‘Battery on wheels’: Sweden powers homes with EVs
Hudiksvall, SWEDEN—When they get home, the residents of a small housing association on the outskirts of Hudiksvall, Sweden, plug in their electric vehicles (EVs) to charge them or, intriguingly, power their homes.
The two-way energy exchange enables the eight families living there to save a lot on electricity bills, resident Filip Kiltorp, a 33-year-old salesman, told Agence France-Presse (AFP).
“We use the cars to power our homes when our energy demand is high,” he said, standing next to his electric vehicle.
The cars are connected to charging points by the garages for the flats, which are in traditional red buildings bordered by birch trees and a large golf course.
Electric vehicles, when not in use, often have surplus energy stored in their batteries.
But having a bidirectional charger means this stored energy can be fed back into the grid to power the flats’ electrical appliances, lighting and other systems.
The software controlling the system ensures that the car batteries charge up in off-peak hours, when demand for electricity in the flats is low.
‘Undeniably cheaper’
And it switches the flow so the batteries feed electricity back into the local power grid during peak usage hours, when electricity from the network is most expensive, and during power outages.
This helps stabilize the grid, explained Klas Boman, the driving force behind the project.
It also lowers the occupants’ electricity bills.
“Living here is undeniably cheaper,” Kiltorp said.
“Electricity costs are a recurring topic of discussion at the office or among friends. We use the same amount of electricity as other homeowners but our bill is much lower,” Kiltorp continued.
The flats are powered by other, renewable energy sources too, making them “almost self sufficient,” Kiltorp said.
No longer simple modes of transport, the cars now also serve as mobile energy storage units.
In addition, the eight flats have a shared heat pump, which helps manage heating costs.
And they have solar panels on the roofs, combined with stationary storage units that hold any surplus power generated by the solar panels.
The pilot project is a joint enterprise by housing association BRF Stenberg, carmaker Volkswagen and Swedish utility company Vattenfall.
‘Source of inspiration’
It aims to demonstrate that V2G (vehicle-to-grid) technology can work on 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 vehicle industry.
In Sweden, the technology is also being tested in larger buildings, universities and startups.
Gavle University in central Sweden staged a power cut in the middle of a speech there by the higher education minister to demonstrate how its bidirectional chargers worked.
They plugged an electric car in and this kept the premises working for several 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 are standing still in a car park somewhere,” he explained.
“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.”
