Cars sit still ninety-five percent of the time. That's where the power lives.
In a small housing complex in Hudiksvall, Sweden, eight families have quietly redrawn the boundary between transportation and shelter, using their parked electric vehicles as living batteries that power their homes during the hours when energy costs most. The arrangement, known as Vehicle-to-Grid technology, is less a technological leap than a philosophical one — a recognition that the resources we already possess, sitting idle ninety-five percent of the time, may hold answers to the pressures we have not yet solved. What unfolds in those red-brick flats is a modest but pointed argument that the infrastructure of the future may already be parked in our driveways.
- Eight Swedish families are cutting electricity bills significantly by running their homes on power drawn from their own car batteries during peak demand hours.
- The same technology that lowers individual costs also steadies the broader grid, turning millions of idle vehicles into a distributed energy reserve that could outpace peak national demand.
- A university demonstration made the stakes visceral — mid-speech, the lights went out, a car was plugged in, and the building kept running for hours on battery alone.
- Scaling the system is stalled not by physics but by bureaucracy, low EV adoption rates, and an automotive industry slow to make bidirectional charging standard equipment.
- Battery degradation fears, once a serious objection, are fading — researchers compare the energy draw of powering a home to accelerating a car to walking pace, calling it a gentle use of the technology.
- The path forward depends on policy stability and market persuasion: convincing drivers, developers, and governments that a parked car is also a piece of public energy infrastructure.
In a cluster of red-brick flats on the outskirts of Hudiksvall, eight families have turned their parked electric vehicles into something more than transport. When they plug in at home, power flows both ways — charging the car during cheap, off-peak hours and reversing back into the home when electricity costs peak. During blackouts, the cars become backup generators. Filip Kiltorp, a 33-year-old salesman in one of the flats, put it simply: the bills are lower, and the difference comes up constantly in conversation with friends and colleagues.
The project, called Vehicle-to-Grid or V2G, sits within a broader energy setup that includes rooftop solar panels, stationary battery storage, and a shared heat pump. Klas Boman, the initiative's driving force and a collaboration between housing association BRF Stenberg, Volkswagen, and utility company Vattenfall, described it as a proof of concept meant to inspire others.
Sweden is already testing the idea at larger scales. At Gavle University, researchers staged a pointed demonstration during a ministerial speech — cutting the power mid-address, connecting an electric car, and keeping the building lit for hours. Researcher Nicholas Etherden framed the broader opportunity: cars are driven roughly five percent of the time, leaving their batteries idle and connected to nothing. If linked to the grid, that dormant capacity could exceed national peak demand. A single battery, he noted, can power an average home for five to seven days.
Yet the obstacles are real. Sweden lags behind Norway and Denmark in EV adoption, limiting the available resource. Bureaucratic inertia and a cautious automotive industry have slowed progress despite the technology existing for years. Professor Lina Bertling Tjernberg of the Royal Institute of Technology identified the critical next step: making bidirectional charging standard in every new vehicle, while also calling for more stable government incentives to reduce uncertainty.
Concerns about battery wear appear increasingly unfounded. Etherden compared powering a home from a car battery to accelerating from a standstill to five kilometers per hour — a gentle, almost negligible demand. The real barrier, researchers agree, is not engineering but adoption: persuading a skeptical market that the car sitting in the driveway is already part of the energy grid.
In a cluster of red-brick flats on the outskirts of Hudiksvall, Sweden, eight families have turned their parked cars into something more useful than transportation. When they come home and plug in their electric vehicles, they're not just charging batteries for the next commute—they're feeding power back into their homes, shaving hundreds of kronor off their annual electricity bills in the process.
The system works through bidirectional chargers installed at each garage. An EV sitting idle in a driveway carries surplus energy in its battery, energy that would otherwise sit unused. With the right technology, that stored power can flow backward through the charging point and into the home's electrical system, powering appliances, lights, and heating. The software managing the arrangement is deliberately simple: it charges the cars during off-peak hours when electricity demand in the flats is low and cheap, then reverses the flow during peak usage times when grid electricity costs the most. During blackouts, the cars become backup generators. Filip Kiltorp, a 33-year-old salesman living in one of the flats, described the arrangement plainly. "We use the cars to power our homes when our energy demand is high," he said. "Living here is undeniably cheaper. Electricity costs are a recurring topic of discussion at the office or among friends. We use the same amount of electricity as other home owners but our bill is much lower."
The project is called Vehicle-to-Grid, or V2G, and it does more than lower individual bills. By drawing power from parked cars during peak demand hours, the system helps stabilize the broader electrical grid, reducing strain on centralized power plants. The eight flats are part of a larger energy strategy that includes solar panels on the roofs, stationary battery storage for surplus solar power, and a shared heat pump for managing heating costs. Klas Boman, the driving force behind the initiative, positioned it as a proof of concept. The project is a collaboration between the local housing association BRF Stenberg, Volkswagen, and Swedish utility company Vattenfall. "We're trying to be a source of inspiration for others," Boman said.
Sweden is already testing the technology at larger scales. Gavle University in central Sweden staged a dramatic demonstration during a speech by the higher education minister: they cut the power mid-speech, plugged in an electric car, and kept the building running for several hours on battery alone. Nicholas Etherden, a lecturer and researcher in energy systems at the university, framed the potential in stark terms. "I call this a battery on wheels," he said. "Cars drive about five per cent of the time. Ninety-five per cent of the time, they are standing still in a carpark somewhere. If we connect them to the grid, we have a resource that will, at any given time, provide more electricity than the amount people draw from the grid at the highest peak times." On average, a single vehicle battery can power an average household for between five and seven days before depleting entirely.
But scaling V2G beyond pilot projects faces real obstacles. Sweden has a lower proportion of electric vehicles than neighboring Norway and Denmark, meaning the potential grid resource remains limited. Bureaucratic inertia and a conservative automotive industry have slowed adoption despite the technology being available for years. Lina Bertling Tjernberg, a professor of power grid technologies at the Royal Institute of Technology in Stockholm, identified the next critical step: equipping every new EV with bidirectional charging capability as standard. She also noted that government incentives for the technology keep shifting, creating uncertainty for developers and residents alike.
Concerns about battery degradation persist, though evidence suggests they may be overblown. Bertling Tjernberg acknowledged the question needed more research, but early data indicated batteries were lasting longer than expected. Etherden was more confident. Using battery power to run a home, he explained, demands roughly the same energy as accelerating a car from zero to five kilometers per hour. "It's like driving behind a donkey," he said. "It's a very careful use of the battery." The real constraint, then, is not technology or physics but adoption—convincing a skeptical market that cars parked in driveways can become part of the energy infrastructure itself.
Citas Notables
We use the cars to power our homes when our energy demand is high. Living here is undeniably cheaper.— Filip Kiltorp, resident
Cars drive about five percent of the time. Ninety-five percent of the time they are standing still. If we connect them to the grid, we have a resource that will provide more electricity than people draw at peak times.— Nicholas Etherden, energy systems researcher at Gavle University
La Conversación del Hearth Otra perspectiva de la historia
Why does this matter now, when most people still aren't driving electric cars?
Because the cars that are being sold today will still be here in ten years. Once you have enough EVs on the road, you suddenly have an enormous distributed battery network already in place. You're not building new infrastructure—you're unlocking what's already there.
But won't constantly charging and discharging the batteries wear them out faster?
That's the intuition everyone has, and it's wrong. The researchers I read say powering a home uses about as much energy as accelerating gently from a stop. It's barely stressing the battery. The real wear comes from driving.
So what's actually stopping this from spreading across Sweden right now?
Politics and habit, mostly. The technology works. But you need a critical mass of EVs first, and you need every new car to come with bidirectional chargers as standard. Right now that's not happening. And the government keeps changing the incentives, so nobody wants to invest.
If I lived in one of those eight flats, what would my electricity bill actually look like?
Significantly lower than your neighbors in identical homes. The residents there won't say exact numbers, but they're clear it's a noticeable difference every month. You're essentially using your car as a battery bank when electricity is expensive and charging it when it's cheap.
What happens during a real power outage? Does the car actually keep the lights on?
Yes. They demonstrated it at a university—cut the power in the middle of a speech, plugged in an EV, and the building stayed lit for hours. One battery can run an average home for five to seven days before it's depleted.
So why isn't every housing development doing this?
Because it requires coordination, investment, and a fleet of electric cars that most of Sweden doesn't have yet. It's not a technology problem anymore. It's a scale problem.