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 24,500 kilometres of high-voltage lines, we cross borders and connect countries.

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Offshore Outlook 2050

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

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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. 

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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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Infrastructure management

Regular maintenance of the infrastructure helps to minimise the risk of power failures, damage to the environment and safety incidents.

Security of supply

As the manager of the Dutch high-voltage grid and a large part of the German high-voltage grid, one of our main tasks is to make sure the infrastructure – the substations, power lines and cables – is always in good working order. 

Regular maintenance of the infrastructure helps to minimise the risk of power failures, damage to the environment and safety incidents. We do this in the best possible way and at an acceptable cost. After all, our customers expect a reliable energy supply at a reasonable price. We therefore pay considerable attention to new maintenance methods and techniques so that we are continually improving.


Our high-voltage transmission grid spans around 23,000 kilometers and high voltage substations. We take preventive measures to ensure it always functions well: we carry out regular inspections and maintenance work. If there is a fault, we repair it. Such faults, however, rarely lead to power outages in our network.


The substations are equipped with transformers. These increase or decrease the voltage so we can connect 380 kV power lines to 220 kV lines and to the regional grid operators (50 kV and below). Transformers have a long lifespan and can work for decades. We therefore inspect them regularly, along with the other equipment located in and around the transformer. 

Power lines and masts

Power lines and pylons are relatively low maintenance. They last for decades, with pylons requiring little more than an occasional new coat of paint. We inspect the connections every 8 to 10 years and randomly carry out top-to-toe mast inspections. Parts of the mast that do sometimes need replacing are the insulator strings, which separate the live power lines from the pylons, and the spacers, which keep the lines far enough away from each other.  

Every year, we carry out aerial inspections by helicopter of the conductors, the suspension and the buildings near the power lines. We also maintain the trees and plants around the substations, pylons and high-voltage lines so they don’t obstruct the energy supply. 


Maintenance strategy

The upkeep of the high voltage network is one of TenneT’s most important tasks. It reduces the risk of disruptions and ensures the security of the electricity supply.

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TenneT is aware of its responsibility for the living environment of people, animals and plants. We want to reduce the impact of our activities and our high-voltage grid on the surrounding area as much as possible.

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Grid expansion

To be able to transmit all the electricity generated by these  new power plants, TenneT is carrying out a large-scale expansion programme.

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