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The start of electrification in Germany

The electricity system in its current form is a construct that emerged from historical developments of the past century. Early 20th-century technology allowed the supply of electricity only to users in the immediate vicinity of power generators. The so-called supply islands mainly developed in urban areas and conurbations. By the First World War, such generation pockets were managed by 4040 companies with a total installed capacity of 2096 MW, i.e. an average 500 kW per power plant.

The isolated positions of the individual power plants, however, meant that an outage in one plant led to immediate interruption of power supply to the connected load. This situation changed with increasing industrialisation that triggered rising demand for electricity and service security. Step by step, all existing German electricity supply companies interconnected their extra-high voltage subsystems creating an interconnected grid to provide electricity service even when no power plant is available in the surroundings. Demand fluctuations or extreme weather situations are mastered with the help of the system and the power plant capacity kept in reserve.

The origin of the German and European interconnected grid

In 1930, the first extra interconnector at extra high voltage level (220 kilovolts) was constructed for the transport of electricity between regional grids. As a result, coal-fired power plants in the Rhine district could for instance be connected to the hydro-electric power plants in the Alps. In the following years, the interconnected grid was further expanded: by 1945, a 220 kilovolt interconnected grid was created to connect the most important power plants of the Ruhr area, central and southern Germany. The electricity generated there could now be distributed to the connected regional grids.

From the 1950s onwards, cross-border cooperation in the energy sector gradually increased. This led to the merger in 1951 of the grids of eleven states with the European UCPTE interconnected grid. Meanwhile, Germany began expanding its 380 kilovolt interconnected grid.

Development of the interconnected grid in former East Germany (GDR)

At the end of 1975, the GDR had an extra-high voltage system of over 7,600 circuit kilometres in place, mainly at a level of 220 kV. By 1990, the GDR grid had been expanded to a circuit length of 4,312 km at 380 kV and 6,416 km at 220 kV. There were 16 substations and switching stations with a high-side voltage of 380 kV and 39 with a high-side voltage of 220 kV.

Development after German reunification

Based on the so-called electricity contract of 22 August 1990 involving the East German government, the Treuhandanstalt privatisation agency, the large West German interconnected grid operators and five smaller enterprises, the new interconnected system operator Vereinigte Energiewerke AG (VEAG) was incorporated on 12 December 1990. The major East German power plants and the extra-high voltage grid were combined under the umbrella of VEAG in February 1991. Management services to VEAG were provided by West German electric utility companies Preussen-Elektra, RWE and Bayernwerk.

In 1994, VEAG was, at a price of six billion deutschmarks, sold to a consortium consisting of the seven West German utility companies. Preussen-Elektra, Rheinisch-Westfälische Elektrizitätswerke (RWE) and Bayernwerk held a share of 75%, and 25% went to EBH, a holding company owned by utility companies BEWAG, VEW, Badenwerk, EVS and HEW.

In 2001, Hamburgische Electricitäts-Werke (HEW), a subsidiary of the Swedish state-owned utility company Vattenfall since 2000, acquired the majority of shares in VEAG. HEW, lignite-mining company LAUBAG and BEWAG were then merged with VEAG into a new company, Vattenfall Europe, in September 2002. As early as June 2002, the transmission system was the first company spun off VEAG to become a Vattenfall Europe subsidiary. The initial leases of transmission system assets in Hamburg and Berlin were followed by an asset transfer to VE Transmission GmbH in 2006.

In 2008, Vattenfall Europe AG announced its intention to divest its transmission system and put VE Transmission up for sale. The company was renamed 50Hertz Transmission GmbH, 50Hertz in brief, on 05 January 2010.

Since 19 Mai 2010, 50Hertz has had new owners. Belgium transmission system operator Elia now holds 60% of the company's shares with 40% held by Australian infrastructure fund IFM Investors.


Historical development in north and east Germany



It was in 1887 that the city government erected a central station for public power supply which passed into ownership of the newly established stock corporation ”Hamburgische Electricitäts-Werke“ (HEW) in 1894. This utility company gradually expanded its electricity service into Hamburg’s suburbs. The year 1903 saw the introduction of three-phase electricity generation at a voltage of 5 kV, coupled to the direct-current system via converters. This permitted balancing between the load and the economically viable generation capability - an early example of interconnected operation, in this case within a company. In 1914, the city state of Hamburg acquired 50% of the equity of HEW. The service territory was expanded to cover the entire territory of Hamburg. The HEW network was operated as an island system up until 1944.

In 1988, HEW acquired a majority interest in the Hamburg gas supplier Hamburger Gaswerke GmbH.


The Berlin city government established the municipal electric utility company Berliner Städtische Elektrizitätswerke Berlin (later called BEWAG) in 1915. Between 1919 and 1929 the Berlin-Charlottenburg and Klingenberg power plants were rebuilt and enlarged, and a steam accumulator was built in Charlottenburg. Construction of the large-scale power plant West, later called Reuter power plant, commenced in 1929. The two separately managed 6 kV electricity distribution networks were superimposed by a 30 kV system connecting all power plants. Berliner Kraft- und Licht-Aktiengesellschaft (BKL), a company incorporated in the 1930s, was merged with BEWAG into Berliner Kraft- und Licht (BEWAG)-Aktiengesellschaft in 1934.

Bewag operated the electricity system of what had later become West Berlin as an island system until 1993, which required the construction of numerous urban power plants. Today, Bewag, after having been renamed Vattenfall Europe Berlin on 01 January 2006, is part of the Swedish Vattenfall Group.


Managed by AEG and Siemens, the rollout of electricity supply systems to Mark Brandenburg, the region surrounding Berlin, started in 1909. The local electricity supply system Märkisches Elektrizitätswerk (MEW) was expanded by the provincial administration into a general regional supply system in 1915. A stock swap performed in 1930 made MEW the supplier responsible for delivering electricity to the east German regions of Brandenburg, Pomerania, Mecklenburg and Grenzmark.


In 1912, 50 towns, villages and associations of municipalities established the Association of Municipally Owned Power Plants (Elektroverband). The state of Saxony declared electricity supply the responsibility of the state government after it turned out that Elektroverband proved unable to implement its plans for the construction of power plants and high-voltage lines. The Directorate of State Electric Utilities (ELDIR) was established in 1915 and renamed AG Sächsische Werke (ASW) in 1923. The Saxon government remained the sole shareholder. The 110 kV lines of ASW had already reached a circuit length of 695 km by 1935.


The electricity service landscape in the German state of Thuringia used to be highly fragmented, with a large number of regional electric utilities. The network of Thüringische Landeselektrizitätsversorgungs-AG (Thüringenwerk) operated the large-scale Erfurt power plant, the power plant of the Bleiloch storage dam on the river Saale, and a hydropower plant on the Werra river. Electricity delivery contracts were signed with ASW and Preussenelektra.


Electric utility company Elektrizitätswerk Sachsen-Anhalt AG was established in 1917, with Deutsche Continental-Gesellschaft in Dessau and the Saxon provincial association Provinzialverband Sachsen as two of the major players involved. In January 1922, the Zschornewitz power plant began delivering electricity to Magdeburg via the new 110 kV line running from Zschornewitz via Dessau to Magdeburg. The following years saw the construction of a high-voltage line from Großkaina via Mansfeld to Nachterstedt. A cross-link between Nachterstedt and Förderstedt was added in1927, closing the 110 kV loop.


The German transmission system

The rising demand for energy and the need to bridge increasing distances have over the decades required ever higher transmission voltages. Employing a range of voltages allows transport to be handled with a minimum of loss and maximum economic efficiency. High voltages are needed to bridge long distances and minimise transport losses. At the highest level, the supra-regional transmission grid, electricity is transmitted at extra-high voltages of 380 kV or 220 kV, across long distances from large-scale power plants connected to the extra-high-voltage system to centres of electricity use – including to European neighbours. The second level includes the distribution system operators of the regional electricity companies. They distribute electricity at a voltage of 110 kV in relatively large areas, where it is fed into the local networks: the low-voltage system. The various voltage levels are connected to one another via substations. Here, the voltage is transformed to higher or lower voltages.