The expansion of public charging infrastructure in Germany is increasingly running into invisible barriers. While automakers are continuously bringing new models with higher charging capacities on the market, the commissioning of new HPC (High-Power Charging) charging stations along highways and in urban areas is being delayed with increasing frequency. The reason is rarely a lack of charging stations, but rather the lengthy approval processes and capacity limits of regional distribution grids.
To overcome this bottleneck, the industry is seeking alternatives. One is becoming increasingly prominent: battery-buffered charging. By using stationary battery storage systems directly at the charging station, the peak power required for ultra-fast charging can be provided locally without the need for an expensive and time-consuming expansion of the grid connection. The principle is based on a continuous, grid-friendly V1G smart charging process. That is an intelligently controlled, unidirectional charging process in which the storage system is charged at low power and then, when needed, delivers maximum currents to the vehicles on an as-needed basis.
The scale of grid expansion at the low- and medium-voltage levels is immense. Scientific studies, including those by the German Energy Agency (dena) and the Fraunhofer Institute for Systems and Innovation Research (ISI), estimate the investment required to upgrade distribution grids over the coming decades at high double-digit billions. A large portion of these costs is attributable to covering peak loads, such as those caused by the uncontrolled, simultaneous charging of multiple electric vehicles at highway interchange points.
A typical fast-charging station with six 300-kW charging points requires a theoretical peak power of 1.8 megawatts (MW). If a new power line must be build to the nearest substation to accommodate this, costs can quickly reach the six-figure range per location, accompanied by approval processes that often take 18 to 24 months. If an operator instead opts for a battery-buffered system with an integrated 500-kWh storage unit, an existing standard commercial connection of 150 kW is often entirely sufficient. The economic benefits of this smart-charging approach are immediately measurable:
A look at the practices of charging park providers like JOLT Energy demonstrates just how efficiently this decoupling from the physical grid works. The company installs ultra-fast charging stations in urban centers and at high-traffic intersections, which are internally buffered by high-capacity batteries.
To illustrate the economic relevance in day-to-day operations, it is worth looking at the annual provisioning costs (power price). Grid operators charge significant fees for providing peak power. If a charging park is operated uncontrollably and registers a peak load of 1,500 kW, this results in grid costs alone of around 150,000 euros, based on an example capacity price of 100 euros per kW per year.
With intelligent V1G charging management and a buffer battery, the grid draw for the entire station is strictly capped at, for example, 200 kW (peak shaving). The remaining energy demand during peak hours is supplied from the stationary storage system. This can reduce the annual grid costs for power provision to 20,000 euros. This corresponds to a direct operational savings of 130,000 euros per year per location.
Battery-supported smart charging shifts the challenges of the mobility transition from physical copper lines to intelligent software control. Of course, buffer batteries are not a cure-all: manufacturing the storage systems requires resources, and systemic conversion losses occur when energy is stored and discharged. Nevertheless, the practice of infrastructure development clearly shows that decoupling grid capacity from charging power is the fastest way to drive widespread HPC expansion.