The final determination of the procurement concept by the BNetzA took place on April 22, 2025.
What is instantaneous reserve?
Instantaneous reserve is an inherent response to an active power imbalance in order to prevent a violation of frequency maintenance limits, even if only local, which could be critical for grid stability. An inherent response refers in particular to instantaneous reserve from synchronous machines (flywheel mass) or grid-forming converters (synthetic flywheel mass), which aims to limit frequency gradients. The instantaneous reserve reacts immediately to short-term changes in the voltage angle, counteracts the active power imbalance, and limits the frequency gradient at its source.
Regulatory framework and market design
Instantaneous reserve is procured via a fixed-price system that remunerates the provision of instantaneous reserve. The amount 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 using a methodology developed by an independent expert.
The products are differentiated according to direction (positive/negative) and availability (basic/premium), resulting in four different products.
The “instantaneous reserve” procurement concept regulates the framework for
- Remuneration requirements
- Product definitions
- Deadlines
- Availability
- Framework conditions for pricing
- Remuneration
- Publication obligations of the procuring TSO