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What is control energy? (Prequalification)

Balancing Market in Germany

The German transmission system operators (TSOs) have to maintain the balance between electricity generation and consumption within their control areas at all times. For the performance of this task, the TSOs need different types of control reserve

  • Frequency Containment Reserve (FCR)
  • Frequency Restoration Reserve with automatic activation (aFRR)
  • Frequency Restoration Reserve with manual activation (mFRR)

The German TSOs procure all control reserves (balancing capacity and balancing energy) commonly across their control areas and partly in cooperation with neighbouring countries. The tendering is open, transparent and free from discrimination according to guidelines of the Federal Cartel Office (Bundeskartellamt - BKartA), the national regulatory authority (Bundesnetzagentur) and EU Guidelines.

Precondition for providing balancing services is the pre-qualification procedure of each balancing service provider (BSP) at the connecting TSO. The possibility of pooling/aggregation enables small technical units as well as loads to deliver balancing services. The terms and conditions for BSPs contain the market rules from qualification to settlement for all market participants.

The scope of a systematic further development of joint procurement, the German TSOs cooperate at operational level through the coordinated use of control reserve in the grid control cooperation (GCC) and activate control reserve across control areas at minimal costs.

This way of close cooperation will be extended across borders the next years with the objective to optimise the activation of all reserves across all EU TSOs.

General information on control reserve - technical aspects

A permanent balance between electricity generation and demand is an important precondition for the stable and reliable operation of the grid. Ensuring that their customers are supplied with power in a reliable fashion is the foremost of TSOs' responsibilities. For the purpose of maintaining the above-mentioned balance between supply and demand, TSOs procure control reserve (also known as balancing power).

A need for control reserve arises as soon as the current feed-in differs from current consumption. Deviations are caused by fluctuations on the consumer side in the supply and consumption behaviour or on the generation side due to disturbances (e.g. power outages). A lack of generation capacity (or excess of power consumption) is expressed as a frequency drop, an excess of generating capacity (or lack of power consumption) as a frequency increase in the total electric energy supply system in Europe.

The objective of control reserve activation is, on the one hand, to maintain the system frequency within a narrow range around its target frequency of 50 Hz and, on the other hand, to eliminate regional deviations in the balance from their reference value. For this purpose, different types of control reserve have to be deployed in a coordinated fashion for a dynamic and chronological interaction.

Based on the valid rules of ENTSO-E (European Network of Transmission System Operators for Electricity), the German TSOs procure the following types of control reserve:

Frequency Containment Reserve:

  • Provided according to the solidarity principle by all TSOs synchronously connected within the ENTSO-E area
  • Automatic and complete activation of FCR within 30 seconds
  • Period per incident to be covered: 0 < t < 15 min

automatic Frequency Restoration Reserve:

  • energy balance of the control area and frequency control
  • immediate automatic activation by the concerned TSO
  • complete activation within five minutes (at most)

manual Frequency Restoration Reserve:

  • The activation is based on MOLS by a Merit-Order-List (electronical activation) since 2012
  • Complete activation within 12.5 minutes
  • Period per incident to be covered t > 15 min to 4 quarter hours or up to several hours in case of several incidents

For further information see the  ENTSO-E-Operation Handbook