The German government wants to increase the number of electric vehicles in Germany to 15 million by 2030, which will require huge market growth. In addition to the availability of suitable and affordable e-cars, local charging infrastructure is a particularly important prerequisite for this. Current studies indicate that electric vehicle owners at present usually have access to their own parking space with their own charging facilities. To accelerate the market roll-out, however, action must be taken for the approximately 3.5 million apartment buildings – accounting for about half of all homes in Germany – and the approximately 2 million relevant non-residential buildings such as offices, supermarkets or carparks. A comprehensive transition to electricity-based mobility will only succeed if these buildings are also equipped with the relevant charging infrastructure and if the local electricity networks can take the potential strain due to high charging capacities.

This was the starting point for the joint study by Fraunhofer ISI and ISE, which examines the charging infrastructure potential of apartment and non-residential buildings, the future demand for charging and the extent to which the electricity distribution grids are able to meet this demand. The observations about establishing charging infrastructure in the aforementioned buildings are made with a particular focus on Germany’s Building Electric Mobility Infrastructure Act (GEIG), which is due to be revised following the amendment of the EU Energy Performance of Buildings Directive (EPBD).

What is the demand for charging in apartment houses and non-residential buildings?

The conducted simulations show that, in theory, it would be sufficient to install charging points for 20 percent of the e-vehicles in apartment buildings by 2030 – provided that parking spaces with charging infrastructure are available, these are shared and can be used directly by the next vehicle once charging is complete or fees are charged for blocked parking spaces. However, the study’s authors believe this is neither realistic nor desirable and consider this 20 percent to be the lower limit of demand. For 2030, they assume there will be around 1.6 million private electric vehicles and electric company cars in apartment buildings with private parking spaces. Under the German Building Electric Mobility Infrastructure Act (GEIG), however, there is only an obligation to install charging infrastructure in the event of major renovations and new builds. This is why the study assumes there will be fewer than one million charging points in apartment buildings by 2030. A significant gap will therefore emerge between infrastructure expansion and demand if expansion only takes place in line with the minimum legal requirements. Due to the low renovation rate in Germany, even if a possible GEIG amendment featured more ambitious targets, it would still not be enough to close this gap.

Based on the number of parked electric vehicles, the demand for charging infrastructure is lower for non-residential buildings than for apartment houses. This is due to the fact that many private and company vehicles will be primarily charged at home in the future. It can be at least partially assumed that charging points will be freed up as soon as charging is complete. This means that charging points for 10 percent of the vehicles stopping at non-residential buildings are likely to be sufficient. The calculations in the project show that approximately 3 million vehicles would be charged daily in non-residential buildings, assuming a stock of 15 million electric passenger cars in 2030 and one charge per vehicle and week. These buildings are therefore very important because they offer plannable charging opportunities, especially for the residents of apartment houses who do not have their own parking space or charging infrastructure, and enable solar-powered charging during the day at the same time. Here, an ambitious design of the legal minimum quantities of charging infrastructure could help close the gap for apartment buildings.

With a view to the German Building Electric Mobility Infrastructure Act (GEIG) and the planned amendment of the EU‘s Energy Performance of Buildings Directive (EPBD), study author Dr. Annegret Stephan from Fraunhofer ISI emphasizes: “It should be noted that there is a gap between both the current legal requirements and the future minimum requirements based on the amendment to the EU Directive and the need for charging infrastructure in apartment buildings. A more ambitious design of the future GEIG could reduce this gap and make it much easier for residents to use and charge electric vehicles.”

At present, the GEIG only includes an obligation to install charging infrastructure in the event of major renovations and new builds. This poses problems for people living in existing apartment buildings. “If we only rely on the renovation requirements for existing buildings, private charging infrastructure will be a project that takes a century,“ says Friederike Piper, Policy Officer for E-Mobility and the leader of the study at T&E. The renovation rate in Germany is only about one percent. “Half of all German homes are in apartment buildings. This must be taken into account if the transformation of the mobility sector is to succeed, since electric mobility for the general population is not only about affordable electric cars, but also about affordable charging.”  

What impacts will high charging capacities have on the electricity networks?

The study assumes a significant additional load for low-voltage networks in the future, as study author Dr. Matthias Kühnbach from Fraunhofer ISE emphasizes: “This may make it necessary to expand the grid at places already subject to high loads today. The use of grid-oriented load management could reduce the height and duration of peak loads. As there will still be rapid growth in the electrification of the vehicle stock in 2030, further challenges to the distribution network should be expected for the period after 2030.” The use of energy management systems for private charging appears to make sense, so that preference can be given to electric vehicles that only have a short standing time or have a high, short-term energy demand.