It is important that the connection and operation of storage units is compatible and supports the grid. They can also significantly help to reduce the need for grid expansion, as they offer potential for a flexible power supply, which is important for a stable grid.
Compatible network connection for energy storage
Storage systems are an important component of the energy transition. They offer the possibility to bring more flexibility into the energy system. Especially in combination with renewable energies, they offer the possibility to supply electricity from sustainable sources even when they are not generating electricity.
Nationwide network connection rules for energy storage systems
The VDE Application Rules lay down the technical requirements for the connection and operation of energy storage in Germany. With these Technical Connection Rules (TCRs) VDE|FNN defines the specific requirements for each voltage level for the German power system according to European specifications. In addition, the FNN-Guideline for the connection and operation of energy storage units on the low-voltage network serves as a practical supplement to these regulations.
Aims for the deployment of energy storage
- to locally use, store or feed into the grid all electricity generated from renewable sources
- to relieve the load on the network
- to improve grid operation and reduce the need for network expansion
FNN-Guideline "Connection and operation of energy storage units on the low-voltage network"
VDE|FNN has been publishing orientation guides in the form of technical guidelines for several years. This FNN-Guideline defines how energy storage devices, without highlighting a particular technology, are to be connected to the low-voltage network and how they ought to be operated. Battery storage systems for photovoltaic systems typically found in practice are considered here in detail; showing particularly measurement and connection concepts representing nationwide practices.
In a nutshell, the FNN-Guideline:
- defines different connection variants in a practical manner, depending on the configuration of the generation system on-site
- supplements current Application Rules “Power Generating Plants in the Low Voltage Grid” (VDE-AR-N 4105) and “Technical Connection Rules for Low-Voltage" (VDE-AR-N 4100)
- supports in the application of funding programmes
- details technical requirements for energy flow direction sensors (EFD sensors) for the first time and the standardization of meter numbering according to specifications of the German Association of Energy and Water Industries (BDEW)
The requirements for EFD sensors apply after a transitional period of twelve months. The current data sheet for storage will then be adapted to the new version of this guideline. Until then, the current published version (VDE-AR-N 4105) will apply.
Network operators, manufacturers, the Electrical Trade Association (ZVEH) and the Physical-technical Federal Institute (PTB) are involved in the formulation and continuous revision of the requirements for the connection and operation of energy storage systems on the low-voltage network.
The FNN-Guideline has been translated into English and can be purchased from the VDE- shop.
Please also note our Energy Storage Datasheet:
Target groups and applications
Connection examples and measurement concepts should help all participants to provide proper and transparent billing.
Aspects of system security are addressed at an early stage and allow energy storage to have a positive impact.
|Customers and operators of energy storage facilities||Compliance with minimum technical requirements for network connection and operation and, if applicable, conditions from support programs (e.g. at federal or state level)|
|System installers||Connection examples for integration of storage units into their respective system configuration on-site in a network-compatible manner|
|Network operators||Assurance of network-compatible and network-supportive behavior from energy storage systems connected to the their network|
Basis for network conformity and safe connection of energy storage systems
Uniform standards in Europe
There are currently plans at European level to establish homogenous requirements for energy storage. VDE|FNN supports this development with the FNN-Guideline "Connection and operation of energy storage units on the low-voltage network".
International developments are to be taken into account when setting national rules (especially in the area of EU-Network Codes). National experience in rule-making should be brought into the international process in a timely and appropriate manner.
Currently in progress
Network service requirements for energy storage are still to be further developed in order to meet the increasing challenges of maintaining a secure and reliable network operation.
- System services with storage, such as balancing power
- Connection and measurement concepts in complex measuring points (virtual measuring points)
- Energy management in a customer plant including energy storage facilities
- Aspects of the integration of e-mobility