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The four transmission system operators
The four German transmission system operators (TSOs) plan and maintain Germany’s ultra-high voltage grid and regulate grid operations. They contribute their expertise and experience towards ensuring the secure expansion of the grid and are thus responsible for the security and stability of the German power supply system. This means that they must guarantee the uninterrupted exchange of electricity across all regions using their power lines and also ensure that generation and consumption levels are balanced at all times. Over the coming decades, the main task of the four TSOs will therefore be to establish an energy supply infrastructure for Germany that is fit for the future and equipped with up to date, efficient and environmentally friendly technology.
11,000 km long, running through seven German states – from Lower Saxony to the Saarland and all the way to the Austrian and Swiss borders – Amprion operates Germany’s longest ultra-high voltage grid from its company headquarters in Dortmund. In a grid covering 73,100 km², Amprion supplies 29 million people with energy around the clock – almost 1,250 members of staff are employed at numerous company locations to guarantee a stable, secure and economically viable electricity supply.
Amprion plans to invest 5,6 billion euro in its transmission grid by 2026. The main shareholders are German financial investors from the insurance and pension fund industry. RWE AG holds a minority share.
Amprion has a very important position in the electricity market thanks to its central geographic location. The TSO also plays a key role beyond the borders of its own region – from its company headquarters in Dortmund and Brauweiler near Cologne, the company carries out vital tasks in coordinating Germany’s four control areas as well as in the field of international energy transport. Amprion maintains interconnecting lines to nine foreign TSOs and can thus fulfil the demands of European electricity traders with the highest levels of safety during transport. These capacities will continue to grow over the coming years.
50 Hertz Transmission
Over 40% of Germany’s installed wind energy output derives from the 50Hertz control area. This means that the company is not only responsible for providing electricity to 18 million people, but also for one of the largest energy export regions in Europe. It is a world leader in the integration of energy from renewable sources.
At 50Hertz, eight locations with around 950 members of staff are kept busy ensuring a constant electricity supply to their region. 50Hertz’s grid area comprises around 109,360 km², covering Berlin, Brandenburg, Hamburg, Mecklenburg-West Pomerania, Saxony, Saxony-Anhalt and Thuringia. The 9,980 kilometre-long grid is managed and monitored from the Transmission Control Centre in Neuenhagen, near Berlin. Company headquarters are located in Berlin. 50Hertz is also responsible for connecting Germany’s offshore wind farms in the Baltic Sea to the national grid. EnBW Baltic 1, the first commercial offshore wind farm in the Baltic Sea, has officially been in operation since May 2011.
Belgian transmission system operator Elia and the Australian infrastructure fund manager IFM Investors are shareholders in 50Hertz, which is part of the international Elia Group.
From the Danish border to the Alps; covering 140,000 km² – about 40% of Germany’s total area – more than 20 million people rely on the electricity supply from TenneT TSO GmbH. The TenneT company consolidates the knowledge and innovation of two countries – in October 2010 TenneT TSO GmbH was established as the German subsidiary company of the Dutch transmission system operator TenneT. As the first cross-border TSO in Europe, the company connects power lines between Germany and the Netherlands and is strongly involved in international cooperation and transfer of expertise, particularly in the offshore sector.
10,700 kilometres of ultra-high voltage grid are operated, maintained and developed by TenneT TSO and its 1,700 employees. The control area reaches all the way from Schleswig-Holstein in the north, through Lower Saxony and Hesse down to Bavaria in the south of the country. German executive management operates from Bayreuth, other key centres of operation are located in Lehrte near Hanover and in Bamberg. The TenneT grid is monitored from the control centres established in Lehrte and Dachau, near Munich, where load flow and power system security calculations are made as well as forecasts for electricity demand; these form the foundation of the secure transport of energy throughout Germany and are key to maintaining a stable grid frequency.
TenneT Offshore GmbH, an associate company, deals with all matters concerning connection lines at sea, whilst TenneT TSO handles transmission on land.
Every day, the 600 employees of TransnetBW GmbH provide for the 3,200 km of ultra-high voltage grid in their 34,600 km² region. TransnetBW operates the transmission grid in Baden-Württemberg, which is connected to the national and European integrated grid at a number of cross-border transfer points. At the borders of its control area, it is directly connected not only to grid within Germany, but also to those in France, Austria and Switzerland.
The company’s headquarters are located in Stuttgart, however, the true core of the company lies in Wendlingen, just outside Stuttgart. TransnetBW’s system control centre is one of the most state-of-the-art in Europe; from here the company carries out nationwide load offsetting for energy generated from combined heat and power stations.
Information at a glance
High current cabling
In contrast to high-temperature superconductors, so-called high-current cables have a significantly larger cross-sections compared to standard conductors (see ‘High-temperature superconductor’) and are preferred for technical and economic reasons when constructing new lines along existing or new routes. As a general rule, high-current cabling has a continuous current-carrying capacity of 3,600 or 4,000 A per circuit with a permissible conductor cable end temperature of 80°C. Due to its larger cross-section, high-current cabling results in lower levels of network losses when transporting an identical amount of current and in lower noise levels compared to standard conductors and the above-mentioned HTS lines. Since high-current cables have investment-cost advantages and operators have many years of experience working with this technology, it is generally preferred to HTS-cables.