage system, allows them to store solar energy during the day and use it at night.”

Beyond energy security, V2G technology can create new revenue streams. “The energy grid desperately needs flexibility and is willing to pay for it. In Germany, for example, the total maximum power load is around 70 to 80 gigawatts. That equals 7 million cars connected — about 15% of the passenger car fleet. This is real power,” Spennemann stated. According to his estimates, EV owners could earn between €400 and €700 per year by feeding energy back into the grid. “The exact amount depends on the vehicle, charging behavior and other factors, but the potential is significant.” He added that integrating cars with bi-directional capability into the grid is essential for achieving renewable energy goals. “All research institute simulations rely on bi-directional cars playing a role in stabilizing the grid and supporting the energy transition.”

Regulatory Hurdles

Despite the technological progress and its many advantages, bi-directional charging faces regulatory challenges, especially in Germany. “The biggest issue is double taxation,” Spennemann said. At the present time, when energy is stored in a vehicle and later fed back into the grid, it is taxed twice, which significantly reduces its monetary value. “With these levies, the customer won’t see any value. And if there’s no financial benefit, there’s no motivation to invest in a bi-directional wallbox.” He added, “The cars are coming, the standards are there, and implementation is underway.” But for bi-directional charging to become mainstream, industry players and policymakers must work together to remove barriers and unlock its full potential. As the EV revolution accelerates, the ability to use vehicles as dynamic energy assets could redefine the relationship between mobility and electricity, Spennemann said at the conclusion of the interview with Electrive.

There are a lot of things that need to happen before bi-directional charging goes mainstream and people start making money by sharing the batteries in their electric cars with utility companies, but as the notion of virtual power plants and microgrids gains acceptance with utility companies and customers, it will become commonplace. When will that be? Not this year, but by 2030 might be a reasonable guess. It is just one more reason why electric cars are the future and combustion engine cars are the past.