Our key tasks

We are primarily tasked with providing power transmission services, system services and facilitating the energy market. Our core tasks follow from our appointment as grid operator under the Dutch 'Elektriciteitswet' (E-wet) and the German 'Energiewirtschaftsgesetz' (EnWG).

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TenneT presents Hub and Spoke concept for large scale wind energy on the North Sea.

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Our grid

TenneT manages the high-voltage grid in the Netherlands and large parts of Germany. TenneT transmits electricity at 110,000 volts (110 kV) and higher. With around 23,500 kilometres of high-voltage lines, we cross borders and connect countries.

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Offshore 2030

By 2030, the originally planned capacity of 15 gigawatts of offshore wind energy will increase to 20 GW.

To Offshore 2030
Electricity market

The energy sector is developing rapidly. The process of European market integration began some years ago. Its purpose is to create a single European market that enables market parties to trade gas and electricity across national borders easily and efficiently.

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Transparency data

We provide transparency data on our operations on our Dutch and German transparency page and on ENTSO-E. 

To transparency pages

Our vision is to be one of the most transparent Transmission System Operators (TSO) in Europe and thereby creating value for society. In this Energy Insights section we present selected energy related topics and show data, information and valuable insights. 



Facts & figures related to TenneT facilitating the market can be found here.

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TenneT is a leading European electricity transmission system operator (TSO), with activities in the Netherlands and in Germany. We strive to ensure a reliable and uninterrupted supply of electricity in our high-voltage grid for some 42 million people.

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We are TenneT

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"Sockets" at sea and on land

Converter stations at sea and on land are the heart of an offshore grid connection: They ensure that the electricity generated at sea can be fed into the power grid. Converters have the task of adapting the voltage and converting the current from three-phase to direct current or from direct current back to three-phase current. Two converter stations are required for this process: one at sea and one on land. 

The electricity generated at sea is first collected in the wind farm's own transformer station and fed to the converter platform at sea via a three-phase power cable with a voltage of 155 kilovolts (kV). Inside the converter, power transformers increase the voltage to the converter operating voltage of 320 kV. The three-phase current is then converted into direct current and smoothed. This makes the DC system easier to control. This is important for the stability of the electricity supply, because the wind energy generated at sea is a volatile energy source. This means that it is subject to fluctuations due to the weather as well as seasonal and daily fluctuations and is therefore not produced evenly but fluctuating, e.g. depending on wind conditions. As a result, the volatily-generated wind power often contains so-called vibrations. These are disturbing in the European grid, where a "smooth" frequency of 50 Hertz is required.

From the DC area of the platform, two DC cables (one positive and one negative pole) lead down into the seabed and from there are led towards the mainland to the so-called landing point. This point marks the transition from sea to land. From here, the electricity is transported to the shore side converter station via an underground cable, converted back into three-phase current and transformed to the correct voltage. In the transformer station, the wind power is then fed into TenneT's transmission grid.

Converter platforms are installed at water depths of 27 to 40 metres and project between 40 and 60 metres out of the water. This means that the part of the platform above water is about twice as high as the Brandenburg Gate. The stations are usually more than 100 kilometres from the mainland and therefore not visible from land.