The installation of efficient charging technology for electric vehicles in the underground car park of apartment buildings, commercial properties or at the employer's is currently of interest to many landlords and entrepreneurs. The installation of charging infrastructure for residents, customers and employees is currently being carried out in underground car parks in many places or is being planned. For these applications, the installation of a conductor rail system, which allows the flexible and simple installation of wallboxes in underground garages, is particularly well suited. Find out about the advantages of a busbar in underground garages and how to obtain subsidies for your planned installation of charging infrastructure in our blog article.
WHAT ARE THE ADVANTAGES OF INSTALLING CHARGING TECHNOLOGY IN THE UNDERGROUND CAR PARK?
Electromobility is receiving more and more attention and also monetary attention. This also applies to private charging infrastructure. From 24.11.2020, the installation of private charging points can now also be subsidised. But not only the subsidy is an attractive reason for charging infrastructure in the underground car park. Your property will be generally upgraded and you will make it future-oriented and safe.
WHAT IS THE BEST AND STANDARDISED WAY TO INSTALL CHARGING TECHNOLOGY IN THE UNDERGROUND CAR PARK?
Probably the most important point and also the absolutely necessary first step is to apply for the required charging power BEFORE installing the charging technology! The desired charging power must always be reported to your grid operator. From a power of 12 kVA (kilovolt amperes), your grid operator must first approve it. For this purpose, the grid operator will check your request individually and, if necessary, make you an offer for upgrading your grid connection. At DREWAG NETZ GmbH, this is done, for example, by the electrical contractor submittingthe application for grid connection (electricity) and the corresponding data sheet to thegrid operator.
BUT WHAT LEVEL OF CHARGING POWER MAKES SENSE?
DREWAG NETZ provides information on which charging power is worthwhile for your needs.
| NUMBER OF E-PARKING SPACES | RECOMMENDED MAX. CONNECTED LOAD FOR CHARGING DEVICES |
|---|---|
| 1 | 11 kW |
| 2 to 3 | 22 kW |
| 4 to 5 | 33 kW* |
| 6 to 10 | 44 kW* |
| 11 to 15 | 55 kW* |
| 16 to 20 | 66 kW* |
| from 21 | Coordination with grid operator |
* Load management required
This recommendation is based on two important principles. Firstly, a simultaneity of 1 is not assumed when using the charging points. This means that, as a rule, all charging points are never used at the same time and the connected electric vehicles are never all fully discharged - because only then do they claim their maximum charging power. And secondly, from a larger number of wallboxes, the grid operator can prescribe the use of a load management system, so that the approved power is complied with in any case.
If you have the required charging power available, the next step is to set up a separate metering system, install a busbar and connect as many wallboxes as you like, integrating a load management system.
Visualisation of a busbar fed via the house connection
WHY SHOULD THERE BE A SEPARATE MEASUREMENT?
In order to be able to record and delimit the electricity consumed for charging electric vehicles, a separate measurement is necessary. Depending on the amount of charging power available for electric mobility, it is decided whether a direct measurement or a converter measurement is necessary. The latter is used for outputs of 30 kW or more. If you use your electricity exclusively yourself, e.g. for a company fleet, an additional measurement is not mandatory.
HOW DOES LOAD MANAGEMENT WORK?
A static load management system ensures that the power reserved for charging electric cars is not exceeded. If too many electric cars want to charge at the same time, the load management system intervenes and distributes the available power evenly among the connected vehicles. This avoids power peaks and actively prevents overloading of the connection.
WHY BUSBARS ARE THE MOST SENSIBLE SOLUTION
In order to supply all charging points in the underground car park with electricity and at the same time enable an efficient and cost-effective installation of wallboxes, the use of a busbar is the best possible option.
Advantages of the busbar compared to laying individual power cables per wallbox:
The system has already arrived and been tested in practice. The experts for the installation of charging infrastructure at SachsenNetze GmbH now use the technology as standard in larger underground car park projects. Kai Glaser of SachsenNetze summarises the advantages as follows:
"A large number of charging points can be installed cost-effectively and very flexibly with little installation effort."
Conductor rails in a Dresden underground car park, Photo: Oliver Killig
WHICH WALLBOXES ARE SUITABLE FOR BUSBARS?
It all depends on the purpose for which you are having the charging infrastructure installed. Different wallboxes are suitable depending on the application. However, all of them should be able to be integrated into a load management system. This can either be integrated into the wallbox in the form of a master-slave solution or set up via a separate load management gateway. In the master-slave solution, a wallbox acts as a communication controller. A backend is also integrated here. Intelligent load management is carried out via this controller. It is responsible for ensuring that the maximum available power is not exceeded when electric vehicles are charging at the same time. A LAN connection of the wallboxes is to be installed in parallel to the power supply in the underground car park for communication between the individual wallboxes and their control by the load management.
For Landlord or employer the billing of charging processes at the wallboxes is also an important issue. Here, the wallboxes must have the option of measurement in compliance with calibration law. It must be possible to integrate the charging points into the backend system of a charging station operator via an external communication connection, for example a SIM card or a broadband connection. In the backend, all charging processes of a specific charging card at a wallbox are recorded in compliance with calibration regulations and can be used by the operator as a basis for billing.
Wallbox connected to busbar, photo: Oliver Killig
CONCLUSION: THE INSTALLATION OF BUSBARS IS A SMART INVESTMENT IN THE FUTURE
Busbars save space, resources and money and can be flexibly adapted to new requirements. Even if your fleet expands or more tenants want to charge an electric vehicle, retrofitting wallboxes with intelligent busbar technology is no problem. Landlords and tenants also benefit from the new subsidy for the installation of private charging points. But a busbar is also an excellent basis for setting up public charging points for third parties. Through an external communication connection of the wallboxes to the backend of an operator, the charging current consumed can be billed individually. Providers such as DREWAG already have a complete package ready for their customers - starting with advice on the necessary charging capacity, through the installation of the metering, the busbar and the wallboxes, to the billing and operational management of the charging points.
Would you like to find out more? Do you already know our extensive Whitepaper? Here you will find lots of information if you are planning to add e-cars to your fleet. Do you have any questions about CleverShuttle or a completely different topic idea? Then please send us an e-mail to
