Life after death is not only a hope for believers. The second life is also important for electric cars: after several tens of thousands of kilometers, several charges and discharges, the capacity of a battery will ultimately no longer be sufficient to power a vehicle. But especially in combination with other rechargeable batteries, the battery can still serve as storage.
Car manufacturer Ford, Kölner Verkehrs-Betriebe (KVB) and supplier Rheinenergie recently demonstrated it at a terminus of the Cologne tramway. When their cars stop and brake, energy is released that has already been pushed into the grid in the form of a current surge. “No one asked whether we could use electricity or not,” explains Dieter Steinkamp, the boss of Rheinenergie. Instead, hundreds of discarded battery cells now store electricity. The project partners interconnected the modules in a gray house at the edge of the bus stop.
The KVB electric buses are recharged with electricity, which anyway stay a few minutes at the arrival station and unfold their pantographs; it is the name of the pantograph on the roof that we know from trams. The KVB connected a bus charging mast to the new storage facility. Rheinenergie also operates two charging stations for electric cars in the neighboring park-and-ride car park. Since Cologne operates the light rail network with green electricity, the storage system is about green energy, the companies point out.
The Rheinenergie utility wants to use storage to compensate for fluctuations in the electricity grid
The installation, which cost a few million euros and partially funded by the federal government, also aims to avoid voltage fluctuations. Companies fear this could happen without the storage system if a streetcar enters and vehicles are using the fast-charging stations at the same time.
In the pilot plant, Ford is using several high-voltage batteries a second time. They come from electronic models early on, from warranty cases with faulty battery cells, or from vehicles involved in accidents. “It’s a feasible way to recycle batteries in electric vehicles,” says Gunnar Herrmann, director of Ford in Germany. The more electric cars there are on the road, the greater the reuse becomes. Because if you throw away the batteries after their first use in the car, all the raw materials they contain have never been successfully recycled.
The pilot system has worked well so far, says Stefanie Haaks, KVB boss. “You can use it as a blueprint for other purposes and in other places.” Your company has been using the first battery-powered buses since 2016. By 2030, Cologne wants to completely convert the bus fleet to alternative drives. Before the end of this year, according to Haaks, the KVB will put about ten more electric buses into service each month. Cologne is not alone in this case: more and more cities are converting their bus fleets to emit less greenhouse gases and harmful nitrogen oxides and to comply with relevant EU requirements. . In many places, the state subsidizes the purchase of buses and charging stations.
Rheinenergie, in turn, can use the storage facility west of Cologne to compensate for peaks in the regional electricity grid. “We feed when excess electricity is available,” says CEO Steinkamp, and in times of particularly high loads, electricity can be taken out of the system. The more fluctuating wind and solar power enters the grid, the more important these buffers become. “Multiplying this is not just a story for Cologne,” Steinkamp said.