When it’s parked in your garage, the Polestar 3 can now help you save on your electric bill.
The automaker is the latest to roll out bidirectional charging for its electric vehicles, making it possible to charge the SUV’s battery when power is cheap and then use the vehicle to power your house when prices go up. The company partnered with Dcbel, a startup that makes technology that manages the flow of energy between the car and home.
“Most of our cars sit in driveways more than 80% of the time,” says Dcbel CEO Marc-André Forget. “Now, for the first time, if we think about it, cars start to be useful even when parked. This is transformational. It’s the second-largest investment for most family after the market of the home, and those assets are underused.”
When you plug the car into Dcbel’s home energy station, called the Ara, artificial intelligence kicks in and analyzes energy prices, forecasts how much energy you’ll need over the next few days and how much you need for driving, and, if you have solar panels, it also predicts how much solar power you’ll be generating.
The device uses that data to decide, “Should I charge the car right now?” Forget says. “Should I supercharge the car? Should I wait and charge later? Should I use the energy from the car to power the house, to basically avoid buying energy from the grid at a very high price?”
When your house needs power, the equipment converts DC power from your car into AC for the wiring in your home. (The tech can also double as an inverter for solar panels, though if you already have a solar inverter, it likely doesn’t have the right software to work with an EV.)
Any EV could become bidirectional, but automakers need to develop software to make it work. Polestar spent 18 months working with Dcbel to design a seamless user experience. Users can track the system through an app, though it handles everything automatically. If the power goes out in the middle of the night, the car will wake up and start charging your house. If the grid is down over a long period, the car’s battery can charge an average house for 2.5 days, or as long as 10 days if you start rationing power.
The home energy system is pricey, starting at $5,000 for a base model. But in California, Dcbel won a grant that will provide customers with generous rebates: up to $8,100 for a full-featured version of the tech, up to $2,000 for installation, up to $200 for interconnecting to the grid, $1,000 to enroll in a dynamic rate utility program, and up to $2,500 toward a bidirectional EV like the Polestar 3. The rebates are first-come, first-serve, and decline over time. But for the first customers, the charging equipment could be nearly free.
“We chose to focus on California primarily because of the state incentives that are available,” says Peter Wexler, head of product for Polestar in North America. “They made a natural introductory plan for us.” Customers in other states can buy Dcbel’s charging system, but would have to front the full cost.
For utilities, this type of system can help stabilize the grid. Power demand surges at certain times—when everyone gets home from work in the evening, or when everyone turns on their AC during a heat wave. If enough EV owners use their batteries to power their house when demand is highest, it can make it possible for utilities to avoid turning to more polluting sources like gas power plants.
California also has some vehicle-to-grid (V2G) pilots that allow EV owners to sell power back to the grid at peak hours and make money, but that isn’t yet widely available since the public utility commission still needs to finalize interconnection and compensation rules. Dcbel’s equipment will enable V2G charging as soon as utilities permit it.
Dcbel has developed and shared a new software standard for bidirectional charging that it hopes automakers will universally adopt; it’s currently working with eight automakers to add other cars to its system. Forget contends that more cars with this capability will likely roll out soon, noting, “I think we’re going to see lots of news about current cars becoming bidirectional over the next couple of months.”