Market-based procurement of inertia of local grid stability

The first consultation of the procurement concept was initiated by the BNetzA on September 29, 2023, the second consultation started one year later on September 12, 2024. The final determination of the procurement concept by the BNetzA took place on April 24, 2025.

What is Inertia of local grid stability?

Inertia of local grid stability is an inherent reaction to an active power imbalance in order to prevent a violation, even if only local, of frequency stability limits, which can be critical for grid stability. Inherent reaction means in particular the Inertia from synchronous machines (rotating mass) or grid-forming converters (synthetic rotating mass), which has the aim of limiting frequency gradients. The Inertia reacts instantaneously to short-term changes in the voltage angle, counteracts the active power imbalance and limits the frequency gradient at the origin.

Market design (according to BNetzA definition)

The procurement of Inertia takes place via a fixed price system that remunerates the provision of iInertia. The level of remuneration depends on the availability of the unit in the respective billing period, the procurement region and the product offered. The fixed price is determined on the basis of a methodology drawn up by an independent expert.

The products are differentiated according to direction (positive / negative) and availability (basic / premium), resulting in four different products.

The inertia of local grid stability procurement concept regulates the framework for

  • Remuneration requirements
  • Product definitions
  • Deadlines
  • Availability
  • Framework conditions for pricing
  • Remuneration
  • Publication obligations of the procuring TSO


Market communication

The TSOs plan to hold regular online stakeholder workshops until the market launch in order to provide information on the relevant aspects of market-based procurement of instantaneous reserve.

The following table lists all currently planned stakeholder workshops. Workshops that have already been held are also listed, including the presentations shown.

Date of the workshoptopicMaterialsRegistration
November 28, 2024Market design (2nd consultation)Slide set Stakeholder workshop Market design (2nd consultation) (in German)-
September 22, 2025, 1:00 p.m. – 3:00 p.m.Schedule, mark design, and availability determinationUpload takes place after the appointmenthttps://events.teams.microsoft.com/event/693fccbb-00e5-4527-8371-11d02ca5c986@c37af449-e5b1-455b-a3c2-8ce2c2020e4e
October 22, 2025, 10:30 a.m. – 12:00 p.m.Submission of bids and sample contractUpload takes place after the appointmentfollows
November 24, 2025, 1:00 p.m. – 3:00 p.m.Billing and data exchangeUpload takes place after the appointmentfollows
January 13, 2026, 1:00 p.m. – 2:00 p.m.Q&A-follows
February 24, 2026, 1:00 p.m. – 2:00 p.m.Q&A-follows

For data protection reasons, it is unfortunately not possible to record the dates. However, relevant questions will be included in the Q&A afterwards.

Q&A on the inertia of local grid stability procurement procedure

Here, the 4ÜNB publish answers to provider questions of general interest in anonymized form at regular intervals. Provider questions can be addressed to the network operators using the contact details below.In addition to the new questions and answers, the previous ones are also included in the new publications. However, past answers may be supplemented in new publications, and this will be indicated separately.

Contact with the TSOs

If you have any questions about the market-based procurement of inertia of local grid stability, please contact the responsible TSO: