Few people know what a substation actually is. Yet there are far more than three thousand of them in Germany. They are the central hubs of our electricity supply. Power lines are connected in a substation, the electricity is transformed to different voltage levels and then passed on to consumers at suitable voltage levels. You can find out more about substations in this blog article.

A substation is a technical facility within an electricity grid that is used to convert electrical energy between different voltage levels. This conversion is necessary in order to transport electricity efficiently over long distances at extra-high voltage levels and then distribute it to consumers at suitable lower voltages. The substation therefore collects the energy from the power plants, converts it to lower voltage levels and distributes it further.

Source: TenneT (Very comprehensive and detailed brochure about substations; only available in German language)

Substations are important for the distribution and transmission of electrical energy over long distances. They are used to reduce the voltage of the different voltage levels or vice versa, depending on requirements. This is done by transformers.

Here are some reasons why substations play a central role in the power grid:

1. Voltage conversion: Substations convert the voltage from extra-high voltage to a lower voltage level suitable for distribution to homes and businesses. This makes it possible to transport electricity efficiently over long distances, as higher voltages reduce the loss of energy over lines.
2. Grid stabilization: Substations play an important role in stabilizing the electricity grid. They control the voltage and current flow to ensure a reliable supply and prevent overloads.
3. Grid integration: They enable the integration of renewable energy sources by feeding the energy generated by wind farms, solar power plants or other renewable sources into the electricity grid.
4. Grid protection: Substations serve as protective mechanisms that can intervene in the event of faults or malfunctions in the grid to minimize outages and ensure security.
5. Load balancing & security of supply: By distributing and controlling the power supply in a targeted manner, substations help to ensure security of supply and manage peak loads.

Overall, substations are therefore crucial for the efficiency, safety and reliability of the electricity grid by providing the right voltage level for the distribution and use of electrical energy.

According to current estimates and information, there are well over 3,000 substations in Germany that are responsible for the distribution and transmission of electricity. In a report from 2022, the Federal Network Agency writes of a total of “3,625 registered substations”. Researching the exact number is not entirely trivial.

There are several reasons for this:

The reports and maps of the Forum Grid Technology/Grid Operation (VDE FNN for short) and the Federal Network Agency are recommended in order to obtain an accurate and up-to-date figure. The Network Development Plan Electricity provides detailed information on the current status and planned expansions of the electricity grid, including the number and locations of substations.

Interactive map „German extra-high voltage grid 2024“:

The VDE FNN provides an overview of the extra-high-voltage grid in Germany with an interactive map (only available in German language) of the electricity grid, including details of power lines, substations and power plants. This map is regularly updated by VDE FNN and the four transmission system operators (50Hertz Transmission, Amprion, TenneT TSO and TransnetBW).

Sources:
Forum Grid Technology/Grid Operation (VDE FNN) (Link leads to the interactive map “German extra-high voltage grid 2024”, only available in German language)
Netzentwicklungsplan.de/en (Link leads to the “Network Development Plan Electricity” for Germany)
Federal Network Agency (“Report on the status and expansion of the distribution grids 2022”, p. 42; only available in German language)

According to Stromnetz Hamburg, the electrical energy arrives in the Hamburg supply area at 380 kV. The electrical energy is converted to 110 kV via three main substations (substations for high voltage) and the electricity is then transformed from high voltage (110 kV) to medium voltage (10 kV) in 55 substations throughout Hamburg.

Main substations in Hamburg in 2024: 3
Substations in Hamburg in 2024: 55

Souce: Stromnetz Hamburg (Source is only available in German language)

Substations are crucial for grid operators as they form the interface between extra-high voltage transmission and low voltage distribution, enabling grid operators to efficiently transmit, transform and distribute electrical energy to ensure a reliable power supply.

According to Statista, a total of 866 electricity grid operators were counted in Germany in 2023. Compared to 2013, the number has decreased by 17. Electricity grid operators can be divided into transmission grid operators and distribution grid operators. The transmission grid is connected to the distribution grid operators‘ grids via substations.

Transmission system operators in Germany in 2023: 4
Distribution system operators (DSOs for short) in Germany in 2023: 866

In Germany, there are four main grid operators (transmission system operators) in the energy supply sector, which are responsible for the infrastructure of the supra-regional electricity grids:

1. 50Hertz Transmission GmbH
2. Amprion GmbH (transmission system operator with the highest turnover in 2021)
3. TenneT TSO GmbH
4. TransnetBW GmbH

These grid operators are responsible for the extra-high and high-voltage grid, which is used to transport electricity over long distances. They play a crucial role in ensuring the stability and efficiency of the German electricity grid. The current 866 distribution grid operators are responsible for low- and medium-voltage electricity grids. They supply private households with electricity, for example.

Source:
Statista (Statistics “Number of electricity grid operators in Germany until 2023”, published in July 2024; only available in German language)

Substations play a crucial role in the electricity grid and are indispensable for Luana AG in order to ensure a stable and efficient energy supply. Through their functions for voltage conversion, grid stabilization and integration of renewable energies, they contribute significantly to the sustainability and reliability of our energy supply. As an important interface between transmission and distribution, substations enable us to meet the growing demands on the modern electricity grid and offer future-proof solutions.◼