Control area


A control zone is a geographically defined network area within a power grid, which results from a network of high-voltage or extra-high-voltage networks. It is responsible for managing, securing and maintaining grid stability and is ensured by a transmission system operator (TSO). Since 2012, there have been four control zones in Germany. They are managed by transmission system operators Amprion, 50Hertz, Tennet and TransnetBW.

The control zones are not isolated island networks. The boundaries between the various control areas are primarily defined by law. In fact, they are all connected by interconnections through which electricity generated in Germany and its neighboring states constantly flows. Transmission system operators coordinate with each other to ensure that electricity can flow freely between regions. This coordination is important to keep the power grid stable and prevent power outages. Together, the control zones form the German network.

The responsibility of the TSOs in the control areas

Transmission system operators (TSOs) play a decisive role in the German energy system, as they are responsible for the safe, reliable and efficient supply of electricity to all players in their control area. Transmission system operators assume a variety of responsibilities to ensure that electricity flows smoothly and that consumer needs are met. Some core tasks include:

Network planning and development: EUNBs must plan, develop and operate the transmission system to ensure that there is sufficient transmission capacity to meet the needs of consumers and electricity producers in their control area. This includes identifying bottlenecks and implementing network expansion projects when necessary.

Network operation: ÜNBs are responsible for the safe and reliable operation of the transmission grid. They must ensure that power is continuously supplied, bottlenecks are avoided, and frequency and voltage are kept at acceptable levels.

Market integration: EUNBs play an important role in the integration of renewable energy sources and in the efficient use of the transmission grid by the electricity market. They must ensure that electricity producers and consumers have fair and non-discriminatory access to the grid.

System services: In their control area, UENBs must ensure that there are no major fluctuations in the network. To this end, they provide system services that contribute to the stability of the power grid, including the provision of Control energy, reactive power compensation and voltage regulation.

The German network

All four control zones are connected to each other through interconnections — together they form the interconnected network. This ensures that electricity can flow freely between all regions. The electricity flows in the interconnected grid are coordinated by transmission system operator Amprion. To this end, all planned energy transfers for the following day are coordinated among the TSOs.

The interconnected grid offers transmission system operators a variety of advantages that have a positive effect on the stability and reliability of the energy system. By connecting different regions within the network, local differences between the supply and demand of current power can be efficiently balanced out. This has the practical advantage that less control capacity in relation to the total installed power must be held back. This reduction in control power not only contributes to cost savings, but also makes it easier to operate the power grid.

At the same time, grid stability is being increased. This is because within an interconnected network, a specific control strategy is followed, which makes it possible to absorb and compensate for excess capacities and undercapacities. This is crucial to manage fluctuations in electricity supply and demand and thus ensure a continuous supply. The exchange of power within the interconnected network enables rapid and effective regulation of load fluctuations. Compared to exclusively controlling power plants, this approach offers a more flexible way of adjusting grid utilization and compensating for short-term fluctuations. This contributes significantly to grid stability and minimizes the likelihood of bottlenecks or outages.

Last but not least, an interconnected network contributes to increasing the overall reliability of the power grid. Linking different grid regions makes it possible to compensate for faults or outages in one region through the availability of electricity from other regions. This ensures that the power supply is continuously guaranteed, even if problems should arise in a region.