Control area


A control area is a geographically defined network area within an electricity network, which results from an interconnection of high-voltage or extra-high-voltage networks. It is responsible for the control, security and maintenance of grid stability and is ensured by a transmission system operator (TSO). Four control areas have existed in Germany since 2012. They are the responsibility of the transmission system operators Amprion, 50Hertz, Tennet and TransnetBW.

The control areas are not isolated grids. The boundaries between the various control areas are primarily defined by law. In fact, they are all interconnected by interconnection points, 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 blackouts. Together, the control areas form the German interconnected grid.

The responsibility of the TSOs in the control areas

Transmission system operators (TSOs) play a crucial role in the German energy system, as they are responsible for the secure, reliable and efficient supply of electricity to all players in their control area. In doing so, TSOs take on a variety of responsibilities to ensure that the flow of electricity runs smoothly and that consumers' needs are met. Some core responsibilities in this regard include:  

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

Network operation: TSOs are responsible for the safe and reliable operation of the transmission network. They must ensure that the power supply is continuously guaranteed, bottlenecks are avoided and the frequency and voltage are maintained at an acceptable level.

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

System services: TSOs must ensure that there are no major fluctuations in the grid in their control area. To this end, they provide ancillary services that contribute to the stability of the electricity grid, including the provision of balancing energyreactive power compensation and voltage regulation.

The German interconnected grid

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

The interconnected grid offers the transmission system operators numerous advantages that have a positive impact on the stability and reliability of the energy system. By interconnecting different regions within the grid, local differences between the supply and demand of instantaneous power can be efficiently balanced out. This has the practical benefit that less control power is required in relation to the total installed capacity has to be maintained. This reduction in control power not only contributes to cost savings, but also makes it easier to operate the electricity grid.

At the same time, grid stability is increased. This is because a specific control strategy is pursued within an interconnected grid, which makes it possible to absorb and balance out overcapacities and undercapacities. This is of crucial importance in order to manage fluctuations in electricity supply and demand and thus ensure a continuous supply. The exchange of power within the interconnected grid enables load fluctuations to be regulated quickly and effectively. Compared to the exclusive regulation of power plants, this approach offers a more flexible way of adjusting grid utilization and balancing out short-term fluctuations. This contributes significantly to grid stability and minimizes the likelihood of bottlenecks or outages.

Last but not least, an interconnected grid contributes to increasing the overall reliability of the electricity grid. Linking different grid regions makes it possible to compensate for disruptions 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 occur in one region.