Why net-forming properties are now crucial

As the expansion of renewable energies progresses, the number of conventional power plants, which previously brought natural inertia and therefore stability to the electricity grid due to their rotating masses, is decreasing.

To ensure grid stability even in an electricity system with 100renewable energies to ensure grid stabilitys stabilitynew technicalnew technical solutionssolutions can be established. The grid-forming properties of customer systems play a central role in this. They enable voltage and frequency to be actively pre-set and instantaneous reserve to be provided – essential functions for a stable power grid.

Technical requirements: What does “network-forming” mean?

Grid-forming units behave like inertial voltage sources. They are able to

  • voltage and frequency at their terminals,

  • phase jump power (instantaneous instantaneous reserve),

  • inertia (instantaneous reserve),

  • to be operated at a short-circuit ratio (SCR) of 0,

  • not contribute to the reduction of the effective short-circuit power ratio (ESCR) in the system.

These capabilities are crucial to ensure system stability in an increasingly decentralized and renewable electricity system.

VDE FNN Note: Technical basis for the future

The VDE FNN notice “Technical requirements for grid-forming properties including the provision of instantaneous reserve” defines the necessary technical requirements and evidence for grid-forming customer systems. It provides the technical basis for participating in the planned instantaneous reserve market and thus represents an important milestone in the BMWK’s System Stability Roadmap.

The note applies to:

  • Grid-forming generation units of type 1 or type 2

  • Grid-forming generation and storage units

  • Network-forming storage

  • Grid-forming controllable reference units

It also describes the possibility of converting existing type 2 units with grid-connected technology into grid-forming units.

Market mechanism: the role of the Federal Network Agency

In its decision BK6-23-010, the Federal Network Agency defined the framework conditions for the market-based procurement of instantaneous reserve. Suppliers can offer a self-selected quantity of instantaneous reserve at a unit price set by the transmission system operators. The transmission system operators are obliged to purchase the quantity offered at this price.

This fixed-price procedure is intended to promote a rapid market ramp-up and create incentives for the provision of grid-forming properties. Early offers are remunerated at a higher rate than later offers in order to promote a rapid market ramp-up.

Verification procedure: Certification of network-forming units

Systems that can demonstrate conformity with the requirements fulfill the technical requirements for participation in the instantaneous reserve market. The above-mentioned VDE FNN note describes the procedure for metrological testing and simulative evaluation of grid-forming units and, together with the supplements to FGW TR 3, 4 and 8 that are still to be drawn up, creates the basis for their certification.

The path to a stable, renewable electricity system

The integration of grid-forming properties in customer systems is a decisive step towards ensuring system stability in an electricity system with a high proportion of renewable energies. The technical requirements and market mechanisms have now been defined – it is now up to manufacturers, grid operators and system operators to implement them and play an active role in shaping the electricity system of the future.

Contact us – we will be happy to advise you individually and without obligation.

Our accredited certification body is able to support you at short notice – from checking the technical requirements to the structured planning and implementation of the verification process. Together, we will ensure that your system meets future requirements and actively contributes to grid stability!

Note: The information contained in this blog post is based on the current publications of the VDE FNN and the Federal Network Agency. For detailed technical specifications and legal framework conditions, please consult the original documents.

Tobias Busboom – Managing Director

Please contact me if you have any questions on the following topics:

  • Unit certification

  • Component certification

  • Itemization procedure

As an accredited certification body according to DIN EN ISO/IEC 17065, M.O.E. is recommended by the BDEW list „Assessment and certification of new and existing systems“.

Please feel free to call me at
+49 (0) 4821 6453 – 261