Cars sit idle 95 percent of the time. That's a resource.
In a small housing complex on the edge of Hudiksvall, Sweden, eight families have quietly redrawn the boundary between transportation and energy infrastructure. By connecting their electric vehicles to bidirectional chargers, they have transformed idle machines into living batteries — drawing cheap power at night, returning it during costly peak hours, and in doing so, glimpsing a future where the car in the driveway is as much a utility as the wires in the wall. The experiment, modest in scale, carries an outsized question: what becomes possible when millions of parked vehicles are no longer passive, but participants in the grid?
- Eight households in central Sweden are already paying significantly less for electricity by letting their cars act as home power banks during peak demand hours.
- The technology has existed for years, yet bureaucratic inertia, scarce bidirectional chargers, and Sweden's slower EV adoption rate have kept it from spreading beyond a handful of pilots.
- Concerns about battery degradation linger in the public imagination, though researchers argue the energy drawn for a typical household day is barely the equivalent of accelerating to a slow crawl.
- A university in Gävle made the stakes vivid by cutting power mid-ministerial speech and letting a single plugged-in EV keep the auditorium running for hours — a demonstration as theatrical as it was technical.
- The project's architects see one clear unlock: making bidirectional charging standard on every new electric vehicle, turning a niche pilot into a continent-scale grid stabilizer.
On the outskirts of Hudiksvall, eight families have quietly redefined what a car is for. When they return home and plug in beside their red-painted garages, they are not simply recharging — they are connecting to a two-way energy system that draws power from their vehicles' batteries to run their homes during peak hours, or feeds surplus electricity back into the local grid when prices spike.
Filip Kiltorp, a salesman living in the complex, describes the logic simply: the cars power the flats when electricity is expensive. Software charges the batteries overnight, when grid power is cheap, then reverses the flow during peak demand. The result is a household that consumes the same electricity as its neighbors but pays considerably less.
The project — a collaboration between housing association BRF Stenberg, Volkswagen, and utility Vattenfall — layers Vehicle-to-Grid (V2G) technology onto solar panels, stationary battery storage, and a shared heat pump, making the complex nearly self-sufficient. Architect Klas Boman, a former automotive industry veteran, hopes it will serve as a replicable model.
Researchers elsewhere in Sweden are amplifying the message. At Gävle University, a lecturer named Nicholas Etherden staged a pointed demonstration: mid-speech by the higher education minister, the building's power was cut, an EV was plugged in, and the car kept the auditorium running for hours. Etherden notes that cars sit idle roughly 95 percent of the time, and that a single battery can cover a household's electricity needs for five to seven days. "We have enormous potential," he said.
Yet the path to scale is uneven. Sweden trails Norway and Denmark in EV adoption, bidirectional chargers remain rare as standard equipment, and government incentives have been inconsistent. Battery wear is a concern, though Etherden argues the energy used to power a home for a day is roughly equivalent to accelerating a car to five kilometers per hour — negligible wear for a battery he believes will outlast the vehicle itself.
For now, Hudiksvall remains a proof of concept: eight families showing that the cars in their driveways are not just personal transport, but small distributed power plants, steadying the grid while quietly shrinking their own bills.
On the outskirts of Hudiksvall, in central Sweden, eight families have turned their electric vehicles into something more than transportation. When they arrive home and plug in at the charging stations beside their garages—traditional red buildings ringed by birch trees and overlooking a golf course—they're not just refueling. They're tapping into a two-way energy system that lets them draw power from their cars' batteries to run their homes, or feed surplus electricity back into the local grid when demand spikes and prices climb.
Filip Kiltorp, a 33-year-old salesman living in the complex, describes the arrangement plainly: the cars power the flats when electricity demand peaks. The software managing the system is elegant in its logic. It charges the vehicle batteries during off-peak hours, when the building's power consumption is low and grid electricity is cheap. Then, during peak usage times—when grid power becomes expensive—or during outages, the system reverses the flow, pulling stored energy from the cars' batteries to supply the homes' appliances, lighting, and heating systems. The result is tangible. Kiltorp notes that his household uses the same amount of electricity as other homeowners but pays significantly less. "Living here is undeniably cheaper," he said.
The project, a collaboration between the housing association BRF Stenberg, Volkswagen, and Swedish utility Vattenfall, demonstrates what Vehicle-to-Grid (V2G) technology can accomplish at residential scale. But the eight flats are not relying on EVs alone. Solar panels on the roofs feed into stationary battery storage units that hold surplus power. A shared heat pump manages heating costs across all units. Together, these systems make the complex nearly self-sufficient—a working model that Klas Boman, the project's architect and former automotive industry veteran, hopes will inspire others.
Sweden is already testing the concept elsewhere. Gavle University in central Sweden staged a dramatic demonstration: during a speech by the higher education minister, the university cut the power to the auditorium, then plugged in an electric vehicle connected to a bidirectional charger. The car kept the building running for several hours. Nicholas Etherden, a lecturer and researcher in energy systems at the university, frames the potential starkly. "I call this a battery on wheels," he said. Cars sit idle roughly 95 percent of the time, he noted, parked in lots and garages. When connected to the grid, that dormant capacity becomes a resource. On average, a single vehicle battery can cover a household's electricity needs for five to seven days before depleting. "So we have enormous potential," Etherden said.
Yet scaling the technology faces real obstacles. Sweden lags behind neighboring Norway and Denmark in EV adoption—the technology only works if enough vehicles on the road are electric. Bureaucratic inertia and a conservative automotive industry have slowed deployment despite the technology being available for years, according to Lina Bertling Tjernberg, a professor of power grid technologies at the Royal Institute of Technology in Stockholm. She points to inconsistent government incentives and the lack of bidirectional chargers as standard equipment on new vehicles. Battery wear is another concern some raise, though Bertling Tjernberg suggests the evidence is reassuring and more research is needed. Etherden is more confident, noting that powering an average home consumes roughly the same energy as accelerating a car from zero to five kilometers per hour—what he calls "driving behind a donkey." The battery, he argues, will outlast the car itself.
The next acceleration point, Bertling Tjernberg argues, is equipping every new electric vehicle with bidirectional charging capability as standard. Until then, the Hudiksvall complex remains a proof of concept: eight families demonstrating that the cars in their driveways are not just personal transport, but distributed power plants, stabilizing the grid while lowering their own bills.
Citas Notables
We use the cars to power our homes when our energy demand is high.— Filip Kiltorp, resident
Cars drive about five percent of the time. Ninety-five percent of the time they are standing still in a car park somewhere.— Nicholas Etherden, energy systems researcher
La Conversación del Hearth Otra perspectiva de la historia
Why does a housing complex in Sweden matter for the rest of us?
Because it shows that the infrastructure we're already building—electric vehicles—can do double duty. Most people think of an EV as a car that charges at night. This project says: what if that car also powers your home during expensive peak hours? It's a shift in how we think about energy storage.
But isn't this just a nice experiment for eight wealthy families?
It could be. But the researchers are testing it at universities and larger buildings too. The real constraint isn't the technology—it's that Sweden doesn't have enough electric vehicles yet. In Norway, this would scale faster. Here, it's a chicken-and-egg problem.
What about the batteries wearing out?
That's the honest concern. But the researchers who've studied this for years say powering a home uses almost no battery capacity compared to driving. One researcher compared it to accelerating very slowly. The battery will likely outlive the car.
So what's actually stopping this from happening everywhere?
Three things: not enough EVs on the road, government incentives that keep changing, and car manufacturers haven't made bidirectional chargers standard. It's available technology, but the system hasn't aligned yet.
If it works, why isn't every new car sold with this capability?
That's the question the researchers are asking too. The technology exists. The economics work. But the automotive industry moves slowly, and regulations haven't mandated it. It's bureaucracy and inertia, not physics.