Do­mes­tic grid re­serve

Reserve capacity


1. General

The TSOs conduct annual system analyses for various time periods to determine the future reserve plant capacity necessary for measures to stabilise the grid. If there are not enough power plants in the market for redispach-purposes, the TSO procures the required capacities from available plants that have been marked for closure. These "grid reserve power plants" must have been designated as essential for the electricity system by the TSOs, and they are used solely outside the electricity market to safeguard the security and reliability of the electricity supply system.

Grid reserve plants are contracted and used, without prejudice to legal obligations, on the basis of contracts concluded between TSOs and plant operators in consultation with Ruling Chamber 8 of the Bundesnetzagentur in accordance with the provisions of section 13a ff EnWG and the Grid Reserve Ordinance (NetzResV). One of the components of these grid reserve contracts is the appropriate remuneration TSOs pay to plant operators, which is determined in consultation with the Bundesnetzagentur.

Costs incurred by TSOs for remunerating plant operators are then recognised by a determination from Ruling Chamber 8 on a so-called “voluntary commitment” by the TSOs under section 11(2) sentence 4 and section 32(1) para 4 of the Incentive Regulation Ordinance (ARegV) as regulated and permanently non-controllable costs in accordance with the applicable requirements, which can be recovered through the network charges.

The costs for the grid reserve vary, depending on whether


- domestic power plants with a final or provisional closure notification were used (referred to as domestic grid reserve)
- or if foreign power plants active in the market were used after participating in an expression of interest procedure and qualifying for the grid reserve to provide additional capacity to meet demand for generation (referred to as foreign grid reserve).


2. Domestic grid reserve


a.) Plants with final closure notification

The provisions for the remuneration of plant operators whose facilities may not be permanently closed because they are essential for the system under section 13b(5) sentence 1 EnWG are described in section 13c (3) and (4) EnWG and sections 10 and 6 NetzResV. According to these provisions, an operator of such a plant can claim appropriate remuneration for its grid reserve obligations applicable under section 13b(5) sentence 1 EnWG from the TSO responsible for the system.
The appropriate remuneration includes the following standard, specified costs:

  • maintenance costs
  • non-recurring costs for making the facility operationally ready
  • costs for keeping the facility available for use
  • generation costs
  • certain opportunity costs
  • pro rata depreciation

Additional costs, particularly costs that would have been incurred in the case of a final closure, are not reimbursable.

The maintenance costs and the necessary costs for making and keeping the facility ready for use (operational readiness costs) are to be reimbursed if and to the extent that they are incurred by the TSO after the power plant has been designated as essential for the system and these costs are committed to operation in the grid reserve.

Thus reimbursement costs for maintenance measures not related to maintaining operability of the plant for operation in the grid reserve are not allowed.

Those power plants of the grid reserve that were originally marked for final closure and leave the grid reserve may no longer be operated on the electricity markets (referred to as “prohibition to return”). When such a power plant is actually closed after leaving the grid reserve, the plant operators must reimburse the TSO the residual value of investment benefits in accordance with legal regulations.


b.) Plants with provisional closure notification

The provisions for the remuneration of plant operators whose facilities may not be provisionally closed because they are essential for the system under section 13b(4) sentence 1 EnWG are described in section 13c(1) and (2) EnWG and sections 9 and 6 NetzResV. According to these, an operator of such a plant can claim appropriate remuneration from the TSO responsible for the system if the TSO has requested the operator, in accordance with section 13b(4) EnWG, to keep or restore operational readiness of the plant for feed-in adjustments.

The appropriate remuneration includes the following standard, specified costs:

  • one-off costs for making the facility operationally ready
  • costs for keeping the facility available for use
  • generation costs
  • pro rata depreciation

The costs for making and keeping the facility ready for use (operational readiness costs) are to be reimbursed if and to the extent that they are incurred by the TSO after the power plant has been designated as essential for the system and these costs are committed to operation in the grid reserve. The facility operator can claim cost reimbursement from the point in time when testing for system essentiality has been completed and the plant has been designated as essential for the system.

Only those costs are to be reimbursed that the facility operator additionally incurs as a result of taking the security measures requested by the TSO. Costs that also would have been incurred in the event of a provisional closure or by later returning to the electricity markets are non-refundable (see also section 9(2) sentence 2 NetzResV).

If the facility operator uses the TSO for paying operational readiness costs, the facility operator may only operate the power plant in question from that point on outside the electricity markets for as long as the plant is designated as essential for the system in accordance with system security measures ordered by the TSOs (referred to as market ban).

Unlike the plants with final closure notification, plants with only provisional closure notification can be operated again independently on the electricity markets after leaving the grid reserve. The facility operator must reimburse the TSO the residual value of an investment benefit gained by the facility operator due to the grid reserve, for example for renewing part of a facility.

A list of domestic grid reserve proceedings can be found here (in German): Verfahrensliste inländische Netzreserve (pdf / 88 KB)

Ruling Chamber 8 information about the domestic grid reserve (in German):

Hinweis Herstellungskosten Netzreserve (pdf / 152 KB)
Hinweis Opportunitätskosten Netzreserve (pdf / 212 KB)
Anlage 1_Ermittlung der Opportunitätskosten nach § 13c Abs. 3 S. 1 Nr. 4 EnWG (pdf / 29 KB)

Date of modification: 2021.09.03