Imbalance Netting

The International Grid Control Cooperation (IGCC) is the implementation project chosen by ENTSO-E in February 2016 to become the future European Platform for the imbalance netting process (IN-Platform) as defined by the guideline on electricity balancing (EBGL Art. 22). IGCC was launched in October 2010 as a regional project and has grown to cover 20 countries (23 TSOs) across continental Europe, including all those that need to implement the IN-Platform according to the EBGL.

In particular, IGCC counts with 20 member TSOs ā€“ AT (APG), BE (Elia), CH (Swissgrid), CZ (CEPS), DE (50Hz, Amprion, TenneT DE, TransnetBW), DK (Energinet), EL (ADMIE), FR (RTE), HR (HOPS), IT (Terna), NL (TenneT NL), PL (PSE), PT (REN), RO (Transelectrica), RS (EMS), SI (ELES) and ES (REE) ā€“ and 3 observer TSOs ā€“ BG (ESO), HU (MAVIR) and SK (SEPS).

IGCC member TSOs are either operational members, also known as participating TSOs (i.e. those physically connected to the IGCC through communication lines that perform imbalance netting via the platform), or non-operational members (i.e. those actively taking part of the IGCC decision-making process but not yet performing the imbalance netting process). There are 11 operational members and 9 non-operational members. The operational members are the TSOs of Germany, Denmark, the Netherlands, Switzerland, Czech Republic, Belgium, Austria and France.

Basic principle of imbalance netting

As part of the responsibility of TSOs towards electricity transmission systems, the IGCC operational members are obliged to maintain the balance between electricity generation and consumption at all times in their respective LFC areas.

Imbalance netting is the process agreed between TSOs of two or more LFC areas that allows avoiding the simultaneous activation of frequency restoration reserves (FRR) in opposite directions by taking into account the respective frequency restoration control errors as well as the activated FRR, and by correcting the input of the involved frequency restoration processes accordingly. IGCC performs imbalance netting of automatic frequency restoration reserves (aFRR).

Figure 2. Imbalance netting in IGCC

The implementation of the process is based on the communication of the power-frequency control of a single TSO, which enables online balancing of the different power imbalances. The aFRR demand of participating LFC areas is reported to the aFRR optimisation system, which returns a correction signal to the secondary controllers or aFRR optimisation system of each IGCC operational member after each optimisation step. In this sense, the counter activation of the aFRR is avoided and therefore the use of aFRR is optimised.

Historical evolution

The implementation of the first development phase of the Grid Control Cooperation (GCC) between German TSOs made it possible to implement the imbalance netting process, which was originally established in 2010 to avoid the counter activation of aFRR in Germany. Shortly after, the German cooperation was expanded to other countries, and the International Grid Control Cooperation (IGCC) was born. Imbalance netting across LFC areas enables all participating TSOs to decrease the use of balancing energy while increasing system security. In 2018, nine TSOs became IGCC members by signing a so-called light accession agreement, allowing them to take part in the decision-making process of IGCC while not yet becoming operational (i.e. not performing the imbalance netting process).

IGCC interchange volumes

The volumes of the exchanged energy of each IGCC operational member are published in real time on a German online tool

IGCC settlement principles

The volumes of the exchanged energy of each IGCC operational member are settled according to the rules described in the linked document:

IGCC Operational support

In case of problems with operational security, IGCC operational members may support each other by reducing their participation upon request. Each IGCC operational member notifies other IGCC operational members about planned or unplanned temporary reductions or suspensions of its participation in IGCC.

In general, an affected TSO (including non-IGCC members) can request a temporary reduction or suspension of participation of any IGCC operational member. Each affected TSO has to use the IGCC standardised procedure in order to request such a reduction or suspension: this is usually set as well in the system operation agreements between concerned IGCC member(s) and the affected TSO. Therefore, at least the following information shall be required by the IGCC member from the affected TSO to keep consistency and simplicity in case of finding the information:

  • brief description of reason(s) for the reduction or suspension;
  • starting time and duration of the reduction or suspension; and
  • defined Limits.
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