The EnBW subsidiary Netze BW has tested in the E-Mobility-Allee project how the charging of electric cars affects the power grid – and after 18 months has a positive result. When it comes to the idea of nationwide electromobility, there are frequent concerns that charging a large number of electric vehicles could overload the power grid. The EnBW subsidiary Netze BW is now investigating the effects of the charging behavior of electric vehicle users on the local power grid in the project E-Mobility-Allee. The project should also show how network operators can counteract when the grid comes to its limits.
The good news: The blackout did not happen. The 18-month test has rather shown that the network load was less than feared, as Netze BW reported. It was interesting, for example, that the charging behavior of the participants changed significantly in the course of the test. They loaded much less frequently after the initial phase. Apparently, they had gained confidence in the range of electric cars, the test leaders concluded. In fact, during the entire time never more than half of the used electric cars were plugged in – and that only in 0.1 percent of the time. According to Netze BW, 70 percent of the time was not charged at all. “The often expressed fear that all e-cars load after work at the same time and thus overload the network, does not seem to be realistic after this experience,” said project manager Selma Lossau.
Lossau sees great potential in so-called intelligent charging management. In the test about bottlenecks were avoided by the electronic allocation of the loading times. The participants felt that they had not been affected, said the project manager. Also useful are different types of battery storage. These were temporarily used in the project and relieved the network. A total of ten households took part in the E-Mobility-Allee project in the town of Ostfildern, south-east of Stuttgart, in the state of Baden-Württemberg. These were supplied with various electric cars – VW E-Golf, Renault Zoe, BMW i3 and Tesla Model S – and the necessary charging infrastructure. The e-car quota reached thereby 50 percent, all households hung on the same circuit. In the coming weeks, further projects will be launched to test the grid load caused by e-mobility, including in a large residential complex in the Ludwigsburg area and in a rural area.