When they return home, residents of a small housing association on the outskirts of Hudiksvall, Sweden, plug in their electric vehicles to charge them or, intriguingly, to power their homes.
The two-way energy exchange enables the eight families living there to save a lot on their electricity bills, resident Filip Kiltorp, a 33-year-old salesman, told AFP.
“We use the cars to power our homes when our energy demand is high,” Kiltorp said, standing next to his electric vehicle.
Cars are connected to the charging points from the garages for the apartments, which are in traditional red buildings bordered by birch trees and a large golf course.
Electric vehicles, when not in use, often have excess energy stored in their batteries.
But having a bi-directional charger means that this stored energy can be fed back into the grid to power home appliances, lighting and other systems.
The software that controls the system ensures that the car’s batteries are charged during off-peak hours, when residential electricity demand is low.
And it switches the flow so that the batteries feed electricity into the local power grid during peak usage hours, when electricity from the grid is more expensive and during power outages.
This helps stabilize the network, explained Klas Boman, the driving force behind the project.
– “Source of inspiration” –
It also lowers residents’ electricity bills.
“Living here is definitely cheaper,” Kiltorp said.
“Electricity costs are a recurring topic of discussion in the office or among friends. We use the same amount of energy as other homeowners, but our bill is much lower,” continued Kiltorp.
The homes are powered by other renewable energy sources as well, making them “almost self-sufficient,” Kiltorp said.
No longer simple modes of transportation, cars now also serve as portable energy storage units.
In addition, the eight apartments have a common heat pump, which helps manage heating costs.
And they have solar panels on the roof, combined with stationary storage units that store any excess energy generated by the solar panels.
The pilot project is a joint venture by housing association BRF Stenberg, car manufacturer Volkswagen and Swedish utility company Vattenfall.
It aims to demonstrate that V2G (Vehicle to Grid) technology can work at the scale of a residential complex.
“We’re trying to be a source of inspiration for others,” said Boman, who used to work in the auto industry.
In Sweden, the technology is also being tested in larger buildings, universities and new businesses.
Gavle University in central Sweden staged a blackout in the middle of a speech there by the higher education minister to demonstrate how its bidirectional chargers worked.
They plugged in an electric machine and it kept the environment running for a few hours.
“I call this a battery on wheels,” Nicholas Etherden, a lecturer and researcher in energy systems at the university, told AFP.
“Cars drive about five percent of the time. Ninety-five percent of the time they sit stationary in a car park somewhere,” he explained.
“If we connect them to the grid, we have a resource that, at any given moment, will provide more electricity than the amount people draw from the grid at peak times.”
– “Great potential” –
On average, a vehicle battery can cover a household’s needs for five to seven days before it dies.
“So we have great potential,” the researcher said.
Wider adoption of the model still faces several obstacles.
It requires a large part of the vehicle fleet to be electric, which is far from the case in Sweden, unlike neighboring Norway and Denmark.
Bureaucracy and a conservative automotive sector are also slowing the large-scale adoption of the technology, even though it has been available for a long time, according to Professor Lina Bertling Tjernberg.
The next big step to speed up its development is to equip every electric vehicle with a bidirectional charging system, said Bertling Tjernberg, who is a professor of power grid technologies at the Royal Institute of Technology in Stockholm.
She complained that the incentives to promote the technology were always changing.
Potential wear on vehicle batteries is also a concern for some.
Bertling Tjernberg said that this aspect needed more research, although experience suggested that batteries last longer than expected.
Etherden, for his part, is convinced that this is not an issue, given the evidence gathered from the past 10-20 years of electric vehicle use.
“The battery will last longer than the car,” he said, adding that powering an average home used the same amount of energy as accelerating from zero to five kilometers (zero to three miles) per hour.
“It’s like riding a donkey. It’s a very careful use of the battery,” he said with a smile.
