Ostfildern is 20 minutes from the major city of Stuttgart. At first glance, Belchenstraße in the Ruit district looks just like many other residential streets in Germany. The single-family homes and plots are neither particularly large nor particularly small, there isn't anything flashy about the architecture and the cars are neatly parked. Yet a closer look reveals something surprising: five of the eight cars parked along the 100 metre long road are electric vehicles and two charging stations have been installed in the cul-de-sac. In fact, the inconspicuous looking Belchenstraße has been transformed into “E-Mobility Avenue” in the last few months.
Since June 2018, Netze BW has been testing the impact of electromobility on the electricity grid in a pilot project being conducted in cooperation with the City of Ostfildern. They are investigating what would happen if lots of residents on the same street, who are supplied with energy via the same electricity circuit, decide to switch over to electric cars at the same time, and how the use of battery storage systems may increase the stability of the grid.
To gain some insight into how charging patterns can be managed in a way that is customer-friendly but also has no negative impact on the grid, Netze BW has equipped ten households in Belchenstraße with e-cars and the corresponding infrastructure for charging them at home for a period of 12 months. The cost of the field test has proved worthwhile. Ultimately, the goal is to make the electricity grids fit for the age of electromobility. The location for the trial project has been well chosen. The households participating in the trial are representative of a typical residential area with owner-occupied homes, as is often found on the outskirts of cities. An area where in all probability most electric cars will be found in future. The mix of residents is also ideal: Belchenstraße is home to families with children, young couples and retired people – people with different lifestyles and different user patterns.
One of the residents and participants in the project is Norbert Frank, who is self-employed and a family man. “I was curious to see what it would be like to test an electric car on a daily basis over a long period of time,” explains Frank, describing his reason for participating in the project. “Although we already have two cars, we thought it would be a useful addition, especially for journeys of up to 40 or 50 kilometres. These are the distances covered every day by my wife in particular. She is the one that uses the E-Golf provided by Netze BW the most.” What has the experience been like so far? “Extremely positive,” says Frank. “Everything works fine – both driving and charging – and we haven’t noticed any bottlenecks in the electricity grid.”
However, the e-mobility tester has noticed that the cars consume significantly more electricity in the cold winter months. “We are only able to cover about half the distance in winter as in the summer with the same amount of charge. “When we unplug the car from the socket in the morning, it displays a range of 246 kilometres. If my wife drives to Reutlingen and back, which is around 75 kilometres, the display then only shows 92 kilometres remaining. It still showed 150 or 160 kilometres in the summer. That means we have to charge the vehicle every day in winter.” The main cause of the higher energy consumption is the heating in the car, which uses a lot of energy at lower temperatures.
Yet even charging the car daily isn't a complicated process for the Frank family. A compact rectangular charging station that takes up very little room has been fitted to the wall in the garage, a so-called wallbox. This is where the e-car is recharged with electricity, generally in the evening or overnight, as Frank explains. “We usually charge the car in the evening between 7 o’clock and 10 o’clock or at night between 10 o’clock in the evening and 6 o’clock in the morning.”
It takes around 3 to 5 hours until the batteries in the E-Golf are fully charged again. “Sometimes it takes a little longer, depending on the load placed on the electricity grid,” says Christian Bott, who is responsible at Netze BW for the pilot project in Belchenstraße. “The challenge is to minimise peak loads while fully exploiting the capabilities of the electricity grid.” Something that is necessary when several residents in Belchenstraße charge their e-cars at the same time. The charging capacity can then be reduced temporarily from 22 kilowatts to 11 kilowatts and the charging time increases accordingly. This “smart charging management system” takes into account the charging status and predicted departure time for each e-car. “The process is automatically managed overnight so that users do not notice whether their car was charging from the grid for 3, 5 or 8 hours.”
The convenience of charging at home is an important reason as to why Norbert Frank is likely to continue using an e-car after the end of the trial project. “I can certainly highly recommend using an e-vehicle, especially for short journeys,” confirms Frank. But the situation is a little different for longer journeys. “I often have to drive to Frankfurt or Cologne for business and that would still be a little problematic with an e-car. The infrastructure and charging capacities would still need to improve.” Norbert Simianer, a neighbour from across the road, has a similar opinion on the matter. “Electromobility is perfect for short trips but everything has to be very well planned in advance for longer journeys,” explains the pensioner, who was the resident in Belchenstraße who submitted the application to participate in the pilot project for Netze BW. “I have been driving a hybrid car for some time and really wanted to know what it would be like to drive a purely electric car.” The test vehicle being used by Simianer is a Renault Zoe. His verdict: “The Zoe is very suitable for everyday life. I use it just like I use my own car.”
And that’s why the former school principal has also used his electric car for longer journeys. “We have already taken trips to Lake Constance and Switzerland. It was necessary to search for suitable charging stations there in advance because every provider has their own system, but even this issue can be overcome.” He certainly didn't find himself stranded without power. To provide Norbert Simianer with a home charging solution he can rely on at all times, Netze BW have also fitted a battery storage system next to the wallbox in his garage. “There were some special factors that needed to be considered in this case,” explains Netze BW expert Bott. “From an electricity grid perspective, Mr Simianer lives right at the end of the electricity line on Belchenstraße. He also drives an e-car with a high charging capacity of 22 kilowatts. To take these circumstances into account, we charge the Zoe from a separate battery storage system to reduce the load on the grid.” And this storage system is in turn charged at times of the day when other electric cars are not connected to the electricity grid. This delicate balancing act is carried out silently in the background, unnoticed by the customer.
No wonder then that the e-pioneers Frank and Simianer don’t focus too much on the electricity supplier and grid operator when they describe the challenges that need to be overcome in order for electromobility to finally make a breakthrough. “The car industry also needs to play its part,” says businessman Frank. “The choice of e-cars that have a good range is still very limited.” As a frequent driver, he would also like to see more charging stations and above all shorter charging times when on longer journeys. “When it takes more than 1 hour to charge my car with electricity at a service station, I end up drinking a lot of coffee.” “In particular, we need uniform standards for the entire charging infrastructure”, adds Simianer. “Nobody takes 20 different adapters with them when they go on a trip.” And the e-pioneer wants to say something else before he jumps in his Zoe to make his next (short) trip: “The electricity used to charge the electric car should preferably be green electricity. But then EnBW does already offer the right mix.”
Interview with Monika Bader, Senior Planning Officer for Ostfildern
Electromobility is an important element of the new mobility concept that we are currently developing. The challenge is to intelligently network all types of mobility – in terms of both private and public transport.
Firstly, the project is helping to improve acceptance and enthusiasm for electromobility amongst the general public. People can see that the technology really works. They can also gain a better understanding of all the things you need, such as charging stations and additional electricity storage systems – and the fact that you might need to plan your journeys a little better than before.
Yes, and this is a real challenge because of the limited space. There is actually no space left available in public areas. The options are extremely limited, especially in existing urban districts.
Specific mobility concepts are already taken into account when developing the first concepts for an urban development project, even as early as the competitive tendering process. We are already thinking about future requirements – such as central intermodal hubs and parking guidance systems – and take into account the space needed for charging stations, as well as for external electricity storage systems and substations. The project in Belchenstraße has already clearly demonstrated that electromobility requires a highly efficient electricity grid.
That's correct. Digitalisation means that we will have to supply many more computers with electricity. When planning urban developments that are fit for the future, we also have to consider that people’s homes and places of work will move much closer together. We will need to provide the right infrastructure and this means that when we talk about the expansion of broadband, we are also talking about the expansion of the electricity grid.
The ideal companies should provide a highly efficient electricity grid that is supplied with a very high proportion of renewable energies. A grid that will be able to cope reliably with the high demands of electromobility and digitalisation at all times. EnBW and Netze BW are making really good progress in this respect, boosted by the research projects they are running in our community.
“Enthusiasm for electromobility is growing.”