(As of June 2026) ZEREZ is the central register for unit and component certificates of generating units of all voltage levels in Germany. It provides a central platform for collecting, storing and making available evidence of the electrical properties of generation units and components. ZEREZ is operated by FGW e.V., the Fördergesellschaft Windenergie und andere dezentrale Energien, which has been entrusted with this task since July 2024.
Purpose & advantages of ZEREZ
Since February 1, 2025, the use of ZEREZ legally binding. The aim is to strengthen the safety and reliability of the energy supply by making grid connection procedures more efficient and transparent. This applies in particular to all units and components in accordance with the VDE technical connection rules (VDE-AR-N 4105, 4110 and 4120) for the entire Plant certificate. The most important advantages at a glance:
- Manufacturers can securely and securely Publish centrally.
- Certification bodies can Uncomplicated changes and the Duty of supervision perceive.
- Network operator receive fast and easy access to all necessary Certificate data.
The register entries facilitate the grid connection processas all relevant information such as performance values and parameters are provided via the unique ZEREZ ID. This saves planners and operators of decentralized energy systems time and effort.
Legal basis & use
The legal basis for ZEREZ is set out in the § 49d of the Energy Industry Act (Energy Industry Act) and the Electrotechnical Properties Verification Ordinance (NELEV) anchored. Manufacturers and certification bodies have already been able to voluntarily enter their certificates for several months. Since February 2025, the register entry is mandatory. The connection of systems without a valid certificate to the public power grid will then no longer be possible.
Functionality of the certificate register
ZEREZ lists all certificates that prove the electrical properties of generating units and components. These certificates are only issued by accredited certification bodies. The most important functions include
- Clear identification by the ZEREZ-ID: Each certificate is given a registration number.
- Access for authorized bodies: Grid operators can view the certificates required for the grid connection check.
- Data security and efficiencyThe digital platform replaces the previous postal transmission of documents and enables a dual control principle between manufacturers and certification bodies.
Mandatory since February 2025
Since February 2025, systems and units subject to certification may only be connected to the power grid with a certificate registered in ZEREZ. This particularly affects:
- Photovoltaic systems (inverters and additional components)
- Battery storage systems or Battery storage
- Combined heat and power plants and other power generation units
Network operators will check the completeness of the certificates using the ZEREZ ID before commissioning takes place.
ZEREZ expanded to include certificates for grid-forming capabilities
With the further development of Current reserve-market, the functional scope of ZEREZ was also expanded. Since June 2026 manufacturers and certification bodies can also store and manage plant and component certificates with grid-forming properties in the register.
The extension concerns certificates that meet the requirements of the VDE FNN guidance document „Technical requirements for grid-forming properties including the provision of synthetic inertia“. With this, ZEREZ is responding to the increasing demands on system stability and the growing importance of grid-forming technologies in the German power system.
The new function is available for systems in the medium, high, and extra-high voltage levels in accordance with the technical connection rules VDE-AR-N 4110, 4120, and 4130. In particular, operators of battery storage systems and other power-electronic generation plants benefit from standardized and transparent documentation of their grid-forming properties.
As with all other certificates, the stored data remains accessible via the digital ZEREZ interface. Network operators, certification bodies, and other market participants can use the information in an automated manner, which further simplifies both certification and grid connection processes.
ZEREZ as a digital solution
With ZEREZ, the energy industry has been provided with a centralized and digital solution that both simplifies grid connection procedures and improves the security and reliability of the power grid. CUBE CONCEPTS welcomes the long-overdue online certificate register. Voluntary use during the transition period ended in February 2025, giving all stakeholders time to prepare for the new processes.