Portrait

Activities and aims

It was just a few years ago that the average distance between electricity generation and consumption was 80 kilometres. Now it is extremely short due, in part, to decentralised generation with photovoltaics on roofs. Or extremely long, as is the case for transporting wind power from north to south. We are committed to providing a transmission grid that is fast, secure and flexible. What’s more, we are well-positioned to take on the challenges of the energy transition.

Activities and aims

We make connections

We move energy from the point of generation to wherever it is consumed. Throughout Baden-Württemberg, within Germany, in particular from north to south, and across national borders to other European countries. Alongside electricity from conventional power stations, we are integrating increasing volumes of renewable energies in the power supply system.

Numerous interconnection points at the limits of our control area connect the TransnetBW transmission grid to the grids of the two neighbouring operators in Germany and those of our partners in France, Austria and Switzerland. For example, to ensure trouble-free energy transmission to our European neighbours and consequently to support the European internal electricity market, we operate a differentiated bottleneck management policy.

We provide all our partners and customers with our grid services transparently and equitably.

Activities and aims

We ensure reliability

A round-the-clock extra-high voltage supply that is stable at all times at a frequency of 50 hertz – that is our measure of reliable, uninterrupted grid operation. And delivering it is the task of our experts in the System Control Centre (SCC) in Wendlingen, 20 kilometres south-east of Stuttgart. The SCC is one of the most modern control centres of its type in Europe and is the heart of our transmission grid. This is where the grid is managed by constantly ensuring the balance between electricity generation and consumption in our control area. A real challenge. Because the feed-in of wind and solar energy cannot be precisely planned.

The tasks performed by our personnel to ensure grid stability include

  • load-frequency control, that is to say the use of control reserves to ensure that the grid operates stably at 50 hertz throughout Europe.
  • scheduling, or the coordination of the import, export and power station schedules of electricity traders and power station operators in our control area.
  • harmonisation of forecast and actual wind and solar feed-in power.
  • compensation for grid losses due to technical reasons during electricity transmission.


To ensure optimum grid reliability, all circuit planning at the SCC in Wendlingen is closely coordinated with the neighbouring domestic and international grid operators. Grid reliability is calculated every five minutes and daily load flow forecasts for the following day help our system control engineers assess the situation on the grid.

And if, despite all this, the balance of the grid does occasionally become disrupted then rapid action is called for. In such cases, TransnetBW’s experts stabilise the grid in direct consultation with the power stations, grid operators and other market stakeholders. One central measure is redispatching – the rapid adaptation of the originally planned power station utilisation to the current grid situation. However strongly the wind blows or the sun shines.

To guarantee the greatest possible reliability of our extra-high voltage grid, we also pay great attention to the maintenance of our technical equipment. TransnetBW’s approach to ensuring reliability includes compliance with legal requirements, our corporate principles and our customers’ guidelines, transport and functional security, the preservation of the value of the assets we maintain, as well as environmental protection requirements. This process is also embedded in our maintenance strategy. This is regularly reviewed and is implemented in practice by our grid service team – which also works out of our Wendlingen site.

Activities and aims

We take responsibility

The transformations taking place in the field of energy generation and provision (the “energy transition”) are confronting transmission grid operators with new challenges. The growth in renewable energies is continuing and politicians want these sources to account for some 80 percent of supplied energy by 2050. At the same time, the need for a reliable electricity supply is also growing. What will be needed in the future is a range of instruments for the integration of renewable energies, in order to ensure a stable European electricity market and harmonious grid technology. Our role as a transmission grid operator is changing – from electricity supplier to electricity manager.

Our core responsibilities lie in the field of developing and expanding the grid. To achieve this, we work closely with our partners:

  • We are planning and implementing the SuedLink wind power line in the company of transmission grid operator TenneT. At a length of approximately 700 kilometres, SuedLink is the largest infrastructure project being undertaken as part of the energy transition: The high-power north-south connection has been designed to transport wind energy from northern coastal regions down to the south of Germany. Consultations are currently underway with the six German states that SuedLink will pass through. And we are conducting a far-reaching dialogue with local inhabitants to increase acceptance of this forward-looking grid expansion in the form of an underground cable.
  • We are working on the ULTRANET grid expansion project in cooperation with Amprion. ULTRANET is also dedicated to the transmission of wind energy (in this case from offshore wind parks in the North Sea off the coast of Emden): This “power bridge” spans the 340 kilometres between Osterath in North Rhine-Westphalia and Philippsburg in Baden-Württemberg. With ULTRANET, we have our sights set firmly on the future: This DC project is being implemented on an existing AC line. What this actually means is that DC and AC currents are to be transported on the same overhead power line. This innovative solution has the advantage that no new lines or work affecting the landscape are necessary.

What is more, every day we are addressing and re-addressing our growing responsibilities in terms of the energy transition. For example, through:

  • System services to enhance the quality of the power supply,
  • Bottleneck management,
  • Fair trading of the electricity fed in from renewable energy sources in our control area on the electricity exchange in Leipzig (as required by legislation),
  • Numerous measures to ensure reliability, transparency and the protection of the environment.


We never stop thinking about the future – with innovation projects and plans for further grid development. Here, too, we are aware of our responsibility for transforming the way energy is generated, distributed and consumed, as well as of our role as an important electricity hub in the heart of Europe.